long-term monitoring of pipe under deep cover

Long-Term Monitoring of Pipe Under Deep Cover

Shad M. Sargand Teruhisa Masada

for the

Ohio Department of Transportation Office of Research and Development

and the

U.S. Department of Transportation Federal Highway Administration

State Job Number 14797(0)

Final Report

September 2007

Ohio Research Institute for Transportation and the Environment

1. Report No. FHWA-OH-2007/15

2. Government Accession No.

3. Recipient’s Catalog No.

4. Title and Subtitle Long-Term Monitoring of Pipe Under Deep Cover

5. Report Date September 2007 6. Performing Organization Code

7. Author(s) Shad M. Sargand; and Teruhisa Masada

8. Performing Organization Report No.

10. Work Unit No. (TRAIS)

9. Performing Organization Name and Address Ohio University Civil Engineering Department - ORITE Stocker Engineering Center Athens OH 45701-2979

11. Contract or Grant No. 14797 (0)

13. Type of Report and Period Covered Final Report

12. Sponsoring Agency Name and Address Ohio Department of Transportation Office of Research and Development 1980 West Broad St. Columbus OH 43223

14. Sponsoring Agency Code

15. Supplementary Notes Prepared in cooperation with the U.S. Department of Transportation, Federal Highway Administration 16. Abstract

In the study described in this report, the ORITE research team monitored from 2000 to 2005 the field structural performance of the eighteen thermoplastic pipe structures at the deep burial project site located in Albany, Ohio. In the fall of 2004, the team introduced controlled cuts or notches to the select pipe structures and recorded the pipe wall responses to the defects using strain gages. The team also removed small coupon specimens from the end sections of the select 7-year old thermoplastic pipes and examined them by the standard tensile modulus/strength test method in the laboratory.

The long-term field data indicated that the pipe deflections had been fairly stable since the first year, while the soil pressures acting around the pipes had been fluctuating seasonally in each year. According to theoretical analysis, seasonal changes in the air temperature were responsible for the soil pressure fluctuations, not the seasonal changes in the soil moisture conditions.

During the in-situ notching experiments, strains induced in the pipe wall by the notching process always disappeared quickly within 10 seconds. There were no signs of slow crack growth observed. This was even true for the longitudinal cuts made at the crown, where tensile stresses usually exist. The laboratory tensile strength test results showed that the tensile properties of the thermoplastic did not degrade at all over the 7 year period.

Overall, the long-term phase of the ORITE thermoplastic pipe deep burial project showed that stress relaxation tends to govern the field behaviors of the buried thermoplastic pipe than creep. The long-term performance data collected during this unique field study reaffirmed the importance of installing these thermoplastic pipes properly according to the current ODOT specifications. 17. Key Words Field Performance, Buried Pipe, Thermoplastic, Long-Term, Deflections, Soil Pressure, Notching Test, Tensile Modulus, Tensile Strength

18. Distribution Statement No restrictions. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161.

19. Security Classif. (of this report) Unclassified

20. Security Classif. (of this page) Unclassified

21. No. of Pages 236

22. Price

FORM DOT F 100.7 (8-72) Reproduction of complete pages authorized

Long-Term Monitoring of Pipe Under Deep Cover

Final Report

by

Shad M. Sargand, Ph.D. (Russ Professor); and Teruhisa Masada, Ph.D. (Professor)

Ohio Research Institute for Transportation and the Environment (ORITE),

Civil Engineering Department Russ College of Engineering and Technology,

Ohio University

E-Mail: [email protected] Tel: (740) 593-1465

Credit Reference: Prepared in cooperation with the Ohio Department of Transportation and the U.S. Department of Transportation, Federal Highway Administration. Disclaimer Statement: The contents of this report reflect the views of the author who is responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views of the Ohio Department of Transportation or the Federal Highway Administration. This report does not constitute a standard, specification or regulation.

September 2007

v

TABLE OF CONTENTS

TABLE OF CONTENTS ……………………………………………………. Page v

LIST OF TABLES ……………………………………………………………. Page viii

LIST OF FIGURES ……………………………………………………………. Page x

CHAPTER 1: INTRODUCTION ………………………………….…. Page 1

1.1 Background ………………………………………….…………. Page 1

1.2 Objectives ……………………………………………………. Page 2

1.3 Benefits …………………………………………………….. Page 2

CHAPTER 2: LITERATURE REVIEW …………………………….. Page 5

2.1 General …………………………………………………….. Page 5

2.2 Theoretical Aspects …………………………………………….. Page 5

2.3 Laboratory Experiments …………………………………….. Page 12

2.4 Field Performance …………………………………………….. Page 13

2.5 Slow Crack Growth …………………………………………….. Page 15

CHAPTER 3: METHODOLOGY ………………………………….…. Page 19

3.1 Introduction …………………………………………………….. Page 19

3.2 Initial Findings from Deep Burial Study …………………….. Page 22

3.2.1 General …………………………………………….. Page 22

3.2.2 Pipe Deformations …………………………………….. Page 23

3.2.3 Soil Pressure Against Buried Pipe …………….………. Page 27

3.2.4 Vertical Extent of Soil-Pipe Interaction Zone …….. Page 29

3.2.5 Soil Arching …………………………………………….. Page 30

3.2.6 Effect of Bedding Layer Thickness …………………….. Page 30

3.3 Field Instrumentations and Monitoring …………………….. Page 31

3.4 In-Situ Pipe Notching Experiment …………………………….. Page 33

3.5 Laboratory Coupon Testing …………………………………….. Page 34

vi

TABLE OF CONTENTS (cont’d)

CHAPTER 3:

3.6 Pipe Wall Stability …………………………………………….. Page 35

CHAPTER 4: RESEARCH RESULTS …………………………….. Page 37

4.1 Introduction …………………………………………………….. Page 37

4.2 Long-Term Pipe Deflections & Circumferential Shortening …….. Page 37

4.3 Regression Analysis …………………………………………….. Page 53

4.4 Long-Term Soil Pressure Readings …………………………….. Page 58

4.5 Further Comments …………………………………….. Page 68

4.6 In-Situ Pipe Notching Experiments …………………………….. Page 69

4.7 Laboratory Coupon Testing …………………………………….. Page 78

4.8 Pipe Wall Bucking Tests …………………………………….. 2

4.9 Additional Information …………………………………….. Page 83

CHAPTER 5: SUMMARY AND CONCLUSIONS …………….. Page 87

5.1 Summary …………………………………………………….. Page 87

5.2 Conclusions …………………………………………………….. Page 89

5.2.1 Conclusions for Long-Term Field Performance of

Deeply Buried Thermoplastic Pipe …………………….. Page 89

5.2.2 Conclusions from Regression Analysis of Pipe

Deflection Data …………………………………….. Page 90

5.2.3 Conclusions from Detailed Field Data Analysis …….. Page 92

5.2.4 Conclusions from Theoretical Analysis …………….. Page 93

5.2.5 Conclusions from In-Situ Pipe Notching Experiments …… Page 94

5.2.6 Conclusions from Laboratory Coupon Testing …………... Page 95

5.2.7 Conclusions from Joint Integrity Observations ………….. Page 95

CHAPTER 6: IMPLEMENTATIONS …………………………….. Page 97

vii

TABLE OF CONTENTS (cont’d)

REFERENCES …………………………………………………………….. 9

APPENDIX A: SOIL PRESSURE & PIPE DEFLECTION DATA …….. Page 103

APPENDIX B: REGRESSION ANALYSIS OF LONG-TERM

PIPE DEFLECTIONS …………………………………………….. Page 143

APPENDIX C: EFFECT OF TEMPERATURE ON SOIL

PRESSURE READINGS …………………………………………….. Page 163

APPENDIX D: EFFECT OF TEMPERATURE ON PIPE

DEFLECTIONS …………………………………………………….. Page 187

APPENDIX E: THEORETICAL CONSIDERATIONS …………………….. Page 209

viii

LIST OF TABLES

Table 2.1: Time-Lag Factor Values for USBR Equation …………..… Page 11

Table 2.2: Plastic Pipe Deflection Data from Maine Study ……………. Page 14

Table 3.1: Test Pipe Installation Conditions …………………………….. Page 20

Table 3.2: Basic Engineering Properties of Six Pipe Products …………….. Page 21

Table 3.3: Basic Properties of Soil Materials Utilized in Pipe Installations …. Page 22

Table 3.4: Summary of Vertical Deflection Data …………………….. Page 25

Table 3.5: Summary of Horizontal Deflection Data …………………….. Page 25

Table 3.6: Summary of Vertical to Horizontal Deflection Ratio Value …….. Page 26

Table 3.7: Summary of Circumferential Shortening Data …………….. Page 26

Table 3.8: Summary of Vertical Soil Pressure Measured at Pipe Crown …… Page 28

Table 3.9: Summary of Lateral Soil Pressure Measured at Springline ……… Page 28

Table 3.10: Summary of Crown/Springline Radial Soil Pressure Ratio

Value …………………………………………………………..… Page 29

Table 3.11: Percentage of Geostatic Pressure Measured at Pipe Crown …….. Page 30

Table 4.1: Summary of Vertical Deflection Data (Current Study) ……. Page 47

Table 4.2: Summary of Horizontal Deflection Data (Current Study) ……. Page 47

Table 4.3: Summary of Vertical to Horizontal Deflection Ratio Data

(Current Study) ……………………………………………. Page 48

Table 4.4: Summary of Circumferential Shortening Data (Current Study) …. Page 48

Table 4.5: Summary of Vertical Deflection Data (Both Studies) ……. Page 49

Table 4.6: Summary of Horizontal Deflection Data (Both Studies) ……. Page 49

Table 4.7: Summary of Vertical to Horizontal Deflection Ratio Data

(Both Studies) ……………………………………………. Page 50

Table 4.8: Summary of Circumferential Shortening Data (Both Studies) …. Page 50

Table 4.9: Summary of Long-Term Pipe Deflection Numerical Analysis ….. Page 53

Table 4.10: Summary of Tensile Strength Test Results ……………………. Page 82

Table 4.11: Yield Strength Requirements Based on Cell Class ……………. Page 82

Table C.1: Linear Regression Analysis for Vertical Pressure at Crown ……. Page 183

Table C.2: Linear Regression Analysis for Lateral Pressure at Springline …. Page 184

ix

LIST OF TABLES (cont’d)

Table C.3: Linear Regression Analysis for Vertical Pressure at Invert ……. Page 185

Table D.1: Linear Regression Analysis for Vertical Deflection ……………. Page 206

Table D.2: Linear Regression Analysis for Horizontal Deflection .…………. Page 207

Table E.1: Results of Analysis Based on Elastic Solutions …………………. Page 213

x

LIST OF FIGURES

Figure 2.1: Four-Element (or Burgers) Model …………………………….. Page 6

Figure 2.2: Behavior of Burgers Model (Under Constant Stress) …………….. Page 8

Figure 3.1: Aerial View of Deep Burial Project Site …………………….. Page 19

Figure 3.2: Final Fill Heights Over Test Pipes …………………………….. Page 20

Figure 3.3: Profile-Wall Designs of Six Pipe Products …………………….. Page 21

Figure 3.4: Linear Potentiometers …………………………………………….. Page 31

Figure 3.5: Earth Pressure Cells …………………………………………….. Page 32

Figure 3.6: Laser Profile-Meter …………………………………………….. Page 33

Figure 4.1: Long-Term Deflections of Test Pipe 1 …………………….. Page 38


















Figure 4.19: 100-Year Vertical Deflections (Test Pipes 1-6) …………….. Page 54



xi

LIST OF FIGURES (cont’d)

Figure 4.22: Soil Pressures Measured Around Test Pipe 1 …………….. Page 58


Figure 4.24: Additional Soil Pressure Measurements Taken for Test Pipe 2 ….. Page 59










Figure 4.34: Additional Soil Pressures Measurements Taken for Test Pipe 11 .. Page 64








Figure 4.42: Locations of Cuts and Strain Gages ……………………………. Page 68

Figure 4.43: Notch #2 in Crown Region by Strain Gages #3 and #4 ……. Page 71

Figure 4.44: Notch #3 in Crown Region by Strain Gages #5 and #6 ……. Page 71

Figure 4.45: Strain Gage Responses to Introduction of Notch #1

(Test Pipe 15) ……………………………………………………. Page 72


(Test Pipe 15) ……………………………………………………. Page 72


(Test Pipe 15) ……………………………………………………. Page 73

xii



(Test Pipe 15) ……………………………………………………. Page 73


(Test Pipe 12) ……………………………………………………. Page 74


(Test Pipe 12) ……………………………………………………. Page 74


(Test Pipe 12) ……………………………………………………. Page 75


(Test Pipe 12) ……………………………………………………. Page 75


(Test Pipe 6) ……………………………………………………. Page 76


(Test Pipe 6) ……………………………………………………. Page 76


(Test Pipe 6) ……………………………………………………. Page 77


(Test Pipe 6) ……………………………………………………. Page 77

Figure 4.57: Trimming of Circumferential Direction Coupons ……………. Page 79

Figure 4.58: Typical Test Set-up for Tensile Strength Test ……………. Page 80

Figure 4.59: Coupon Specimens Before and After Test ……………………. Page 80

Figure 4.60: Elongation of Coupon During Tensile Strength Test ……. Page 81

Figure 4.61: Typical Stress-Strain Plot from Tensile Strength Test ……. Page 81

Figure 4.62: General View of Pipe Joint Section Inside Test Pipe 6 ……. Page 83




xiii


Figure B.1: Regression Analysis of Vertical Deflection Changes

Over Time (Pipe 1) ……………………………………………. Page 144

Figure B.2: Regression Analysis of Horizontal Deflection Changes























Over Time (Pipe 7) ……………………………………………. 0



xiv






























xv


















Figure C.1: Correlation Between Temperature and Soil Pressure at Crown

(Test Pipe 1) …………………………………………………….. Page 164

Figure C.2: Correlation Between Temperature and Soil Pressure at Springline

(Test Pipe 1) …………………………………………………….. Page 164


(Test Pipe 2) …………………………………………………….. Page 165


(Test Pipe 2) …………………………………………………….. Page 165

Figure C.5: Correlation Between Temperature and Soil Pressure at Invert

(Test Pipe 2) …………………………………………………….. Page 166

xvi



(Test Pipe 3) …………………………………………………….. Page 166


(Test Pipe 3) …………………………………………………….. Page 167


(Test Pipe 4) …………………………………………………….. Page 167


(Test Pipe 4) …………………………………………………….. Page 168


(Test Pipe 5) …………………………………………………….. Page 168


(Test Pipe 5) …………………………………………………….. Page 169


(Test Pipe 6) …………………………………………………….. Page 169


(Test Pipe 6) …………………………………………………….. Page 170


(Test Pipe 7) …………………………………………………….. Page 170


(Test Pipe 7) …………………………………………………….. Page 171


(Test Pipe 8) …………………………………………………….. Page 171


(Test Pipe 8) …………………………………………………….. Page 172

Figure C.18: Correlation Between Temperature and Soil Pressure at Invert

(Test Pipe 8) …………………………………………………….. Page 172


(Test Pipe 9) …………………………………………………….. Page 173

xvii



(Test Pipe 9) …………………………………………………….. Page 173


(Test Pipe 10) …………………………………………………….. Page 174


(Test Pipe 10) …………………………………………………….. Page 174


(Test Pipe 11) …………………………………………………….. Page 175


(Test Pipe 11) …………………………………………………….. Page 175


(Test Pipe 12) …………………………………………………….. Page 176


(Test Pipe 12) …………………………………………………….. Page 176


(Test Pipe 13) …………………………………………………….. Page 177


(Test Pipe 13) …………………………………………………….. Page 177


(Test Pipe 14) …………………………………………………….. Page 178


(Test Pipe 14) …………………………………………………….. Page 178


(Test Pipe 15) …………………………………………………….. Page 179


(Test Pipe 15) …………………………………………………….. Page 179


(Test Pipe 16) …………………………………………………….. Page 180

xviii



(Test Pipe 16) …………………………………………………….. Page 180


(Test Pipe 17) …………………………………………………….. Page 181


(Test Pipe 17) …………………………………………………….. Page 181


(Test Pipe 18) …………………………………………………….. Page 182


(Test Pipe 18) …………………………………………………….. Page 182

Figure D.1: Correlation Between Temperature at Crown and Deflections

(Test Pipe 1) ………………………………………………….… Page 188

Figure D.2: Correlation Between Temperature at Springline and Deflections

(Test Pipe 1) ………………………………………………….… Page 188


(Test Pipe 2) ………………………………………………….… Page 189


(Test Pipe 2) ………………………………………………….… Page 189


(Test Pipe 3) ………………………………………………….… Page 190


(Test Pipe 3) ………………………………………………….… Page 190


(Test Pipe 4) ………………………………………………….… Page 191


(Test Pipe 4) ………………………………………………….… Page 191


(Test Pipe 5) ………………………………………………….… Page 192

xix



(Test Pipe 5) ………………………………………………….… Page 192


(Test Pipe 6) ………………………………………………….… Page 193


(Test Pipe 6) ………………………………………………….… Page 193


(Test Pipe 7) ………………………………………………….… Page 194


(Test Pipe 7) ………………………………………………….… Page 194


(Test Pipe 8) ………………………………………………….… Page 195


(Test Pipe 8) ………………………………………………….… Page 195


(Test Pipe 9) ………………………………………………….… Page 196


(Test Pipe 9) ………………………………………………….… Page 196


(Test Pipe 10) ………………………………………………….… Page 197


(Test Pipe 10) ………………………………………………….… Page 197


(Test Pipe 11) ………………………………………………….… Page 198


(Test Pipe 11) ………………………………………………….… Page 198


(Test Pipe 12) ………………………………………………….… Page 199

xx



(Test Pipe 12) ………………………………………………….… Page 199


(Test Pipe 13) ………………………………………………….… Page 200


(Test Pipe 13) ………………………………………………….… Page 200


(Test Pipe 14) ………………………………………………….… Page 201


(Test Pipe 14) ………………………………………………….… Page 201


(Test Pipe 15) ………………………………………………….… Page 202


(Test Pipe 15) ………………………………………………….… Page 202


(Test Pipe 16) ………………………………………………….… Page 203


(Test Pipe 16) ………………………………………………….… Page 203


(Test Pipe 17) ………………………………………………….… Page 204


(Test Pipe 17) ………………………………………………….… Page 204


(Test Pipe 18) ………………………………………………….… Page 205


(Test Pipe 18) ………………………………………………….… Page 205

1

CHAPTER 1: INTRODUCTION

1.1 BACKGROUND

The market for large-diameter (24 inches/610 mm or larger in diameter) drainage pipe

products is forecasted to increase by 2.5% annually to 215 million ft (valued at $8.2

billion) by 2010. This growth is fueled by the nation’s needs to revitalize aging and

under-capacity pipeline networks and continued highway and street projects.

Thermoplastic pipes constitute a significant portion of large-diameter drainage pipe

products in the market. They have been utilized in a variety of construction projects.

However, there are very few case studies available in literature concerning the long-term

field performance of the large-diameter thermoplastic pipe products. In addition, there

are some reports issued in the past claiming that thermoplastic materials are susceptible

to slow crack growth when stressed continuously over time. In order to further promote

the use of large-diameter thermoplastic pipe products in civil construction projects, it is

imperative that successful field case studies be published in journals and conference

proceedings.

The ORITE performed a comprehensive field study of large-diameter

thermoplastic pipe at a field site located near Athens, Ohio between the summer of 1999

and the summer of 2002. The findings made during the initial study can be found in the

final report issued by Sargand et al. (2002). This initial study provided detailed field

performance data for thermoplastic pipe from the first one year after installation. The

plastic pipes are manufactured from thermoplastic materials, which tend to exhibit

viscoelastic behavior over time. The viscoelastic behavior, characterized by creep under

2

constant stress and stress relaxation under constant strain, may have a significant

influence on the long-term performance of buried thermoplastic pipe.

1.2 OBJECTIVES

Objectives of the current research project are:

• Determine the long-term performance of thermoplastic pipe under deep soil

cover.

• Provide data for development of cost-effective design and installation

procedures.

• Evaluate the effectiveness of the pipe joints.

• Obtain data on the slow crack growth.

1.3 BENEFITS

The benefits resulting from the current research project are listed below:

• Additional field performance data collected during the four-year extension

period will be instrumental for understanding the long-term structural

performance of deeply-buried thermoplastic pipes.

• The data collected from this study will enhance the knowledge for

development of more rational design procedures for thermoplastic pipes.

• Detailed examinations of the large volume of additional field performance data

may contribute to the current ODOT and AASHTO specifications for

thermoplastic pipes.

3

• Laboratory testing of thermoplastic pipe coupon and sectional specimens will

contribute to further the understanding of the properties of thermoplastic

materials and stability issues related to the profile-wall designs.

• Crack propagation tests to be performed in the field will provide additional

data concerning the stability of the thermoplastic pipe profile-walls.

5

CHAPTER 2: LITERATURE REVIEW

2.1 GENERAL

The field of soil-pipe interaction problem has nearly a century of history, with the initial

steps taken by Marston (1913). Since then, numerous analytical and experimental studies

have been conducted by many researchers to develop design formulas and charts useful

to highway agencies and practicing engineers. Despite the long history enjoyed by the

field of soil-pipe interaction, a general lack of long-term field performance data still

exists when it comes to large-diameter thermoplastic pipes buried under deep soil cover

conditions. This is because of the facts that the thermoplastic pipe is a relatively new

material and that the any scientific investigation into its long-term performance is time-

consuming and costly. Data is especially scarce for the magnitudes and changes of the

pipe deflections and soil pressures around the pipe circumference. This void of

information is due to the facts that the large-diameter thermoplastic pipes are still

relatively new products and that long-term monitoring of deeply buried thermoplastic

pipes is costly and time-consuming. This chapter presents underlying theories on the

long-term field performance of deeply installed thermoplastic pipe and the results of

limited laboratory and field tests.

2.2 THEORETICAL ASPECTS

It is well known that thermoplastic materials such as high density polyethylene (HDPE)

and polyvinyl chloride (PVC) possess viscoelastic properties. They tend to creep under a

constant stress loading and relax under a constant strain loading. For a simple

6

demonstration we may let the four-element rheology model illustrated in Figures 2.1 to

represent the mechanistic nature of the thermoplastic material. The four-element solid

(Burgers) model consists of the Maxwell and the Kelvin elements connected in series.

R2 T2

R1

T1

Kelvin

Maxwell

Figure 2.1: Four-Element or Burgers Model

The building blocks for any of these simple rheology models are a linear spring

(having a spring constant or Young’s modulus of R = σ/ε) and a linear dashpot (having

the coefficient of viscosity η = σ/(dε/dt)). According to Findley et al. (1989), the

differential equations governing the stress-strain behaviors of the Burgers model is:

εεσσσ &&&&&& 2121 qqpp +=++ Burgers Model (2.1)

where p1 = (η1/R1) + (η1/R2) + (η2/R2) = T1 + T2 + T1(R1/R2); p2 = η1η2/(R1R2) = T1T2; q1

= η1 = T1R1; and q2 = η1η2/R2 = T1T2R1.

7

Under a constant stress loading (σ = σ0) applied at t = 0, the time-dependent strain

response will be given by:

( ) ( )[ ] ( )[ ]222 /

2

0

11

0/

2

0

1

1

1

0 1111 TttR eRT

tR

eR

tRR

t −− −+⎟⎟⎠

⎞⎜⎜⎝

⎛+=−+⎟⎟

⎠

⎞⎜⎜⎝

⎛+=

σσση

σε η (2.2)

When the constant load is suddenly removed at t = t1 (> 0), the model experiences an

instantaneous recovery of (σ0/R1) and additional time-dependent recovery. Unlike the

standard solid, this model does not take the strain back to zero as the time goes to + ∞

due to the permanent strain of (σ0 t/η1) experienced by the independent dashpot.

Under a constant strain loading (ε = ε0) applied at t = 0, the time-dependent stress

response will be given by:

( ) ( ) ( )[ ]trtr erqqerqqpp

t 21221121

221

0

4−− −−−

−=

εσ (2.3)

where 2

11 2 p

Apr

−= ;

2

12 2 p

Apr

+= ; and 2

21 4 ppA −= .

Figure 2.2 illustrates the creep and relaxation behaviors of the Burgers model.

8

Figure 2.2: Behavior of Burgers Model (Under Constant Stress)

The above presentation considers only the properties of the thermoplastic pipe

and neglects any mechanistic interactions that take place between the buried

thermoplastic pipe and its surrounding soil medium.

Marston (1913) developed a load theory applicable to buried pipe structure.

Although thermoplastic pipes were not invented at that time, his theory may cast some

light into the long-term performance of buried flexible thermoplastic pipe. According to

Marston, the maximum vertical pressure P acting on top of a buried pipe is estimated by:

P = Cd γ(Bd) (2.4.a)

σ

t

ε

t

9

( )

μ

μ

′−

=′−

KeC

dBHK

d 21 /2

(2.4.b)

where P = vertical pressure acting on a buried pipe; Cd = load coefficient; γ = average

unit weight of soil fill placed above pipe; Bd = pipe trench width; K = Rankine’s active

pressure coefficient = tan2(45° – 0.5φ); μ′ = coefficient of friction along vertical trench

walls; and H = soil cover height above pipe crown.

One shortcoming of the Marston’s load theory is that it is more applicable to rigid pipes.

For a rigid pipe buried in relatively dry sand (γ = 100 pcf = 15.7 kN/m3), the K and μ′

values may be close to 0.33 and 0.50, respectively. Then, the value of Cd will be equal to

1.5 for (H/Bd) ratio of 2.1, 2.0 for (H/Bd) ratio of 3.2, and 3.0 for (H/Bd) ratio of 5.2.

Spangler conducted a series of experiments and accumulated years of field

observations regarding the field performance of relatively flexible corrugated metal pipe

structures. He formulated the horizontal deflection formula on the basis of the elastic

ring theory and the fill-load hypotheses he developed. The formula is commonly known

as the “Iowa formula,” since it was developed at Iowa State College.

( ) 4

3

061.0100

%erEI

KrWDX c

+=

Δ (2.5)

where ΔX = horizontal deflection; D = undeformed pipe diameter; Wc = load acting

across buried pipe per unit length; K = bedding constant; r = undeformed pipe radius; EI

= flexural rigidity of pipe wall section; and e = modulus of passive soil pressure.

10

Watkins and Spangler (1958) examined the previous work by Marston and

Spangler and developed a formula for predicting the horizontal deflection experienced by

a buried flexible pipe structure. The formula is commonly known as the “modified Iowa

formula” and has the form of:

( ) ( ) EPSKPD

DX L

′+=

Δ061.0149.0

100% (2.6)

where DL = time-lag factor; P = vertical pressure acting on pipe; PS = flexural pipe

stiffness (= 6.71EI/r3); and E′ = modulus of soil reaction (= e x r).

They introduced into his pipe deflection formula, the deflection lag factor to account for

the increase in pipe deflection over time. They stated that the DL value of 1.5 would

conservatively account for the long-term effects of side fill consolidation, when the

Marston’s load theory was used to estimate the vertical load acting on the buried pipe.

Alternatively, the DL value may be set equal to 1.0 if the prism load theory is used to

figure out the magnitude of the vertical soil pressure.

Howard (1981) presented the new empirical method of predicting the vertical

deflection of a buried flexible pipe at a conference hosted by ASCE. The method, known

as the USBR equation, was a result of years of back-calculation work conducted at the

Water and Power Services Service (formerly Bureau of Reclamation). The equation had

the following form:

11

( ) ff

ff

f ICDS

rEI

hTY +

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

++⎟

⎠⎞

⎜⎝⎛

=Δ

3

07.0% γ (2.7)

where Tf = time-lag factor; γ = backfill soil unit weight (pcf); h = depth of cover (ft);

EI/r3 = pipe stiffness factor (lb/in2); Sf = soil stiffness factor; Df = design factor; Cf =

construction factor; and If = inspection factor.

Howard commented that the time-lag factor was necessary for predicting the long-term

deflection of the pipe caused by two mechanisms (increase of load over time;

consolidation of side fill over time). Table 2.1 below lists the general values of the time-

lag factor proposed for the USBR equation (Howard, 1981).

Table 2.1: Time-Lag Factor Values for USBR Equation Tf Value for Degree of Compaction Backfill Soil

Classification Dumped Slight (< 85%) Moderate (85-95%)

High (> 95%)

Fine-grained soils (CL, ML, CL-ML)

1.5 2.0 2.5 2.5

Sandy or gravelly fine-grained soils

1.5 2.0 2.5 2.5

Coarse-grained soils with fines

1.5 2.0 2.5 2.5

Clean coarse-grained soils

1.5 2.0 2.5 2.5

Crushed rock 2.0 2.0 3.0 3.0

Janson (1990) used the Spangler-Molin deflection formula to illustrate that a

combination of successive changes in the soil stiffness and the pipe’s short-term ring

12

stiffness must be used to estimate the long-term pipe performance especially when plastic

pipe is buried in cohesive soil.

Petroff (1990) used the viscoelastic model TAMPIPE developed by Chua and

Lytton (1989) to gain theoretical insights into long-term behavior of buried plastic pipe.

The model results showed that: 1) time-dependent deformation of a buried plastic pipe is

controlled by the viscoelastic nature of the backfill soil and pipe; 2) for HDPE pipe

backfilled in dense (>95% SPD) granular material, the load on the pipe reaches its peak at

completion of installation and decreases subsequently with time; 3) for the HDPE pipe, a

large portion (up to 80%) of 100-year creep deflection takes place within 30 days after

construction; 4) the flexible pipe continues to deflect forever but at increasingly smaller

rates; and 5) for HDPE pipe the consequences of creep deflection are insignificant, when

compared with the benefit of stress relaxation.

2.3 LABORATORY EXPERIMENTS

There has been small-scale laboratory or field testing of soil-thermoplastic pipe

interaction problems reported in literature. For example, Sargand et al. (1994) performed

a series of centrifuge model experiments to gain insights into the long-term behaviors of a

HDPE pipe buried under a shallow cover and subjected to surface loading. The concept

behind the centrifuge modeling, which has been explained plainly by Schofield (1988)

and Ko (1988), is that a scaled-down (1/n) model can reflect stress-strain behaviors of the

prototype when it is subjected to an intensified gravitational field (n * g). The centrifuge

device utilized in their study had characteristics of maximum pay load of 100 lbs (445 N),

an arm length of 4.46 ft (1.36 m), and a maximum acceleration of 200G. A miniature

13

HDPE pipe, having an inside diameter of 1.28 inches (32.5 mm), was backfilled with a

clean granular soil inside a large wooden box. A rigid steel plate (3.4-inch or 86-mm

wide x 8.0-inch or 203-mm long) was positioned above the buried pipe for applying the

surface loading. A series of constant stress load test were performed to examine the long-

term deflection performance of the HDPE pipe. According to the test results, the pipe

deflections appeared to stabilize within 40 to 45 minutes upon loading. The deflection

lag factor varied between 1.19 and 1.24, with an average value of 1.21.

Other examples are the soil cell tests performed by Moser et al. (1985) and by

Rogers (1988). However, in these studies, including even the centrifuge model study

mentioned above, a series of highly controlled short-term tests were performed using a

small-scale laboratory test set-up with somewhat unrealistic (= perfectly rigid) boundary

conditions. Long-term field performance data can be produced through a carefully

planned and executed full-scale field burial study.

2.4 FIELD PIPE PERFORMANCE

A literature survey identifies only three case studies – Chambers et al. (1980), Adams,

Muindi, and Selig (1988), and Sargand and Masada (2000), other than the authors’

current study, in which long-term field performance of thermoplastic pipe was recorded

under deep burial conditions.

In the NCHRP project by Chambers et al. (1980), some field studies were

conducted in cooperation with several state highway agencies. In a field study

performed in Maine, six types of thermoplastic pipe were buried, under depths of cover

varying from 2 to 2.5 ft (0.61 to 0.76 m), in a section of an unpaved road adjacent to I-95.

14

The pipe deflections were recorded 6 months and 18 months after installation. The

vertical deflection data for PVC and PE pipes produced in the study are summarized in

Table 2.2.

Table 2.2: Plastic Pipe Deflection Data from Maine Study Vertical Deflection: Pipe Type Date PS

(lb/in/in) % SPD for

Backfill Average Maximum Ave. Increase May 1976 1.6% 3.0% PVC

(DR-35) May 1977 76 92

2.5% 4.1% 56.3%

May 1976 0.8% 1.7% PVC (DR-41) May 1977

45 94 1.4% 3.0%

75.0%

May 1976 4.7% 8.0% PE (Corrugated) May 1977

30 91 8.5% 11.5%

80.9%

May 1976 4.4% 5.8% PE (Smooth-wall) May 1977

18 93 6.9% 9.0%

56.8%

[Note] PS = Pipe Stiffness (measured); and SPD = Standard Proctor Test.

The vertical deflection of both the PVC and PE pipes increased over the 1-year time

period. They attributed this to the combined effects of continued traffic loading and frost

penetration. Examining the data in Table 2.2, the vertical deflection increased on the

average anywhere between 56 and 81%.

Hashash and Selig (1990) published long-term performance data for a 24-inch

(0.61-m) diameter, corrugated HDPE pipe placed under a 100-ft (30.5-m) high

embankment fill. The investigation took place on Interstate 279, north of Pittsburgh in

Pennsylvania. The pipe was backfilled in a dense (100% SPD compaction) crushed

limestone material. The pipe was instrumented extensively with strain coils,

circumferential strain gages, thermistors, and soil stress cells. A sled equipped with a

camera and LVDTs was inserted into the pipe to collect the pipe deformation and distress

data. The soil surrounding the pipe received strain coils. They monitored the pipe

15

performance for two years. They reported that the pipe’s responses to the embankment

loading stabilized shortly after construction. At the end of construction, the pipe

deflections were – 4.0% (vertical) and 0.4% (horizontal). The final stabilized pipe

deflections were – 4.3% (vertical) and 0.6% (horizontal). The circumferential shortening

experienced by the pipe was 1.6%. The vertical soil pressure measured at the pipe crown

corresponded to about 23% of the estimated geostatic pressure produced by the

embankment fill. They observed no signs of structural distress in the pipe during the

two-year study.

2.5 SLOW CRACK GROWTH

The slow crack growth process involves the formation of craze-like damage at the notch

tip and fibrous structure over the failed surface. Here, the craze is a distorted localized

region which forms before cracking due to a high stress and consists of aligned molecular

chains. The fibrous appearance develops because of the breakage of tie molecules under

the constant stress level. Accelerated slow crack growth testing often employs the

creation of a controlled flaw or notch made into the test specimen. Factors that affect the

crack growth rate are the notch characteristics (depth, sharpness), stress level (with

respect to the strength of the polymer), polymer properties (density, molecular weight,

molecular weight distribution, co-monomer distribution), and temperature. The crack

growth rate can be accelerated by lubricating chemical agents. When the chemical agents

are involved in the process, it is called the environmental stress cracking (ESC).

The stress crack growth process can be evaluated in the laboratory. Currently,

ASTM has three different test methods (D-1693, D-5397, and F-2136) which were

16

established for determining the environmental stress crack resistance (ESCR) of polymer

resins. In the ASTM D-1693 method, a small strip of sample is notched 0.3 to 0.4 mm

deep along its length, bent backward and placed in a restraining fixture, and submerged in

a surfactant solution at 50 °C until the notch grows through the specimen. This method,

commonly referred as the “bent-strip test,” is generally useful for PE resins that possess

high densities and low ESCR. Resins having lower densities tend to undergo stress

relaxation quickly and do not fail during this test. In the ASTM D-5397 test, a small

dumbbell-shape specimen is notched 20% of its thickness across the face, placed in a

surfactant solution at 50 °C, and subjected to a constant tensile load until failure. In the

test, commonly referred as the “notched constant tensile load (NCTL) test,” the time to

failure is actually measured for each test specimen. The ASTM F-2136 (notched constant

ligament stress or NCLS) test method is an enhanced version of the NCTL test for

evaluating the ESR of strip specimens cut from the finished pipe products.

NCHRP (NCHRP Report 429, 1999) supported a research project which

examined the stress crack resistance (SCR) of corrugated HDPE pipe materials. In the

study, a survey was conducted to compile general field performance data on the

corrugated HDPE pipes. The survey results showed that overall the HDPE pipes

performed well when installed properly. They could exhibit signs of structural distress

through over-deflection, localized wall buckling, and stress cracking, when installed

improperly. Among the stress cracks detected in the field, circumferential cracking was

more common. The circumferential cracking occurred often at the joint between the

inner liner and the corrugated structural wall. Laboratory tests performed in the study

revealed that pipe resin samples that satisfied basic material specifications (such as

17

density, melt flow index, flexural modulus, tensile strength, …) did not always pass the

SCR test criteria. Further, it was shown through testing of plaques cut from the

manufactured pipes that residual stresses that develop in the longitudinal direction in the

manufacturing process can reduce the SCR against circumferential cracking. It was

found that the specimens cut from the finished pipe in the longitudinal direction and

notched on the exterior surface possessed the shortest failure time.

19

CHAPTER 3: METHODOLOGY

3.1 INTRODUCTION

The thermoplastic pipe deep burial project was launched by the ORITE in the summer of

1999. A total of eighteen thermoplastic (6 PVC, 12 HDPE) test pipes were instrumented

with sensors (linear potentiometers, strain gages, earth pressure cells) and buried under

either 20 ft or 40 ft (6.1 or 12.2 m) of soil fill. Figure 3.1 is an aerial photograph of the

project site, showing initial backfilling process progressing for HDPE pipes in two

trenches. Figure 3.2 illustrates the final embankment fill height configurations achieved

for all the test pipes by the end of December, 2000.

Figure 3.1: Aerial View of Deep Burial Project Site

20

1 2 34 5 67 8 910 11 1213 14 1516 17 18

H = 20 ft

Test Pipe No.

H = 20 ft

H = 40 ft

1 2 34 5 67 8 910 11 1213 14 1516 17 18

H = 20 ft

Test Pipe No.

H = 20 ft

H = 40 ft

Figure 3.2: Final Fill Heights over Test Pipes

Table 3.1 summarizes the installation conditions for the test pipes. The profile-wall types

are classified as A (hollow beam PVC by Vylon), B (corrugated PVC by Contech), C

(corrugated HDPE by Lane), D (corrugated HDPE by ADS), E (corrugated HDPE by

ADS), and F (honeycomb HDPE by ADS).

Table 3.1. Test Pipe Installation Conditions

Backfill: Pipe No.

Pipe Material

Nom. ID (inch)

Wall Type Type RC

Final Fill Height (ft)

Bedding Thickness (inch)

1 Sand 96 20 (6.1 m) 2 96 40 (12.2 m) 3

A Crushed

Rock 86 20 (6.1 m) 4 Sand 86 20 (6.1 m) 5 96 40 (12.2 m) 6

PVC

30.0 (762 mm)

B Crushed Rock 96 20 (6.1 m)

7 96 20 (6.1 m) 8

Sand 96 40 (12.2 m)

9

C

C. Rock 86 20 (6.1 m) 10 Sand 86 20 (6.1 m) 11 96 40 (12.2 m) 12

HDPE 30.0 (762 mm)

D Crushed Rock 96 20 (6.1 m)

6 (150 mm)

13 90 20 (6.1 m) 0-12 (0-300 mm) 14

Sand 96 40 (12.2 m) 3.2-15.2(80-380 mm)

15

42.0 (1,067 mm)

E

90 20 (6.1 m) 0-12 (0-300 mm) 16 90 20 (6.1 m) 3.2-9.2 (80-230 mm) 17

Crushed Rock

96 40 (12.2 m) 6-12 (150-300 mm) 18

HDPE 60.0 (1,524 mm)

F

Sand 96 20 (6.1 m) 3.2-9.2 (80-230 mm) [Note] ID = Inside Diameter; and RC = Relative Compaction.

21

Table 3.2: Basic Engineering Properties of Six Pipe Products Utilized Pipe Type

Pipe Material

Nominal Inside

Diameter (in)

Pipe Wall

Type*

Pipe Wall Area

(in2/in)

Pipe Wall Moment of Inertia

(in4/in)

Pipe Stiffness + (lb/in/in)

A PVC 30 Hollow Beam 0.434 0.051 44 B PVC 30 Corrugated 0.475 0.111 95 C HDPE 30 Corrugated 0.377 0.285 71 D HDPE 30 Corrugated 0.392 0.287 80 E HDPE 42 Corrugated 0.430 0.521 60 F HDPE 60 Honey-Comb 0.657 0.853 34

[Note] * See Figure 3.3 for the illustration of each profile-wall design. + Instantaneous values.

Typical Crossection of Lane 30" HDPE Pipe

4.16"

2.51"

0.105" 0.164"

0.105"

Typical Crossection of Lane 30" HDPE Pipe

4.16"

2.51"

0.105" 0.164"

0.105"

Typical Crossection of ADS 30" HDPE Pipe

4.25"

2.4"

0.24"0.11"

0.18"


4.25"

2.4"

0.24"0.11"

0.18"

Typical Crossection of Vylon 30" PVC Pipe

1.01"

0.2"

0.59" 0.138"

Typical Crossection of Vylon 30" PVC Pipe

1.01"

0.2"

0.59" 0.138"


2.92"2.6"2.7"

0.16"

0.14"Typical Crossection of ADS 60" HDPE Pipe

2.92"2.6"2.7"

0.16"


3.16"

5.20"

0.13"

0.18"


3.16"

5.20"

0.13"

0.18"

0.35"

Typical Crossection of Contech 30" PVC Pipe

0.148"

0.149" 0.159"

1.185"1.33"

Typical Crossection of Contech 30" PVC Pipe

0.148"

0.149" 0.159"

1.185"1.33"

[A] [B]

[C] [D]

[E] [F]

Figure 3.3: Profile-Wall Designs of Six Pipe Products The average initial inside diameter was 29.31” (745 mm) for Type A, 28.98” (736 mm)

for Type B, 29.11” (739 mm) for Type C, 29.29” (744 mm) for Type D, 41.18” (1,046

mm) for Type E, and 59.60” (1,514 mm) for Type F. These were measured immediately

before the initial backfilling process. Table 3.3 lists the basic characteristics of the two

backfill materials and the embankment fill material utilized in the project.

22

Table 3.3: Basic Properties of Soil Materials Utilized in Pipe Installations (a) Crushed Limestone

Percent Passing by Mass (%): Sieve No. & Size ODOT Specification Lab (Typical)

50.8 mm (2.000 in.) 100 100 25.4 mm (1.000 in.) 70 to 100 98.0 19.1 mm (0.750 in.) 50 to 90 90.5

No. 4 – 4.76 mm (0.187 in.) 30 to 60 46.8 No. 30 – 0.590 mm (0.023 in.) 9 to 33 14.4

No. 200 – 0.074 mm (0.0030 in.) 0 to 13 5.0 (b) Sand

Percent Passing by Mass (%): Sieve No. & Size ODOT Specification Lab (Typical)

63.5 mm (2.500 in.) 100 100 25.4 mm (1.000 in.) 70 to 100 100

No. 4 – 4.76 mm (0.187 in.) 25 to 100 100 No. 40 – 0.420 mm (0.0165 in.) 5 to 50 43.6

No. 200 – 0.074 mm (0.0030 in.) 0 to 10 2.0 (c) Embankment Fill Material

Tests Test Results Atterberg Limits 27.2% (LL); 16.5% (PL) 10.7% (PI)

Average In-Situ Unit Weight 130 pcf (20.4 kN/m3) 3.2 INITIAL FINDINGS FROM DEEP BURIAL STUDY Findings that the author made during the first one year of the deep burial study have been

presented in several publications (final report by Sargand et al. 2002; papers by Sargand

et al. 2001, 2002, 2003a, 2003b, 2004, 2005; paper by Masada and Sargand 2005). They

are summarized below.

3.2.1 General

Minor peaking behavior, represented by 0.3 to 0.8% vertical deflection and - 0.2 to -

0.6% horizontal deflection, was recorded during the initial backfilling of each test pipe.

All of the pipes were performing well under the loading from high soil cover during the

23

first year. Most of the pipes experienced vertical deflections of less than - 4%, horizontal

deflection of less than 2%, and circumferential shortening of less than - 1%. Pipe wall

strains (measured by the fiber-optic strain gages) remained mostly within + 0.1% on the

surfaces of the PVC pipe walls and within + 0.02% on the surfaces of the HDPE pipe

walls. Vertical soil pressure measured at the crown ranged from 6 to 14 psi (41 to 97

kPa) under the 20-ft (6.1-m) fill and from 11 to 25 psi (76 to 172 kPa) under the 40-ft

(12.2-m) soil fill. Lateral soil pressure measured at the springline ranged from 6 to 17 psi

(41 to 117 kPa) under the 20-ft (6.1-m) fill and from 9 to 25 psi (62 to 172 kPa) under the

40-ft (12.2-m) soil fill. Signs of structural distress/failure (such as excessive flattening,

reversal of curvature, localized wall buckling, tearing of the seams, opening of joints,

etc.) were not detected anywhere on the interior surfaces of the pipes.

3.2.2 Pipe Deformations

Tables 3.4 through 3.7 summarize the pipe deformations data (vertical deflection,

horizontal deflection, vertical/horizontal deflection value, circumferential shortening)

collected in the field. In these tables, the shapes they had at the completion of the initial

backfilling (1-ft or 0.3-m soil cover above the pipe) were treated as the initial shapes.

The deflections reported here are the deflections the pipes experienced subsequent to the

initial backfill stage. This arrangement was necessary so as to remove the effect of the

initial peaking from the deflection data (i.e., let the deflection data reflect the effect of the

embankment fill loading). The following observations were made while examining the

data contained in the table from several different angles:

24

• Compaction dry density initially achieved on the backfill soil had a major

influence on both short-term and long-term deflections.

• Deflection lag factor, computed by dividing the end-of-construction vertical

deflection by the long-term vertical deflection, varied mostly between 1.0 and

1.4.

• Deflection lag factor was slightly larger in the crushed rock backfill than in

the sand backfill.

• |Vertical/horizontal| deflection ratio was slightly larger for the thermoplastic

pipes installed in dense backfill soil.

• |Vertical/horizontal| deflection ratio was larger in the sand backfill than in the

crushed rock backfill.

• The pipes experienced a larger circumferential shortening in the sand backfill

than in the crushed rock backfill.

• Under very similar installation conditions, the HDPE pipes deflected

vertically more than the PVC pipes.

• Under very similar installation conditions, the HDPE pipes deflected

horizontally less than the PVC pipes.

• Under very similar installation conditions, the HDPE pipes shortened

circumferentially more than the PVC pipes.

• Under very similar installation conditions, deflection lag factor was slightly

smaller for the HDPE pipes than for the PVC pipes.

25

Table 3.4: Summary of Vertical Deflection Data Vertical Deflection (%):

Test Pipe No.

Pipe Type

End of Construction

(A)

3 to 4 Months Later (B)

End of Initial Study Period

(C)

(B/A)

(C/A)

1 -0.81 -0.93 -0.86 1.15 1.06 2 -1.75 -1.73 -1.78 0.99 1.02 3

30” Dia. PVC -1.70 -2.04 -2.22 1.20 1.31

4 -1.27 -1.51 -1.49 1.19 1.17 5 -1.25 -1.52 -1.54 1.22 1.23 6

30” Dia. PVC -0.80 -1.07 -1.00 1.34 1.25

7 -0.78 -0.80 -0.83 1.03 1.06 8 -2.53 -3.18 -3.18 1.26 1.26 9

30” Dia.

HDPE -2.10 -2.37 -2.38 1.13 1.13 10 -3.49 -3.91 -3.83 1.12 1.10 11 -2.74 -3.20 -3.33 1.17 1.22 12

30” Dia.

HDPE -1.43 -1.79 -1.76 1.25 1.23 13 -1.36 -1.90 -2.06 1.40 1.51 14 -2.19 -2.26 -2.29 1.03 1.05 15

42” Dia.

HDPE -1.06 -1.45 -1.38 1.37 1.30 16 -1.98 -2.70 -2.97 1.36 1.50 17 -5.09 -5.79 -5.91 1.14 1.16 18

60” Dia.

HDPE -0.84 -0.97 -0.91 1.15 1.08 Table 3.5: Summary of Horizontal Deflection Data

Horizontal Deflection (%): Test Pipe No.

Pipe Type

End of Construction

(A)



(C)

(B/A)

(C/A)

1 0.40 0.49 0.49 1.23 1.23 2 0.80 0.78 0.87 0.98 1.09 3

30” Dia. PVC 1.21 1.56 1.92 1.29 1.59

4 0.75 0.81 0.53 1.08 0.71 5 0.86 1.16 1.24 1.35 1.44 6

30” Dia. PVC 0.98 1.24 1.36 1.27 1.39

7 0.09 0.19 0.17 2.11 1.89 8 0.60 0.70 0.75 1.17 1.25 9

30” Dia.

HDPE 0.58 0.59 0.65 1.02 1.12 10 2.35 2.49 2.59 1.06 1.10 11 1.24 1.33 1.41 1.07 1.14 12

30” Dia.

HDPE 0.63 0.66 0.71 1.05 1.13 13 0.27 0.54 0.67 2.00 2.48 14 0.69 0.64 0.69 0.93 1.00 15

42” Dia.

HDPE 0.28 0.37 0.44 1.32 1.57 16 0.59 0.66 0.62 1.12 1.05 17 1.26 1.20 1.19 0.95 0.94 18

60” Dia.

HDPE 0.09 -0.04 -0.06 -0.44 -0.67 [Note] End of Construction (Dec. 1999); End of Initial Study Period (July 2000).

26

Table 3.6: Summary of Vertical to Horizontal Deflection Ratio Value |Vertical/Horizontal| Deflection Ratio Value: Test

Pipe No.

Pipe Type End of Construction 3 to 4 Months Later End of Initial Study Period

1 2.03 1.90 1.76 2 2.19 2.22 2.05 3

30” Dia. PVC 1.40 1.31 1.16

4 1.69 1.86 2.81 5 1.45 1.31 1.24 6

30” Dia. PVC 0.82 0.86 0.74

7 86.67 4.21 4.88 8 4.22 4.54 4.24 9

30” Dia.

HDPE 3.62 4.02 3.66 10 1.49 1.57 1.48 11 2.21 2.41 2.36 12

30” Dia.

HDPE 2.27 2.71 2.48 13 5.04 3.52 3.07 14 3.17 3.53 3.32 15

42” Dia.

HDPE 3.79 3.92 3.14 16 3.36 4.09 4.79 17 4.04 4.83 4.97 18

60” Dia.

HDPE 9.33 24.25 15.17 Table 3.7: Summary of Circumferential Shortening Data

Circumferential Shortening (%): Test Pipe No.

Pipe Type

End of Construction

(A)



(C)

(B/A)

(C/A)

2 -0.05 -0.09 -0.06 1.80 1.20 5

30” Dia. PVC -0.058 -0.11 -0.04 1.98 0.69

7 -0.21 -0.25 -0.27 1.20 1.29 8 -0.51 -0.79 -0.74 1.56 1.45 9

30” Dia. HDPE

-0.25 -0.20 -0.16 0.79 0.64 10 -0.30 -0.43 -0.30 1.45 1.00 11 -0.40 -0.52 -0.53 1.31 1.33 12

30” Dia. HDPE

-0.20 -0.26 -0.24 1.30 1.20 14 42” Dia.

HDPE -0.72 -0.72 -0.73 1.00 1.01

17 60” Dia. HDPE

-1.97 -1.43 -1.58 0.73 0.80

[Note] End of Construction (Dec. 1999); End of Initial Study Period (July 2000).

27

3.2.3 Soil Pressure Against Buried Pipe Tables 3.8 through 3.10 summarize the soil pressure data (vertical pressure at the crown,

lateral pressure at the springline) collected in the field. The following observations can

be made by reviewing the soil pressure data:

• Compacted dry density initially achieved on the backfill soil had noticeable

influence on the soil pressure that develops against the pipe subsequently.

The higher the relative compaction was, the smaller the magnitude of the soil

pressure acting around the pipe.

• (Crown/springline) radial soil pressure ratio had a tendency to be larger in the

sand backfill than in the crushed rock backfill.

• Under very similar installation conditions, the vertical soil pressure acting

over the PVC pipe was larger than that over the HDPE pipe.

• Under very similar installation conditions, the lateral soil pressure acting

against the sides of the PVC pipe was larger than that against the sides of the

HDPE pipe.

• Under very similar installation conditions, (crown/springline) soil pressure

ratio had a tendency to be larger for the PVC pipe than for the HDPE pipe.

• Under very similar installation conditions, the vertical soil pressure acting

over the pipe had a tendency to increase slightly over time for the PVC pipe

and decline slightly over time for the HDPE pipe.

28

Table 3.8: Summary of Vertical Soil Pressure Measured at Pipe Crown Crown Pressure (psi): Test

Pipe No.

Pipe Type

End of Construction

(A)



(C)

(B/A)

(C/A)

1 10.0 12.8 14.8 1.28 1.48 2 15.8 19.0 21.7 1.20 1.37 3

30” Dia. PVC 11.7 14.1 17.0 1.18 1.42

4 10.7 13.2 15.1 1.23 1.41 5 23.7 25.5 27.0 1.08 1.14 6

30” Dia. PVC 8.5 9.0 13.4 1.06 1.58

7 7.9 7.6 7.3 0.96 0.92 8 14.1 14.0 14.4 0.99 1.02 9

30” Dia.

HDPE 7.5 8.1 8.9 1.08 1.19 10 9.4 8.9 8.3 0.95 0.88 11 11.8 11.6 11.8 0.98 1.00 12

30” Dia.

HDPE 7.8 8.7 9.7 1.12 1.24 13 8.5 8.4 7.6 0.99 0.89 14 14.5 13.5 13.4 0.93 0.92 15

42” Dia.

HDPE 8.6 8.9 9.6 1.03 1.12 16 8.9 9.9 9.8 1.11 1.10 17 13.7 12.7 12.6 0.93 0.92 18

60” Dia.

HDPE 5.8 6.4 8.1 1.10 1.40 Table 3.9: Summary of Lateral Soil Pressure Measured at Springline

Springline Pressure (psi): Test Pipe No.

Pipe Type

End of Construction

(A)



(C)

(B/A)

(C/A)

1 11.9 12.9 13.2 1.08 1.11 2 45.2 48.1 48.9 1.06 1.08 3

30” Dia. PVC 12.1 17.4 20.6 1.44 1.70

4 8.9 10.7 12.3 1.20 1.38 5 22.3 24.9 26.1 1.12 1.17 6

30” Dia. PVC 8.7 10.2 12.8 1.17 1.47

7 6.4 6.5 6.9 1.02 1.08 8 16.3 16.4 16.9 1.01 1.04 9

30” Dia.

HDPE 9.3 8.4 9.3 0.90 1.00 10 9.4 8.7 8.7 0.93 0.93 11 18.3 18.1 18.6 0.99 1.02 12

30” Dia.

HDPE 8.6 10.2 10.9 1.19 1.27 13 8.4 9.7 8.7 1.15 1.04 14 11.9 9.1 9.5 0.76 0.80 15

42” Dia.

HDPE 7.3 8.7 9.7 1.19 1.33 16 14.5 15.5 15.7 1.07 1.08 17 20.3 18.4 17.5 0.91 0.86 18

60” Dia.

HDPE 5.0 5.5 6.8 1.10 1.36 [Note] End of Construction (Dec. 1999); End of Initial Study Period (July 2000). 1 psi = 6.9 kPa

29

Table 3.10: Summary of Crown/Springline Radial Soil Pressure Ratio Value (Crown/Springline) Radial Soil Pressure Ratio: Test

Pipe No.

Pipe Type End of Construction 3 to 4 Months Later End of Initial Study Period

1 0.84 0.99 1.12 2 0.35 0.40 0.44 3

30” Dia. PVC 0.97 0.81 0.83

4 1.20 1.23 1.23 5 1.06 1.02 1.03 6

30” Dia. PVC 0.98 0.88 1.05

7 1.23 1.17 1.06 8 0.87 0.85 0.85 9

30” Dia.

HDPE 0.81 0.96 0.96 10 1.00 1.02 0.95 11 0.64 0.64 0.63 12

30” Dia.

HDPE 0.91 0.85 0.89 13 1.01 0.87 0.87 14 1.22 1.48 1.41 15

42” Dia.

HDPE 1.18 1.02 0.99 16 0.61 0.64 0.62 17 0.67 0.69 0.72 18

60” Dia.

HDPE 1.16 1.16 1.19 [Note] End of Construction (Dec. 1999); End of Initial Study Period (July 2000).

3.2.4 Vertical Extent of Soil-Pipe Interaction Zone

Vertical soil pressure measured at various soil cover heights above Test Pipes 5 and 8

indicated that the pipe-soil interaction zone extends vertically only about one pipe

diameter above the pipe. This finding agreed with a statement made by Hoeg (1968) who

worked on elastic solutions to the buried pipe problems and many laboratory

experiments. Detailed discussions on this finding can be found in a recent paper by

Sargand et al. (2001).

30

3.2.5 Soil Arching

Table 3.11 summarizes the percentage of the estimated geostatic pressure measured at the

crown of each test pipe at the end of construction. The results in the table indicate that:

1) the HDPE pipes, with lower hoop stiffness, promote higher degrees of positive soil

arching than the PVC pipes under similar installation conditions; and 2) the dense (96%)

sand was just as effective as the dense (96%) crushed limestone in relieving the vertical

loads acting over the thermoplastic pipe.

Table 3.11 Percentage of Geostatic Pressure Measured at Pipe Crown Pipe: Backfill Soil: Test

Pipe No.

Nom. ID (in)

Material Type Actual Ave. Compact. (%)

Fill Height

(ft)

% of Geostatic Pressure Measured

(%) * 1 Sand 96.2 20 55.6 2 Crushed Rock 101.0 40 50.3 3

30

PVC

Crushed Rock 86.2 20 69.1 4 Sand 87.8 20 60.4 5 Crushed Rock 96.7 40 66.4 6

30

PVC

Crushed Rock 97.0 20 48.6 7 Sand 95.6 20 42.9 8 Sand 95.6 40 39.2 9

30

HDPE

Crushed Rock 86.9 20 41.9 10 Sand 86.9 20 51.8 11 Crushed Rock 100.0 40 33.0 12

30

HDPE

Crushed Rock 97.6 20 44.2 13 Sand 92.7 20 46.3 14 Sand 94.9 40 40.3 15

42

HDPE

Crushed Rock 89.7 20 53.3 16 Crushed Rock 90.1 20 47.5 17 Crushed Rock 95.6 40 37.4 18

60

HDPE

Sand 94.3 20 34.3 [Note] * These values are based on the data collected at the end of construction. 1 ft = 12 in = 0.3 m.

3.2.6 Effect of Bedding Layer Thickness

As listed in Table 3.1, the bedding layer thickness was 6 inches (150 mm) for Test Pipes

1 through 12 but varied for the remaining test pipes. Extension of the Spangler’s work by

31

Masada (2000) pointed out that a thinner bedding layer might lead to a more concentrated

bottom reaction, increasing vertical deflection, and increasing |vertical/horizontal|

deflection ratio. The cases involving Test Pipes 8 and 14 appeared to support this

hypothesis. Additional case histories are needed to further verify the effect of bedding

layer thickness discussed here.

3.3 FIELD INSTRUMENTATIONS AND MONITORING

A variety of modern sensors/devices were utilized to accomplish the objectives of the

ORITE deep pipe burial project. They were:

• Linear Potentiometers --- for measuring horizontal & vertical diameter

changes as well as circumferential shortening. Figure 3.4 shows how the

linear potentiometers were set up inside each test pipe.

Figure 3.4: Linear Potentiometers

32

• Strain Gages (electric-resistance, fiber-optic) --- for measuring strains on the

surface of pipe wall at the crown and the springline positions.

• Earth Pressure Cells --- for measuring the vertical soil pressure at the crown

and lateral soil pressure at the springlines. Additional pressure cells were

installed for selected test pipes to measure soil pressure at the invert or the

vertical extent of soil-pipe interaction zone. Figure 3.5 presents three

different configurations of the pressure cell installation applied in the project.

Figure 3.5: Earth Pressure Cells

• Laser Profile-meter --- for recording cross-sectional shape of test pipe. Figure

3.6 shows a set of photographs of this equipment developed at ORITE.

33

Figure 3.6: Laser Profile-Meter

3.4 IN-SITU PIPE NOTCHING EXPERIMENT

The current ASTM test (D-1693; D-5397, F-2136) methods described in Section 2.5 are

useful for comparing quality of different resins, optimizing the profile-wall design, and

evaluating the stress crack resistance (SCR) of the thermoplastic pipe material itself.

One major shortcoming these methods share is that they do not provide data that can

reflect the stress crack resistance possessed by the buried thermoplastic pipe. In none of

these tests, the specimens are subjected to the actual field installation/loading conditions.

In none of these tests, the physical interactions between the pipe and its surrounding soil

are addressed.

In the current research project, the stress crack tests were performed in the field,

utilizing some of the test pipes that were installed during the original deep burial project.

In this in-situ test procedure, first strain gages were installed at predetermined locations

within the circumferential section of each test pipe selected for the field testing. Then,

34

controlled physical damages were introduced to the pipe wall surface very close to the

strain gages. The readings from the strain gages were recorded frequently over a short

duration of time just long enough to observe the pipe wall responses to the notching and

thus access the crack growth potential of the pipe material has in the actual field

installation environments.

3.5 LABORATORY COUPON TESTING

One potential concern with the thermoplastic pipe material may be aging. Once installed

in the ground, the pipe is subjected to constant stresses. Also, the pipe end sections are

exposed to ultra-violet (UV) light over a prolonged period of time in each year. It is

possible that the pipe material may undergo some degree of aging (alterations of its

molecular structure) due to the constant stress and environmental exposures.

In the current research project, coupon specimens were cut from the test pipes in

the field and subjected to tensile strength test method in the laboratory to determine their

tensile modulus and strength properties, according to the ASTM D-638 method. The

HDPE material is classified as type IV, so the HDPE pipe coupons with a gage length of

1 inch (25 mm) were loaded at a constant elongation rate of 2 inches/minute (50

mm/minute). Once the test results are obtained, they were compared to the applicable

AASHTO and/or ASTM requirements and the original material specifications to discuss

the degree of aging these test pipes experienced.

35

3.6 PIPE WALL STABILITY

All of the test pipes installed at the ORITE deep burial project site have been performing

well (experiencing relatively small deflections and showing no signs of structural distress

such as cracks and wall buckling) during the past five years, despite the fact that they

have been constantly subjected to a gravitational loading created by a 20-ft (6.1-m) or 40-

ft (12.2-m) high embankment. As part of conducting comprehensive material

characterizations, it may be beneficial to perform a series of stability tests in the

laboratory to evaluate the buckling behavior of the wall profiles the test pipes possess.

The laboratory test results may explain why these pipes have not developed any signs of

wall buckling in the field.

Currently, there are no standard test methods set forth by either ASTM or

AASHTO to evaluate the buckling behavior of the thermoplastic pipe product. In the

ASTM D-2412 (parallel-plate load) test method, the buckling behavior of the pipe wall

section is evaluated visually while the pipe specimen is loaded to a 30% vertical

deflection between two flat parallel plates. This test is performed mainly for measuring

the flexural stiffness of the pipe product, not for determining directly the critical buckling

stress.

37

CHAPTER 4: RESEARCH RESULTS

4.1 INTRODUCTION

During the long-term monitoring phase of the ORITE thermoplastic pipe deep burial

project, the research team continued to record readings from the linear potentiometers

and soil pressure cells that were installed inside/around each of the eighteen test pipes.

The field data collection took place at the project site in Albany, Ohio over a 5-year time

span, from October 2000 to April 2005. The following sections present the long-term

performance data collected in the project by groups, starting from the linear

potentiometer readings.

4.2 LONG-TERM PIPE DEFLECTIONS AND CIRCUMFERENTIAL

SHORTENING

Figures 4.1 through 4.18 plot the linear potentiometer readings against the time elapsed

since the initial pipe installation. These plots contain occasional gaps in the data, because

of the on-going problems in keeping the linear potentiometers from being damaged due

to sediment accumulations and animal crossing. For a number of test pipes (Test Pipes 2,

5, 7, 8, 9, 10, 11, 12, 14, and 17), the linear potentiometer readings included not only the

vertical and horizontal deflections but also the circumferential shortening data.

These plots show that the horizontal deflection remained relatively constant inside

all the test pipes. The circumferential shortening behavior was also relatively unchanged

with time for each test pipe which provided the circumferential shortening data. The

38

vertical deflection continued to increase slightly for Test Pipes 1, 2, 4, 5, 6, 7, and 13.

Their vertical deflections appear to be stabilizing during the last year of the field

monitoring.

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41

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47

Tables 4.1 through 4.4 summarize the time-dependent deformation performance

of the test pipes recorded during the long-term field performance study. The tables were

prepared in the same manner as the way Tables 3.4 through 3.7 were previously prepared.

Table 4.1: Summary of Vertical Deflection Data (Current Study)

Vertical Deflection (%): Test Pipe No.

Pipe Type

End of Initial Monitoring

(A)

1 Year Later (B)

2 Years Later (C)

End of Monitoring

(D)

B/A

C/A

D/A

1 -0.86 -0.86 -1.04 -1.18 1.00 1.21 1.37 2 -1.78 -2.12 -2.37 -2.74 1.19 1.33 1.54 3

30” Dia. PVC -2.22 -2.39 -2.42 -2.45 1.08 1.09 1.10

4 -1.49 -1.72 -1.85 -2.07 1.15 1.24 1.39 5 -1.54 -2.56 -2.61 -2.48 1.66 1.69 1.61 6

30” Dia. PVC -1.00 -1.13 -1.23 -1.35 1.13 1.23 1.35

7 -0.83 -0.88 -0.90 -1.13 1.06 1.08 1.36 8 -3.18 -3.06 -3.16 -3.24 0.96 0.99 1.02 9

30” Dia.

HDPE -2.38 -2.44 -2.55 -2.46 1.03 1.07 1.03 10 -3.83 -4.73 -4.75 -4.87 1.23 1.24 1.27 11 -3.33 -3.68 -3.90 -3.35 1.11 1.17 1.01 12

30” Dia.

HDPE -1.76 -2.15 -2.27 -2.17 1.22 1.29 1.23 13 -2.06 -2.70 NA NA 1.31 NA NA 14 -2.29 -2.61 -2.33 -2.28 1.14 1.02 1.00 15

42” Dia.

HDPE -1.38 -1.85 -1.95 -1.83 1.34 1.41 1.33 16 -2.97 -2.62 -2.69 -2.60 0.88 0.91 0.88 17 -5.91 -6.07 -6.10 -5.98 1.03 1.03 1.01 18

60” Dia.

HDPE -0.91 -0.93 -0.94 -0.89 1.02 1.03 0.98 [Note] End of Initial Monitoring (July 2000); End of Monitoring (April 2004).

Table 4.2: Summary of Horizontal Deflection Data (Current Study) Horizontal Deflection (%): Test

Pipe No.

Pipe Type


(A)

1 Year Later (B)

2 years Later (C)

End of Monitoring

(D)

B/A

C/A

D/A

1 0.49 0.56 0.66 0.59 1.14 1.35 1.20 2 0.87 1.11 1.33 1.49 1.28 1.53 1.71 3

30” Dia. PVC 1.92 2.27 2.28 2.28 1.18 1.19 1.19

4 0.53 0.94 0.95 0.89 1.77 1.79 1.68 5 1.24 2.20 2.43 2.22 1.77 1.96 1.79 6

30” Dia. PVC 1.36 1.77 1.80 1.81 1.30 1.32 1.33

7 0.17 0.15 0.14 0.13 0.88 0.82 0.76 8 0.75 0.64 0.53 0.49 0.85 0.71 0.65 9

30” Dia.

HDPE 0.65 1.13 1.05 1.18 1.74 1.62 1.82 10 2.59 2.98 2.97 2.99 1.15 1.15 1.15 11

30” Dia. 1.41 1.58 1.58 1.54 1.12 1.12 1.09

48

12 HDPE 0.71 0.67 0.58 0.62 0.94 0.82 0.87 13 0.67 0.54 NA NA 0.81 NA NA 14

42” Dia. 0.69 0.66 0.62 0.68 0.96 0.90 0.99

15 HDPE 0.44 0.38 0.30 0.48 0.86 0.68 1.09 16 0.62 0.23 0.20 0.43 0.37 0.32 0.69 17 1.19 1.19 1.18 1.18 1.00 0.99 0.99 18

60” Dia.

HDPE -0.06 -0.08 -0.17 -0.12 1.33 2.83 2.00

Table 4.3: Summary of Vertical to Horizontal Deflection Ratio Data |Vertical/Horizontal| Deflection Ratio: Test

Pipe No.

Pipe Type


1 Year Later

2 years Later End of Current Monitoring

1 1.76 1.54 1.58 2.00 2 2.05 1.91 1.78 1.84 3

30” Dia. PVC 1.16 1.05 1.06 1.07

4 2.81 1.83 1.95 2.33 5 1.24 1.16 1.07 1.12 6

30” Dia. PVC 0.74 0.64 0.68 0.75

7 4.88 5.87 6.43 8.69 8 4.24 4.78 5.96 6.61 9

30” Dia.

HDPE 3.66 2.16 2.43 2.08 10 1.48 1.59 1.60 1.63 11 2.36 2.33 2.47 2.18 12

30” Dia.

HDPE 2.48 3.21 3.91 3.50 13 3.07 5.00 NA NA 14 3.32 3.95 3.76 3.35 15

42” Dia.

HDPE 3.14 4.87 6.50 3.81 16 4.79 11.39 13.45 6.05 17 4.97 5.10 5.17 5.07 18

60” Dia.

HDPE 15.17 11.63 5.53 7.42 [Note] End of Initial Monitoring (July 2000); End of Monitoring (April 2004).

Table 4.4: Summary of Circumferential Shortening Data (Current Study) Circumferential Shortening (%): Test

Pipe No.

Pipe Type


(A)

1 Year Later (B)

2 years Later (C)

End of Monitoring

(D)

B/A

C/A

D/A

2 -0.06 --- -0.07 -0.07 --- 1.17 1.17 5

30” Dia. PVC -0.04 -0.10 -0.13 -0.38 2.50 3.25 9.50

7 -0.27 -0.29 -0.44 -0.29 1.07 1.63 1.07 8 -0.74 -0.81 -1.00 -0.82 1.09 1.35 1.11 9

30” Dia. HDPE

-0.16 -0.27 -0.25 -0.35 1.69 1.56 2.19 10 -0.30 -0.61 -0.51 -0.58 2.03 1.70 1.93 11 -0.53 -0.60 -0.64 -0.69 1.13 1.21 1.30 12

30” Dia. HDPE

-0.24 -0.34 -0.31 -0.33 1.42 1.29 1.38 14 42” HDPE -0.73 -0.83 -0.84 -0.86 1.14 1.15 1.18 17 60” HDPE -1.58 -1.68 -1.70 -1.70 1.06 1.08 1.08

49

Combining the data from the initial and current research projects, one can

summarize the long-term field performance of the test pipes over 5 years beyond the end

of construction. They are presented in Tables 4.5 through 4.8.

Table 4.5: Summary of Vertical Deflection Data (Both Studies)

Vertical Deflection (%): Test Pipe No.

Pipe Type

End of Construction

(A)

1 Year Later (B)

2 years Later (C)

5 Years Later (D)

B/A

C/A

D/A

1 -0.81 -0.86 -1.04 -1.18 1.06 1.28 1.46 2 -1.75 -2.12 -2.37 -2.74 1.21 1.35 1.57 3

30” Dia. PVC -1.70 -2.39 -2.42 -2.45 1.41 1.42 1.44

4 -1.27 -1.72 -1.85 -2.07 1.35 1.46 1.63 5 -1.25 -2.56 -2.61 -2.48 2.05 2.09 1.98 6

30” Dia.

HDPE -0.80 -1.13 -1.23 -1.35 1.41 1.54 1.69 7 -0.78 -0.88 -0.90 -1.13 1.13 1.15 1.45 8 -2.53 -3.06 -3.16 -3.24 1.21 1.25 1.28 9

30” Dia.

HDPE -2.10 -2.44 -2.55 -2.46 1.16 1.21 1.17 10 -3.49 -4.73 -4.75 -4.87 1.36 1.36 1.40 11 -2.74 -3.68 -3.90 -3.35 1.34 1.42 1.22 12

30” Dia.

HDPE -1.43 -2.15 -2.27 -2.17 1.50 1.59 1.52 13 -1.36 -2.70 NA NA 1.99 NA NA 14 -2.19 -2.61 -2.33 -2.28 1.19 1.06 1.04 15

42” Dia.

HDPE -1.06 -1.85 -1.95 -1.83 1.75 1.84 1.73 16 -1.98 -2.62 -2.69 -2.60 1.32 1.36 1.31 17 -5.09 -6.07 -6.10 -5.98 1.19 1.20 1.17 18

60” Dia.

HDPE -0.84 -0.93 -0.94 -0.89 1.11 1.12 1.06 [Note] End of Construction (Dec. 1999); End of Monitoring (April 2004).

Table 4.6: Summary of Horizontal Deflection Data (Both Studies) Horizontal Deflection (%): Test

Pipe No.

Pipe Type

End of Construction

(A)

1 Year Later (B)

2 years Later (C)

5 Years Later (D)

B/A

C/A

D/A

1 0.40 0.56 0.66 0.59 1.40 1.65 1.48 2 0.80 1.11 1.33 1.49 1.39 1.66 1.86 3

30” Dia. PVC 1.21 2.27 2.28 2.28 1.88 1.88 1.88

4 0.75 0.94 0.95 0.89 1.25 1.27 1.19 5 0.86 2.20 2.43 2.22 2.56 2.83 2.58 6

30” Dia.

HDPE 0.98 1.77 1.80 1.81 1.81 1.84 1.85 7 0.09 0.15 0.14 0.13 1.67 1.56 1.44 8 0.60 0.64 0.53 0.49 1.07 0.88 0.82 9

30” Dia.

HDPE 0.58 1.13 1.05 1.18 1.95 1.81 2.03 10 2.35 2.98 2.97 2.99 1.27 1.26 1.27 11

30” Dia. 1.24 1.58 1.58 1.54 1.27 1.27 1.24

50

12 HDPE 0.63 0.67 0.58 0.62 1.06 0.92 0.98 13 0.27 0.54 NA NA 2.00 NA NA 14 0.69 0.66 0.62 0.68 0.96 0.90 0.99 15

42” Dia.

HDPE 0.28 0.38 0.30 0.48 1.36 1.07 1.71 16 0.59 0.23 0.20 0.43 0.39 0.34 0.73 17 1.26 1.19 1.18 1.18 0.94 0.94 0.94 18

60” Dia.

HDPE 0.09 -0.08 -0.17 -0.12 -0.89 -1.89 -1.33

Table 4.7: Summary of Vertical to Horizontal Deflection Ratio Data |Vertical/Horizontal| Deflection Ratio: Test

Pipe No.

Pipe Type

End of Construction

1 Year Later 2 years Later 5 Years Later

1 2.03 1.54 1.58 2.00 2 2.19 1.91 1.78 1.84 3

30” Dia. PVC 1.40 1.05 1.06 1.07

4 1.69 1.83 1.95 2.33 5 1.45 1.16 1.07 1.12 6

30” Dia.

HDPE 0.82 0.64 0.68 0.75 7 86.67 5.87 6.43 8.69 8 4.22 4.78 5.96 6.61 9

30” Dia.

HDPE 3.62 2.16 2.43 2.08 10 1.49 1.59 1.60 1.63 11 2.21 2.33 2.47 2.18 12

30” Dia.

HDPE 2.27 3.21 3.91 3.50 13 5.04 5.00 NA NA 14 3.17 3.95 3.76 3.35 15

42” Dia.

HDPE 3.79 4.87 6.50 3.81 16 3.36 11.39 13.45 6.05 17 4.04 5.10 5.17 5.07 18

60” Dia.

HDPE 9.33 11.63 5.53 7.42 [Note] End of Construction (Dec. 1999); End of Monitoring (April 2004).

Table 4.8: Summary of Circumferential Shortening Data (Both Studies) Circumferential Shortening (%): Test

Pipe No.

Pipe Type

End of Construction

(A)

1 Year Later (B)

2 years Later (C)

5 Years Later (D)

B/A

C/A

D/A

2 -0.05 --- -0.07 -0.07 --- 1.40 1.40 5

30” Dia. PVC -0.058 -0.10 -0.13 -0.38 1.72 2.24 6.47

7 -0.21 -0.29 -0.44 -0.29 1.38 2.10 1.38 8 -0.51 -0.81 -1.00 -0.82 1.59 1.96 1.61 9

30” Dia. HDPE

-0.25 -0.27 -0.25 -0.35 1.08 1.00 1.40 10 -0.30 -0.61 -0.51 -0.58 2.03 1.70 1.93 11 -0.40 -0.60 -0.64 -0.69 1.50 1.60 1.73 12

30” Dia. HDPE

-0.20 -0.34 -0.31 -0.33 1.70 1.55 1.65 14 42” HDPE -0.72 -0.83 -0.84 -0.86 1.15 1.17 1.19 17 60” HDPE -1.97 -1.68 -1.70 -1.70 0.85 0.86 0.86

[Note] End of Construction (Dec. 1999); End of Monitoring (April 2004).

51

According to these tables, PVC pipes installed in the sandy backfill (Test Pipe

Nos. 1 and 4) exhibited the following characteristics:

• Vertical deflection increased by 46 to 63% (average 55%) over the 5-year

period beyond the end of construction.

• Horizontal deflection increased by 19 to 48% (average 34%) over the 5-year

monitoring period beyond the end of construction.

• The vertical to horizontal deflection ratio ranged between 1.5 and 2.3 (average

1.9) over the 5-year period.

PVC pipes installed in the crushed rock backfill (Test Pipe Nos. 2, 3, 5, and 6) exhibited

the following characteristics:



• Horizontal deflection increased by 85 to 88% (average 86%; excluding Test

Pipe No. 5) over the 5-year monitoring period beyond the end of construction.

• The vertical to horizontal deflection ratio ranged between 0.6 and 2.2 (average

1.3) over the 5-year period.

HDPE pipes installed in the sandy backfill (Test Pipe Nos. 7, 8, 10, 13, 14, and 18)

exhibited the following characteristics:

52



• Horizontal deflection increased by -18 to 44% (average 13%; excluding Test

Pipe No. 18) over the 5-year monitoring period beyond the end of

construction.

• The vertical to horizontal deflection ratio ranged between 1.5 and 11.7

(average 4.8; excluding Test Pipe No. 7) over the 5-year period.

• The circumferential shortening increased by 19 to 93% (average 53%) over

the 5-year period.

HDPE pipes installed in the crushed rock backfill (Test Pipe Nos. 9, 11, 12, 15, 16, and

17) exhibited the following characteristics:



• Horizontal deflection increased by -27 to 71% (average 12%; excluding Test

Pipe No. 9) over the 5-year monitoring period beyond the end of construction.

• Vertical to horizontal deflection ratio ranged between 2.1 and 6.5 (average

3.5; excluding Test Pipe No. 16) over the 5-year period.

• The circumferential shortening increased by -14 to 73% (average 41%) over

the 5-year period.

53

4.3 REGRESSION ANALYSIS

In addition, the pipe deflections are plotted against time in Figures B.1 through B.36 in

Appendix B. Various curve fitting techniques (including the linear, higher-degree

polynomial, logarithmic, power law, and exponential functions) were applied to these

plots in an attempt to identify a mathematical function that best describes the changes in

the test pipes’ deflections over time. In the end, the logarithmic function, having a form

of y = a*Ln(x) + b, emerged as the most suitable function to represent the long-term

trend of the field deflection data. Table 4.9 summarizes the outcome of the numerical

analysis. In the table, the coefficient of determination (r2) values higher than 0.5 are

highlighted in bold. The value of parameter a, which reflects the time rate of pipe

deflection increase, varied from – 0.62 to – 0.04 (- 0.24 ave.) for the vertical deflections

of the PVC pipes and from – 0.45 to – 0.01 (- 0.18 ave.) for the vertical deflections of the

HDPE pipes. The parameter a value ranged from – 0.06 to + 0.66 (0.25 ave.) for the

horizontal deflections of the PVC pipes and from – 0.13 to + 0.16 (0.01 ave.) for the

horizontal deflections of the HDPE pipes.

Table 4.9: Summary of Long-Term Pipe Deflection Numerical Analysis Long-Term Vertical Deflection Long-Term Horizontal Deflection Test

Pipe Pipe Type a b r2 a b r2

1 - 0.1676 0.3106 0.5209 0.1105 - 0.5600 0.6258 2 - 0.4166 0.5562 0.8307 0.3405 - 1.2617 0.8347 3

30” Dia. PVC - 0.0837 - 1.6507 0.5822 0.1988 0.7274 0.8416

4 - 0.0386 - 1.2057 0.6279 - 0.0584 0.9688 0.1142 5 - 0.6230 1.9653 0.7854 0.6568 - 2.4845 0.7734 6

30” Dia. PVC - 0.1198 - 0.0766 0.5478 0.2208 - 0.0713 0.5837

7 - 0.0749 - 0.0111 0.3948 - 0.0292 - 0.6670 0.6628 8 - 0.1098 - 2.1595 0.3920 - 0.1252 0.7275 0.7920 9

30” Dia.

HDPE - 0.0448 - 1.8077 0.3725 0.0774 0.6343 0.5350 10 - 0.3577 - 2.1372 0.6872 0.1580 1.364 0.8285 11 - 0.1544 - 2.5058 0.5191 0.0732 0.5626 0.8379 12

30” Dia.

HDPE - 0.1264 - 0.6281 0.8711 - 0.0068 0.3967 0.0537

54

13 - 0.4500 0.9812 0.9503 0.0940 - 0.5329 0.4670 14 - 0.0683 - 1.2488 0.1991 - 0.0150 0.2424 0.1275 15

42” Dia.

HDPE - 0.0956 - 0.6932 0.4674 0.0139 - 0.2924 0.0565 16 - 0.4210 1.2724 0.9458 - 0.0322 - 0.7311 0.2475 17 - 0.2708 - 4.0002 0.9105 - 0.0193 0.9039 0.2925 18

60” Dia.

HDPE - 0.0102 0.1380 0.0935 - 0.0560 - 0.6340 0.7502 [Note] Deflection (%) = a*Ln(time in days) + b

Based on the results of the logarithmic regression analysis, the future trends of the

vertical deflection behaviors of the test pipes can be predicted by simply extending the

logarithmic functions. Figures 4.19 through 4.21 show the predictions, which indicate

that the vertical deflections of all of the pipes should grow at increasingly smaller rates.

During the 100-year period, the majority of the pipes will likely experience vertical

deflections of less than -5.0%, and none of the pipes will most likely experience vertical

deflection exceeding -7.5%.

-7.5

-5

-2.5

0

0 20 40 60 80 100

Time (years)

Ver

tical

Def

lect

ion

(%)

Pipe 1 Pipe 2 Pipe 3Pipe 4 Pipe 5 Pipe 6

Figure 4.19: 100-Year Vertical Deflections (Test Pipes 1 – 6)

55

-7.5

-5

-2.5

0

0 20 40 60 80 100

Time (years)

Ver

tical

Def

lect

ion

(%)



-7.5

-5

-2.5

0

0 20 40 60 80 100

Time (years)

Ver

tical

Def

lect

ion

(%)



The data from this study were also used to develop a best-fit multi-variable

regression equation for estimating the deflection of thermoplastic pipes under deep burial

conditions. Explanatory variables considered included: applied pressure, pipe diameter,

soil modulus, pipe moment of inertia, pipe wall area, short- and long-term pipe modulus,

56

calculated short- and long-term pipe stiffness, and time. The dependent variables

considered included horizontal and vertical deflection. For this study, the deflections

considered were both the net and the gross deflection. The net deflection is the reduction

(or increase for horizontal deflection) in the crown of the pipe measured from the

unloaded state. The gross deflection is the reduction (or increase for horizontal

deflection) in the crown of the pipe measured from the peaked position; it is the sum of

the net deflection and the peaking.

A curve fitting algorithm was utilized to determine the suitability of standard

curve models. The standard models did not provide suitable explanation of the dependent

variable by the independent variables. Additionally, two custom model expressions were

utilized for the regression analysis. The first was a formulation based on the classic

Modified Iowa Equation. This model resulted in a relatively poor ability to account for

the variability in either of the dependent variables. The second was a general polynomial

of the form:

kigec DjEhPSfTdPbaVD •+•+•+•+•+= '

(4.1)

where VD = vertical deflection (inches); P = geostatic earth pressure (psi); T = time since

installation (days); PS = calculated pipe stiffness (psi); E’= uniaxial constrained soil

modulus (psi); D = pipe diameter (inches).

57

This model showed the most promise in determining a predictive equation. A

hierarchical nonlinear regression was conducted using the explanatory variables

discussed above. The results of the regression are an equation of the form:

DEPSTPVD 0012.0'00647.0000442.0000115.0093.0869.0 69.0975.0 −−−++=

(4.2)

For this equation, the coefficient of determination, R2, is 0.67. This value is the

proportion of the variability in the data set that can be explained by the regression

equation. This indicates that there may be other explanatory variables that were not

considered in this analysis or it may be the natural variability of the system.

For the following discussion it is necessary to indicate that downward vertical

deflections were considered to be positive values. This data transformation was

necessary because many of the standard models cannot result in a negative value. In

order to assess the suitability of this equation, descriptive statistics were calculated for the

residuals. The residuals are calculated as the difference between the actual vertical

deflection and the vertical deflection predicted by the regression equation. The minimum

residual is -0.99, the maximum residual is 1.65, the mean of the residuals is 0.0003, and

the standard deviation is 0.422. This indicates that the distribution is right skewed, and

the equation will tend to overpredict the vertical deflection. It also indicates that the

equation has a limited ability to predict vertical deflections. A standard deviation of

0.422 indicates that approximately 90% of the residuals will be between -0.844 and

0.844. An error of 0.844 inches (21.4 mm) for a 42-inch (1,067-mm) diameter pipe is

58

equivalent to 2% deflection and for a 24-inch (610-mm) diameter pipe this is 3.5%

deflection. It is important to note that use of the regression equations, with input outside

the limits of the explanatory variables used in the regression analysis, can lead to

unexpected results.

4.4 LONG-TERM SOIL PRESSURE READINGS

Figures 4.22 through 4.41 plot the soil pressure cell readings against the time elapsed

since the initial pipe installation. For most test pipes, the data consisted only of the

vertical soil pressure measured at the crown and the lateral soil pressure measured at the

springline. For two test pipes (Test Pipes 2 and 11), additional pressure cell readings

were available to plot the vertical soil pressure measured at the springline and the vertical

soil pressure below the invert.

0

5

10

15

20

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

Cov

er (f

t)

Crown Springline Cover (ft)

Figure 4.22: Soil Pressures Measured Around Test Pipe 1

59

0

10

20

30

40

50

60

70

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Crown Springline 1 (hori. Gaug) Springline 2 (hori. Non.) Cover (ft)


0

5

10

15

20

25

30

35

40

45

50

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Springline 3 (Vert. Gaug) Springline 4 (Vert. Non.) Invert Cover (ft)

Figure 4.24: Additional Soil Pressure Measurements Taken for Test Pipe 2

60

0

5

10

15

20

25

30

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Springline Crown Cover (ft) Figure 4.25: Soil Pressures Measured Around Test Pipe 3

0

5

10

15

20

0 100 200 300 400 500 600 700 800 900 1000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Crown Springline Cover


61

0

5

10

15

20

25

30

35

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Crown 1 (Red) Springline Cover (ft)


0

5

10

15

20

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Springline Crown Cover (ft) Figure 4.28: Soil Pressures Measured Around Test Pipe 6

62

0

2

4

6

8

10

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Springline Crown Cover


0

5

10

15

20

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Springline Crown 1 Cover Figure 4.30: Soil Pressure Measured Around Test Pipe 8

63

0

5

10

15

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Springline Crown Cover Figure 4.31: Soil Pressure Measured Around Test Pipe 9

0

5

10

15

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)



64

0

10

20

30

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Springline 1 (vert. Gaug) Crown (Red) Cover Figure 4.33: Soil Pressure Measured Around Test Pipe 11

0

5

10

15

20

25

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Springline 1 (vert. Gaug) Springline 2 (vert. Non.) Cover

Figure 4.34: Additional Soil Pressure Measurements Taken for Test Pipe 11

65

0

5

10

15

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)

Springline Crown Cover Figure 4.35: Soil Pressures Measured Around Test Pipe 12

0

5

10

15

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)



66

0

5

10

15

20

0 200 400 600 800 1000 1200 1400

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)

Springline (Blue) Crown (Red) cover (ft) Figure 4.37: Soil Pressures Measured Around Test Pipe 14

0

5

10

15

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)


67

0

5

10

15

20

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)


0

5

10

15

20

25

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

30

35

40

45

Cov

er (f

t)



68

0

1

2

3

4

5

6

7

8

9

10

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Elapsed Time (days)

Pres

sure

(psi

)

-5

0

5

10

15

20

25

Cov

er (f

t)


4.5 FURTHER COMMENTS

With the measured soil pressure widely fluctuating during the long-term monitoring

period, the pressure ratio between the end of construction or the end of the initial

monitoring period and any subsequent time cannot be determined easily. Examinations

of these figures show that the valleys contained in the pressure vs. time curves are

approximately 400 days apart. The peaks are also spaced approximately 400 days apart

along the curves. This observation suggests that the soil pressures were most likely

undergoing seasonal changes. Both the moisture content of the embankment soil and the

temperature of the pipe material are believed to go through seasonal cycles in each year.

Extended collection and detailed analysis of environmental data are needed to prove this

point and establish the correlation between the soil pressure magnitude and the pipe

69

temperature/soil moisture. In the current project, no environmental instrumentations

existed at the field test site. The resistance readings of the soil pressure cell transducers

did provide the temperature fluctuations in the field. However, these readings showed

changes in the temperature of the soil surrounding the pipe, not of the pipes. A set of

analysis is presented in Appendix C to show the correlations between the soil pressure

measurements and the temperature recorded in the soil surrounding the test pipes.

The long-term pipe deflection behaviors shown in Figures 4.1 through 4.18 do not

appear to exhibit the same type of seasonal fluctuations as that of the long-term soil

pressure behaviors plotted in Figures 4.22 through 4.41. A similar set of data analysis is

presented in Appendix D to show if any meaningful correlations existed between the pipe

deflections and the temperature recorded in the soil surrounding the test pipes.

Some theoretical considerations are given in Appendix E to gain insights into the

probable effects of environmental factors on buried pipe performances. The authors

decided to treat all these extra data analyses outside the main part of the report, since the

actual temperatures of the pipe materials were not available in the study.

4.6 IN-SITU PIPE NOTCHING EXPERIMENTS

The in-situ pipe notching experiments were carried out at the deep burial project site in

the fall of 2004. Test Pipes 6 (30-inch or 762-mm diameter PVC pipe), 12 (30-inch or

762-mm diameter HDPE pipe), 15 (42-inch or 1,067-mm diameter HDPE pipe) were

utilized in the experiments. The field experiment proceeded for each of the pipes as

follows:

70

• Installation of electrical resistance strain gages (type KFG-5-120-D16-

11L3M3S by Kyowa Dengyo Kenkyujo, Japan) both in the circumferential

and longitudinal directions at the crown and springline locations, at a pipe

cross section located 50 ft (15.2 m) away from the end of the pipeline

• Notching (0.1-inch or 2.5-mm depth x 2-inch or 51-mm length) of the pipe

wall material with a sharp knife very close to each strain gage location

• Recording of the strain gage reading before, during, and after the pipe wall

notching.

Figure 4.42 illustrates the strain gage and notching locations. The actual

photographs taken during the field experiments are shown in Figures 4.43 and 4.44. The

strain gage readings recorded during each experiment are presented in Figures 4.45

through 4.56.

Figure 4.42: Locations of Cuts and Strain Gages

71

Figure 4.43: Notch #2 in Crown Region by Strain Gages #3 and #4

Figure 4.44: Notch #3 in Springline Region by Strain Gages #5 and #6

72

Figure 4.45: Strain Gage Responses to Introduction of Notch #1 (Test Pipe 15)


73



74

Cut EHDPE Pipe #12

0

200

400

600

800

1000

1200

1400

0 2 4 6 8 10 12 14 16 18

Time (sec)

Stra

in (u

e)

DYN-001 ueDYN-002 ue


Cut F HDPE Pipe #12

0

500

1000

1500

2000

2500

0 2 4 6 8 10 12

Time (sec)

Stra

in (u

e)



75

CUT G HDPE Pipe #12

-1000

-500

0

500

1000

1500

2000

2500

3000

3500

4000

0 2 4 6 8 10 12

Time (sec)

Stra

in (u

e)



CUT H HDPE Pipe #12

-1500

-1000

-500

0

500

1000

1500

2000

2500

3000

3500

0 2 4 6 8 10 12 14 16 18

Time (sec)

Stra

in (u

e)



76

CUT A PVC Pipe #6

-300

-200

-100

0

100

200

300

400

500

600

700

800

0 2 4 6 8 10 12

Time (sec)

Stra

in (u

e)



CUT B PVC Pipe #6

-500

-400

-300

-200

-100

0

100

200

300

400

0 2 4 6 8 10 12

Time (sec)

Stra

in (u

e)



77

CUT C PVC Pipe #6

-200

0

200

400

600

800

1000

1200

0 2 4 6 8 10 12 14

Time (sec)

Stra

in (u

e)



CUT D PVC Pipe #6

0

200

400

600

800

1000

1200

0 1 2 3 4 5 6 7 8 9 10

Time (sec)

Stra

in (u

e)



78

The notching method applied in the field was borrowed from the laboratory

notched constant tensile load (NCTL) test protocol, ASTM D 5397. Based on the above

plots, the following observations can be made:

• The sharp knife cut (a form of notching) introduced to the interior surface of

the wall section of the buried HDPE pipe induced strains instantaneously

within in the close vicinity of the cut.

• In most cases, the magnitudes of strains induced within the wall were less than

1,000 micro-strains (or 0.1%).

• In most cases, the strains induced through the notching dissipated completely

within 10 seconds.

• None of the cuts made into the pipe wall surface exhibited slow crack growth

behavior. This aspect was especially significant for the longitudinal cuts

made into the interior pipe wall surface in the crown region, where tensile

stresses often exist.

• Overall, the field notching experiment results showed that the field behaviors

of the buried thermoplastic pipe are governed more by stress relaxation than

by creep for the size of the defects tested.

4.7 LABORATORY COUPON TESTING

A small piece of the pipe wall section was sawed off from the end section of Test Pipes

12, 15, and 16 on Sept. 15, 2006. A series of tensile strength testing were conducted in

the laboratory using coupon specimens cut out from the test pipes, vise grips, and a

79

computerized loading system. All the tests were performed in accordance to ASTM D-

638 method. The HDPE pipe material was classified as Type IV (semi-rigid) material.

Thus, the test specimen had to have the dimensions shown in Figure 4.57 and 4.59 and be

loaded at a constant rate of 2 inches/minute (50 mm/minute) to failure at standard

laboratory atmosphere of 23 + 2 °C. The typical test set-up is shown in Figure 4.58

below.

Figure 4.57: Trimming of Circumferential Direction Coupons

80

Figure 4.58: Typical Test Set-up for Tensile Strength Test

Figure 4.59: Coupon Specimens Before and After Test

81

Figure 4.60: Elongation of Coupon during Tensile Strength Test

0

1000

2000

3000

4000

5000

0 20 40 60 80 100 120

Axial Strain (%)

Axi

al S

tress

(psi

)

Figure 4.61: Typical Stress-Strain Plot from Tensile Strength Test

82

The test results are tabulated for selected HDPE pipe materials in Table 4.10.

Figure 4.61 above presents the stress vs. strain plot produced from one of the actual tests.

According to AASHTO M-294, ultimate strength should be between 3,000 and 3,500 psi

(20.7 and 24.1 MPa). According to ASTM D-3350 and AASHTO M-294 & M-252, the

yield strength requirement depends on the cell class (see Table 4.11).

Table 4.10: Summary of Tensile Strength Test Results Key Test Results: Test

Pipe No.

Coupon Material Type & Orientation

Specimen Age

(years) Ultimate Strength

(psi) Elongation @

Break (%)

Test Temp. (°C)

HDPE - Circumferential 3,406.0 74.3 12 HDPE - Circumferential

Approx. 7 3,848.9 62.9

22


Approx. 7 4,177.5 148.8

22


Approx. 7 4,130.1 118.5

22

[Note] 1 psi = 6.9 kPa.

Table 4.11: Yield Strength Requirements Based on Cell Class Cell Class: Property

1 2 3 4 5 Density (g/cm3) 0.91 to 0.925 0.925 to

0.940 0.940 to

0.947 0.947 to

0.955 > 0.955

Tensile Yield Strength (psi)

< 2,200 2,200 to 2,600

2,600 to 3,000

3,000 to 3,500

3,500 to 4,000

Based on the test results summarized in Table 4.10 and the regulatory

requirements, it appears that the HDPE pipe material has not degraded at all over the

seven year period in which the pipes were exposed to weather elements and loading.

4.8 PIPE WALL BUCKLING TESTS

No test results can be reported at this time, as the test equipment was not available to the

ORITE researchers prior to the time of preparing this report.

83

4.9 ADDITIONAL INFORMATION

One of the objectives of the current research project was to evaluate the integrity of the

pipe joints. Visual inspection of the pipe joints was made in selected test pipes by the

ORITE team when the long-term performance data were collected in the field. The

visual inspections detected no measurable movements (opening, offsets) and no structural

problems (cracks, buckling) at any of the joints. No signs of backfill infiltration were

observed at any of the pipe joints existing at the site. To support this conclusion, Figures

4.62 through 4.65 are attached here to present the overall integrity of the pipe joint

sections as observed during the fall of 2006.

Figure 4.62: General View of Pipe Joint Section Inside Test Pipe 6

84


Figure 4.64: Pipe Joint Section Inside Test Pipe 15

85


87

CHAPTER 5: SUMMARY AND CONCLUSIONS

5.1 SUMMARY

The ORITE performed a comprehensive field study of deeply buried large-diameter

thermoplastic pipes at a field site located near Athens, Ohio between the summer of 1999

and the summer of 2002. The findings made during the initial study can be found in the

final report issued by Sargand et al. (2002). This initial study provided detailed field

performance data for thermoplastic pipe from the first one year after installation. The

plastic pipes are manufactured from thermoplastic materials, which tend to exhibit visco-

elastic behavior over time. The viscoelastic behavior, characterized by creep under

constant stress and stress relaxation under constant strain, may have significant influence

on the long-term performance of buried thermoplastic pipe. Thus, there is a need to

continue to monitor the field performance of these test pipes at the ORITE project site

beyond the initial one year.

The current project was performed to meet the following objectives:

• Determine the long-term performance of thermoplastic pipe under deep soil

cover.

• Provide data for development of cost-effective design and installation

procedures.

• Evaluate the effectiveness of the pipe joints.

• Obtain data on the slow crack growth.

88

During the current project, the research team continued to record readings from

the linear potentiometers and soil pressure cells that were installed inside/around each of

the eighteen test pipes. The field data collection took place at the project site in Albany,

Ohio over an approximately 5-year time span, from October 2000 to April 2005. In

addition, visual inspection of the pipe joints was made in selected test pipes by the

ORITE team when the long-term performance data were collected in the field.

In the current research project, coupon specimens were cut from the test pipes in

the field and subjected to tensile strength test in the laboratory to determine their tensile

modulus and strength properties, according to ASTM D-638 (type IV) method. Once the

test results were obtained, they were compared to the original material specifications to

discuss the degree of aging these test pipes experienced during the past several years.

In order to meet the last project objective, the stress crack tests were performed in

the field, utilizing some of the test pipes that were installed during the original deep

burial project. In this in-situ test procedure, first strain gages were installed at

predetermined locations within the circumferential section of each test pipe selected for

the field testing. Then, controlled physical damages were introduced to the pipe wall

surface very close to the strain gages. The readings from the strain gages were recorded

frequently over a duration of time to observe the pipe wall responses to the notching and

thus access the crack growth potential of the pipe material has in the actual field

installation environments.

89

5.2 CONCLUSIONS

5.2.1 Conclusions for Long-Term Field Performance of Deeply Buried

Thermoplastic Pipes

The long-term field performance data accumulated over the past five years in the

thermoplastic deep burial project in Ohio revealed that the pipe-soil interaction behaviors

which were rarely reported in the past. The soil pressures around the thermoplastic pipe

declined slightly over time and then underwent seasonal cyclic fluctuations in each year

while the pipe deflections remained nearly constant for a long time. Thus, the long-term

performance of buried thermoplastic pipe speculated by Petroff (1990) was basically

confirmed through the five-year data. The seasonal fluctuations in the peripheral soil

pressure were believed to be induced by environmental factors (changes in the pipe

material temperature and soil moisture), as the typical fluctuation pattern possesses peaks

and valleys that are spaced about one year apart. PVC pipes under 20 ft (6.1 m) soil

cover exhibited more pronounced seasonal soil pressure changes than the HDPE pipes

under 20 ft (6.1 m) soil cover or PVC pipes under 40 ft (12.2 m) cover. This was

somewhat surprising considering the fact that coefficient of thermal expansion (CTE) of

HDPE material is about twice as large as that of PVC material. It is believed that not

only the pipe material and size but also the pipe’s exterior surface geometry (i.e.,

corrugation spacing) in relationship to gradation characteristics of backfill soil played a

role in determining the magnitude of thermally induced soil pressure around pipe.

90

5.2.2 Conclusions from Regression Analysis of Pipe Deflection Data

Two levels of regression analysis were conducted for the long-term pipe deflection data

to identify – 1) the best mathematical function for describing the time-dependent nature

of the deflections of the deeply buried thermoplastic pipe; and 2) significant factors

impacting both the short-term and long-term pipe deflections.

In the first analysis, various curve fitting techniques (including the linear, higher-

degree polynomial, logarithmic, power law, and exponential functions) were applied to

these plots in an attempt to identify a mathematical function that best describes the

changes in the test pipes’ deflections over time. In the end, the logarithmic function,

having a form of y = a*Ln(x) + b, emerged as the most suitable function to represent the

long-term trend of the field deflection data. Based on the results of the logarithmic

regression analysis, the future trends of the vertical deflection behaviors of the test pipes

were predicted by simply extending the logarithmic functions. The trends showed that

the vertical deflections of all of the pipes would be growing at increasingly smaller rates.

During the 100-year period, the majority of the pipes will likely experience vertical

deflections of less than -5.0%, and none of the pipes will most likely experience vertical

deflection exceeding -7.5%.

In the multi-variable regression analysis considered variables such as applied

pressure, pipe diameter, soil modulus, pipe moment of inertia, pipe wall area, short- and

long-term pipe modulus, calculated short- and long-term pipe stiffness, and time. The

dependent variables were horizontal and vertical deflections. The deflections considered

were both the net and the gross deflection. The net deflection is the reduction (or

increase for horizontal deflection) in the crown of the pipe measured from the unloaded

91

state. The gross deflection is the reduction (or increase for horizontal deflection) in the

crown of the pipe measured from the peaked position; it is the sum of the net deflection

and the peaking. A curve fitting algorithm was utilized to determine the suitability of

standard curve models. The standard models did not provide suitable explanation of the

dependent variable by the independent variables. Additionally, two custom model

expressions were utilized for the regression analysis. The first was a formulation based

on the classic modified Iowa equation. This model resulted in a relatively poor ability to

account for the variability in either of the dependent variables. The second had a general

polynomial form. This model showed the most promise in determining a predictive

equation. A hierarchical nonlinear regression was conducted using the explanatory

variables discussed above. The results of the regression are an equation of the form:

DEPSTPVD 0012.0'00647.0000442.0000115.0093.0869.0 69.0975.0 −−−++=

For this equation, the coefficient of determination, R2, is 0.67. This value is the

proportion of the variability in the data set that can be explained by the regression

equation. This indicates that there may be other explanatory variables that were not

considered in this analysis or it may be the natural variability of the system.

For the following discussion it is necessary to indicate that downward vertical

deflections were considered to be positive values. This data transformation was

necessary because many of the standard models cannot result in a negative value. In

order to assess the suitability of this equation, descriptive statistics were calculated for the

92

residuals. The residuals are calculated as the difference between the actual vertical

deflection and the vertical deflection predicted by the regression equation. The minimum

residual is -0.99, the maximum residual is 1.65, the mean of the residuals is 0.0003, and

the standard deviation is 0.422. This indicates that the distribution is right skewed, and

the equation will tend to overpredict the vertical deflection. It also indicates that the

equation has a limited ability to predict vertical deflections. A standard deviation of

0.422 indicates that approximately 90% of the residuals will be between -0.844 and

0.844. An error of 0.844 inches (21.44 mm) for a 42-inch (1.1-m) diameter pipe is

equivalent to 2% deflection, and for a 24-inch (0.6-m) diameter pipe this is 3.5%

deflection.

5.2.3 Conclusions from Detailed Field Data Analysis

The long-term pipe deflection behaviors of the thermoplastic pipes did not appear to

exhibit the same type of seasonal fluctuations as those of the long-term soil pressure

behaviors mentioned above. In order to see if temperature had any influence on the pipe

deflections, the pipe deflections were plotted against the temperature registered by the

pressure cells in Appendix C. Linear regression analysis applied to these plots indicated

that the pipe deflections were likely to be influenced by the seasonal temperature

fluctuations. But, the temperature effect on the pipe deflections were less than the effect

the temperature changes had on the soil pressures around the pipe periphery. According

to the regression analysis results summarized in the above tables, in most of the cases the

temperature increase translated into an increase in the horizontal deflection and a

decrease in the vertical deflection. When the pipe type, burial depth, and the relative

93

compaction are all fixed, the linear regression coefficient value tends to be somewhat

larger for the sand backfill than the crushed limestone backfill. For either type of pipe

material, the lower the relative compaction initially achieved on the backfill is, the more

the thermally induced deflections are. Also, it appears that the deeper the burial depth is,

the less the thermally induced deflections tend to be for the same change in the

temperature.

5.2.4 Conclusions from Theoretical Analysis

A detailed theoretical analysis was carried out in Appendix D, using the full field elastic

solutions established by Burns and Richard (1964). The theoretical results yielded

somewhat larger thermally induced soil pressures for the PVC pipes than for the HDPE

pipes. This was because of the higher hoop stiffness values possessed by the PVC pipes.

For each pipe material type, the full-bond solution produced higher radial pressure

changes at the springline position than at the crown. The free-slip solution produced

slightly higher radial pressure changes at the crown than at the springline. It was also

noted here that the thermally induced changes in the radial soil pressure given by the

theoretical approach based on the full-field elastic solutions are smaller than what were

measured at the crown position for all of the pipes. The theoretical approach (with full-

bond interface) yielded reasonable results for eight out of the eighteen (44%) cases for

the radial pressure changes at the springline position.

The effect of moisture fluctuations within the embankment fill soil was also

examined using the elastic solutions in Appendix D. The elastic solutions indicate that

both soil pressure acting against buried pipe and the pipe deflections are directly

94

proportional to the vertical pressure (P) applied at the top boundary located not too far

away above the pipe. For the 20 ft (6.1 m) soil cover, the 5% increase in the moisture

content within the upper 5 ft (1.5 m) zone might have increased the P value by about

1.5%. For the 40 ft (12.2 m) soil cover, the 5% increase in the moisture content within

the upper 5 ft (1.5 m) zone might have increased the P value by about 0.7%. These

suggest that both the soil pressure and pipe deflections should fluctuate by only 0.7 to

1.5% if the moisture conditions change seasonally. The actual soil pressure fluctuations

were much larger than the range predicted here, which implies that the temperature effect

might have been more dominating than the soil moisture effect.

5.2.5 Conclusions from In-Situ Pipe Notching Experiments

The in-situ pipe notching experiments were carried out at the deep burial project site in

the fall of 2004. Test Pipes 6 (30-inch or 762-mm diameter PVC pipe), 12 (30-inch or

762-mm diameter HDPE pipe), and 15 (42-inch or 1,067-mm diameter HDPE pipe) were

utilized in the experiments. The sharp knife cut (a form of notching) introduced to the

interior surface of the wall section of the buried HDPE pipe induced strains

instantaneously within in the close vicinity of the cut. In most cases, the magnitudes of

strains induced within the wall were less than 1,000 micro-strains (or 0.1%). And, the

strains dissipated completely within 10 seconds. None of the cuts made into the pipe wall

surface exhibited slow crack growth behavior. This aspect was especially significant for

the longitudinal cuts made into the interior pipe wall surface in the crown region, where

tensile stresses often exist. Overall, the field notching experiment results showed that the

95

field behaviors of the buried thermoplastic pipe are governed more by stress relaxation

than by creep for the size of the defects tested.

5.2.6 Conclusions from Laboratory Coupon Testing

A small piece of the pipe wall section was sawed off from the end section of Test Pipes

12, 15, and 16 on Sept. 15, 2006. A series of tensile strength testing were conducted in

the laboratory using coupon specimens cut out from the test pipes, vise grips, and a

computerized loading system. All the tests were performed in accordance to ASTM D-

638 method. All of the test results indicated that the HDPE pipe material did not degrade

at all over the seven year period, in which the pipes were exposed to weather elements

and constant gravitational loading from the earth embankment.

5.2.7 Conclusions from Joint Integrity Observations

One of the objectives of the current research project was to evaluate the integrity of the

pipe joints. Visual inspection of the pipe joints was made in selected test pipes by the

ORITE team when the long-term performance data were collected in the field. The

visual inspections detected no measurable movements (opening, offsets) and no structural

problems (cracks, buckling) at any of the joints. No signs of backfill infiltration were

observed at the pipe joints existing at the site.

97

CHAPTER 6: IMPLEMENTATIONS The initial phase and the current long-term monitoring phase of the thermoplastic pipe

deep burial project conducted by the ORITE showed through a large volume of field

performance data that proper initial installation is the key in assuring the stable long-term

structural performance for the flexible thermoplastic pipe. When these pipe products are

installed with 8-inch thick (203-mm) lifts of a 96% compaction granular backfill within a

properly prepared trench, their structural performance can stabilize shortly after the end

of construction. In lieu of the above, it is viewed essential that the thermoplastic pipe be

installed:

• in a trench having stable trench walls and a minimum trench width of two

times the pipe OD or the pipe OD plus 4 ft (1.2 m), whichever is larger.

• on a bedding layer which consists of a clean granular soil, has a minimum

thickness of 8 inches (203 mm), and is only compacted outside the middle one-

third of the width.

• in the granular backfill soil so that it experiences peaking deflections on the

order of 0.2 to 05% for the PVC pipes and 1 to 2% for the HDPE pipes.

According to the long-term field data, both the soil pressure acting against the

pipe and the pipe deflections undergo seasonal fluctuations in each year. However, these

fluctuations are cyclic (not cumulative) and rather minor compared to the amount of soil

pressure or deflections that the pipe has experienced already under the gravitational

loading produced by the embankment fill. Properly installed thermoplastic pipe interacts

98

with the surrounding soil, so that its field performance is not affected by creep, wall

buckling, and wall tearing/cracking for at least five years. The quality of construction

dictates both the short-term and long-term structural performances of these flexible

thermoplastic pipe products.

With the long-term monitoring phase of the project coming to an end, a truly

comprehensive, real-world, field performance data set (presented in Appendix A) is now

available for any soil-pipe interactions researcher to test any of the existing

design/analysis methods and possibly develop improved design/analysis approaches for

the buried thermoplastic pipe structures.

99

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Chua, K. M., and Lytton, R. L. (1989). “Viscoelastic Approach to Modeling Performance

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Findley, W. N., Lai, J. S., and Onaran, K. (1989). Creep and Relaxation of Nonlinear

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Gabriel, L. H., and Goddard, J. B. (1999). “Curved Beam Stiffness for Thermoplastic

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Goddard, J. B., and Gabriel, L. H. (1999). “Curved Beam Stiffness and Profile/Wall

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78th Annual Meeting, Washington, 8+pp.

100

Howard, A. K. (1981). “The USBR Equation for Predicting Flexible Pipe Deflection.”

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Janson, L. E. (1990). “Short-Term Versus Long-Term Pipe Ring Stiffness in the Design

of Buried Plastic Sewer Pipes.” Proceedings of International Conference – Pipeline

Design and Installation, ASCE, pp. 160-167.

Ko, H-Y. (1988). “Summary of State-of-the-Art in Centrifuge Model Testing.”

Proceedings of International Symposia – Centrifuges in Soil Mechanics (in San

Francisco, CA), Balkema Publishers, Rotterdam, the Netherland, pp. 11-18.

Koerner, R. M. (1994). Designing with Geosynthetics, 3rd Edition, Prentice Hall, Upper

Saddle River, NJ, 783 pp.

Marston, A., and Anderson, A. O. (1913). “The Theory of Loads on Pipes in Ditches and

Tests of Cement and Clay Drain Tile and Sewer Pipe.” Bulletin 31, Iowa

Engineering Experiment Station, Iowa State College, Ames, Iowa, 1913.

Masada, T., and Sargand, S. M. (2005). “Peaking Deflections of Flexible Thermoplastic

Pipe.” Proceedings of Pipelines 2005 Conference, ASCE.

Moser, A. P., Bishop, R. R., Shupe, O. K., and Bair, D. R. (1985). “Deflection and

Strains in Buried FRP Pipes Subjected to Various Installation Conditions.”


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Mwanang′onze, H., and Moore, I. D. (2003). “Coefficient of Thermal Expansion

Coefficient for Plain Polyethylene Pipe.” Proceedings of Pipelines 2003 Conference,

ASCE, Volume 2, pp. 1302-1311.

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National Cooperative Highway Research Project (NCHRP) Report No. 04-24 (1999).

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Research Board, National Research Council, Washington, D.C.

Petroff, L. J. (1990). “Stress Relaxation Characteristics of the HDPE Pipe-Soil System.”

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Rogers, C. D. F. (1988). “Some Observations on Flexible Pipe Response to Load.”


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Sargand, S. M., Masada, T., and Schehl. (2001). “Soil Pressure Measured at Various Fill

Heights Above Deeply Buried Thermoplastic Pipe.” Transportation Research

Record, No. 1770, National Research Council, Washington, pp. 227-235.

Sargand, S. M., Hazen, G. A., Masada, T. (2002). “Field Verification of Structural

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2002/023, Final Report to Ohio Department of Transportation and Federal Highway

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Sargand, S. M., Masada, T., White, K. E., and Altarawneh, B. (2002). “Profile-Wall

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Sargand, S. M., Masada, T., White, K. E., and Altarawneh, B. (2003a). “Soil Arching

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103

APPENDIX A:

SOIL PRESSURE & PIPE DEFLECTION DATA

104

It is important to note that the pipe deflection values appearing in Chapter 3 and Appendix A of this report are compatible. The pipe deflections presented in Chapter 3 are all computed with respect to the vertical and horizontal diameters the pipes had at the end of the initial backfilling stage (when the soil cover height was 1 ft over the crown). Please see the statement about this on page 21 (Section 3.2.2 – Pipe Deformations). This arrangement was made in Chapter 3 to address the long-term effect of the embankment loading only on the pipe deflection behaviors. In contrast, the pipe deflections listed in the Appendix A tables are all computed with respect to the initial shapes they had prior to the backfill soil placement (before placing the first lift of backfill). This arrangement was made in Appendix A to maintain continuity in the deflection data all through the different stages of construction and beyond. The following example shows how the pipe deflection values are compatible between Chapter 3 and Appendix A. According to Appendix A, deflections experienced by Test Pipe 1 were: Nov. 23 (10:40 a.m.), 1999 (No Backfilling Placed) Pipe Deflections = 0.000% (Vertical); 0.000% (Horizontal) Nov. 23 (3:50 p.m.), 1999 (Soil Cover = 1.0 ft End of Initial Backfilling) Pipe Deflections = + 0.278% (Vertical); - 0.429% (Horizontal) Dec. 22, 1999 (Soil Cover = 20.2 ft End of Construction) Pipe Deflections = - 0.527% (Vertical); - 0.032% (Horizontal) April 12, 2000 (3 to 4 Months After Construction) Pipe Deflections = - 0.655% (Vertical); + 0.061% (Horizontal) July 24, 2000 (End of Initial Phase) Pipe Deflections = - 0.578% (Vertical); + 0.064% (Horizontal) Thus, if we use the shape this pipe had at the end of the initial backfilling stage as the initial shape, then the deflections this pipe had at the end of construction are computed as: Vertical Deflection = - 0.527 – 0.278 = - 0.805% Horizontal Deflection = - 0.032 – (-0.429) = + 0.397% Similarly, the deflections this pipe had 3 to 4 months after construction are computed as: Vertical Deflection = - 0.655 – 0.278 = - 0.933% Horizontal Deflection = 0.061 – (-0.429) = + 0.490% Similarly, the deflections this pipe had at the end of the initial phase are computed as: Vertical Deflection = - 0.578 – 0.278 = - 0.856% Horizontal Deflection = 0.064 – (-0.429) = + 0.493%

105

These three sets of computed deflections values are basically the same as those reported for Test Pipe 1 in Chapter 3 at the end of construction, 3 to 4 months after construction, and at the end of the initial phase study.

Test Pipe #1 (30-in dia. PVC pipe backfilled in sand; 96.2% relative compaction) Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 49734 (G = 0.022486; K = - 0.000926)

Cell Readings Pipe Deflection (%) + Date & Time

Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Cell Temp. (°C)

Vertical Horizon.

11-23-99 10:40 0.0 - 0.7 9,155 5,710 0.00 10.87 0.000 0.000 11-23-99 12:30 0.1 0.0 9,122 3,900 0.73 19.06 0.325 -0.444 11-23-99 14:05 0.1 0.5 9,126 4,260 0.65 17.13 0.279 -0.429 11-23-99 15:50

* 0.2 1.0 9,106 4,080 1.10 18.07 0.278 -0.429

12-02-99 7:45 8.9 3.0 9,040 6,770 2.59 7.34 0.108 -0.360 12-08-99 6:50 14.8 5.6 8,938 6,740 4.88 7.43 -0.099 -0.238 12-09-99 8:36 15.9 7.9 8,878 6,890 6.23 6.98 -0.172 -0.194

12-09-99 15:30 16.2 10.1 8,850 6,700 6.86 7.55 NA NA 12-16-99 15:55 23.2 12.3 8,819 6,830 7.56 7.16 NA NA 12-20-99 8:20 26.9 13.5 8,779 6,530 8.46 8.08 -0.267 -0.158 12-21-99 8:30 27.9 15.3 8,776 6,710 8.53 7.52 -0.332 -0.115

12-21-99 15:04 28.2 16.6 8,757 6,780 8.95 7.31 -0.389 -0.109 12-22-99 16:15

** 29.2 20.2 8,710 6,880 10.01 7.01 -0.527 -0.032

12-29-99 10:40 36.0 20.2 8,681 7,270 10.66 5.89 -0.596 0.029 01-07-00 10:55 45.0 20.2 8,663 6,900 11.07 6.95 -0.588 0.095 03-15-00 14:22 114.0 20.2 NA NA NA NA -0.660 0.079 04-12-00 12:00 141.1 20.2 8,585 6,370 12.82 8.60 -0.655 0.061

05-22-00 180.6 20.2 8,566 5,780 13.24 10.62 -0.673 0.007 06-19-00 208.6 20.2 8,492 5,100 14.91 13.26 -0.591 0.077

07-24-00 *** 243.6 20.2 8,497 5,150 14.79 13.05 -0.578 0.064 10-23-00 334.6 20.2 8,492 5,000 14.91 13.68 -0.580 0.0549 12-11-00 383.6 20.2 8,566 5,780 13.24 10.62 NA NA 02-07-01 441.6 20.2 8,567 6,420 13.22 8.43 -0.714 0.088 04-12-01 505.6 20.2 8,614 5,320 12.16 12.36 -0.598 0.060 06-14-01 568.6 20.2 8,609 5,240 12.28 12.68 -0.586 0.017 01-29-02 797.6 20.2 8,579 5,670 12.95 11.02 -0.764 0.154 06-21-02 940.6 20.2 8,528 5,150 14.10 13.05 -0.766 0.228 04-09-03 1,232.6 20.2 8,617 5,940 12.10 10.05 -0.866 0.199 04-28-04 1,617.6 20.2 8,597 5,910 12.55 10.15 -1.217 0.391 04-01-05 1,955.6 20.2 8,609 5,930 12.28 10.08 NA NA

[Notes] “NA” = Data Not Available * End of Initial Backfilling ** End of Embankment Construction *** End of Initial Monitoring Phase

+ Pipe deflections are all relative to the initial shape the pipe had at the beginning of the initial backfilling process.

106

Test Pipe #1 (30-in dia. PVC pipe backfilled in sand; 96.2% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 49730 (G = 0.025967; K = 0.004321)


Days

Cover (ft) VW-

f2 Resistance (Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-23-99 08:00 0.0 - 2.0 8,771 6,920 0.00 6.89 0.000 0.000 11-23-99 09:10 0.0 - 1.3 8,764 6,460 0.19 8.31 0.089 -0.239 11-23-99 10:40 0.1 - 0.7 8,752 6,330 0.50 8.73 0.227 -0.385 11-23-99 12:30 0.2 0.0 8,756 6,050 0.40 9.66 0.324 -0.444 11-23-99 14:05 0.3 0.5 8,741 5,610 0.80 11.24 0.279 -0.429 11-23-99 15:50

* 0.3 1.0 8,735 5,500 0.96 11.66 0.278 -0.429

12-02-99 7:45 9.0 3.0 8,709 6,390 1.62 8.53 0.108 -0.360 12-07-99 15:10 14.3 4.5 8,663 6,130 2.82 9.39 NA NA 12-08-99 6:50 15.0 5.6 8,649 6,130 3.18 9.39 -0.099 -0.238

12-08-99 15:30 15.3 5.9 8,615 6,310 4.06 8.79 -0.127 -0.217 12-09-99 8:36 16.0 7.9 8,595 6,460 4.58 8.31 -0.172 -0.194

12-09-99 15:30 16.3 10.1 8,577 6,200 5.05 9.16 NA NA 12-13-99 16:00 20.3 10.1 8,549 6,000 5.78 9.84 NA NA 12-16-99 15:55 23.3 12.3 8,507 6,410 6.86 8.47 NA NA 12-20-99 8:20 27.0 13.5 8,468 6,040 7.88 9.70 -0.267 -0.158 12-21-99 8:30 28.0 15.3 8,440 6,420 8.60 8.43 -0.332 -0.115

12-21-99 15:04 28.3 16.6 8,408 6,460 9.43 8.31 -0.389 -0.109 12-22-99 16:15

** 29.2 20.2 8,312 6,530 11.92 8.08 -0.527 -0.032

12-29-99 10:41 36.1 20.2 8,310 7,050 11.97 6.51 -0.596 0.029 01-07-00 10:55 45.1 20.2 8,318 6,670 11.77 7.65 -0.588 0.095 03-15-00 14:22 114.0 20.2 NA NA NA NA -0.660 0.079 04-12-00 12:00 141.2 20.2 8,273 6,210 12.94 9.12 -0.655 0.061

05-22-00 180.7 20.2 8,274 5,680 12.92 10.98 -0.673 0.007 06-19-00 208.7 20.2 8,244 5,060 13.71 13.43 NA NA

07-24-00 *** 243.6 20.2 8,263 5,140 13.22 13.09 -0.578 0.064 10-23-00 334.7 20.2 8,246 5,080 13.66 13.34 -0.580 0.055 12-11-00 383.7 20.2 8,275 5,860 12.89 10.33 NA NA 02-07-01 441.7 20.2 8,262 6,470 13.22 8.27 -0.714 0.088 04-12-01 505.7 20.2 8,308 5,220 12.05 12.76 -0.598 0.060 06-14-01 568.7 20.2 8,394 5,270 9.81 12.56 -0.586 0.017 01-29-02 797.7 20.2 8,303 5,660 12.17 11.06 -0.764 0.154 06-21-02 940.7 20.2 8,280 5,120 12.78 13.17 -0.766 0.228 04-09-03 1,232.7 20.2 8,348 5,780 11.00 10.62 -0.901 0.077 04-28-04 1,617.7 20.2 8,361 5,970 10.66 9.94 -1.217 0.391 04-01-05 1,955.7 20.2 8,377 5,840 10.25 10.40 NA NA

[Notes] “NA” = Data Not Available. * End of Initial Backfilling ** End of Embankment Construction *** End of Initial Monitoring Phase


107

Test Pipe #2 (30-in dia. PVC pipe backfilled in crushed limestone; 101.0% relative compaction)

Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 45292 (G = 0.024381; K = - 0.02616)


Days

Cover

(ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-22-99 14:57 --- -2.67 --- --- --- --- 0.000 0.000 11-23-99 10:40 0.0 -0.67 8,852 5,240 0.00 12.68 0.147 -0.284 11-23-99 12:30 0.1 0.0 8,815 3,420 0.66 21.98 0.187 -0.311 11-23-99 14:05 0.1 0.5 8,825 4,180 0.53 17.54 0.116 -0.265 11-23-99 15:50

* 0.2 1.0 8,799 4,290 1.18 16.98 0.071 -0.238

12-03-99 7:50 9.9 3.0 8,773 6,540 2.05 8.05 -0.158 -0.138 12-08-99 15:36 15.2 6.27 8,670 6,640 4.57 7.74 -0.295 -0.026 12-09-99 8:40 15.9 7.85 8,666 6,690 4.67 7.59 -0.301 -0.017

12-09-99 15:43 16.2 10.24 8,657 6,610 4.88 7.83 -0.317 0.038 12-16-99 8:40 22.9 11.96 8,645 6,700 5.18 7.55 NA NA

12-17-99 15:10 24.2 14.98 8,587 6,650 6.59 7.71 -0.558 0.089 12-20-99 17:48 27.3 16.77 8,544 6,380 7.62 8.56 -0.554 0.070 12-21-99 16:21 28.2 18.58 8,526 6,550 8.07 8.02 -0.592 0.081 12-22-99 8:00 28.9 20.14 8,492 6,500 8.90 8.18 -0.687 0.125

12-22-99 16:22 29.2 22.35 8,459 6,660 9.71 7.68 -0.713 0.117 12-23-99 8:47 29.9 23.11 8,431 6,630 10.39 7.77 -0.770 0.138 12-24-99 8:00 30.9 27.67 8,370 6,500 11.87 8.18 -1.078 0.306

12-27-99 16:05 34.2 32.34 8,335 6,740 12.74 7.43 -1.109 0.334 12-28-99 9:20 34.9 38.33 8,261 6,640 14.54 7.74 -1.361 0.407

12-29-99 10:42 **

36.0 40.00 8,211 6,890 15.78 6.98 NA NA

01-07-00 10:54 45.0 40.00 8,111 6,600 18.19 7.86 -1.682 0.564 04-12-00 12:00 141.1 40.00 8,075 6,240 19.04 9.02 -1.660 0.546

05-22-00 180.6 40.00 8,035 5,770 19.97 10.65 -1.730 0.550 06-19-00 208.6 40.00 7,953 5,260 21.92 12.60 -1.700 0.625

07-24-00 *** 243.6 40.00 7,965 5,650 21.67 11.09 -1.713 0.633 10-23-00 334.6 40.00 8,000 5,470 20.80 11.78 -1.757 0.643 12-11-00 383.6 40.00 8,107 6,080 18.25 9.56 -1.764 0.640 02-07-01 441.6 40.00 8,076 6,330 19.02 8.73 -1.888 0.667 04-12-01 505.6 40.00 8,157 5,350 16.96 12.24 -1.878 0.794 06-14-01 568.6 40.00 8,161 5,150 16.84 13.05 -2.047 0.849 01-29-02 797.6 40.00 8,139 5,670 17.43 11.02 -2.235 0.992 06-21-02 940.6 40.00 7,997 5,050 20.83 13.47 -2.302 1.088 04-09-03 1,232.6 40.00 8,120 5,650 17.89 11.09 -2.668 1.375 04-01-05 1,955.6 40.00 8,050 5,630 19.59 11.17 NA NA



108

Test Pipe #2 (30-in dia. PVC pipe backfilled in crushed limestone; 101.0% relative compaction)

Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 45295 (G = 0.024627; K = - 0.02884)


Days

Cover

(ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-23-99 8:00 0.0 -2.67 9208 5520 0.00 11.58 0.000 0.000 11-23-99 10:40 0.1 -0.67 9179 6380 0.80 8.56 0.147 -0.284 11-23-99 12:30 0.2 0.0 9149 6210 1.52 9.12 0.187 -0.311 11-23-99 14:05 0.3 0.5 9114 6210 2.39 9.12 0.116 -0.265 11-23-99 15:50

* 0.3 1.0 9078 6100 3.26 9.49 0.071 -0.238

12-03-99 7:50 10.0 3.0 8918 5800 7.17 10.54 -0.158 -0.138 12-08-99 15:36 15.3 6.27 8720 6100 12.08 9.49 -0.295 -0.026 12-09-99 8:40 16.0 7.85 8629 6110 14.32 9.46 -0.301 -0.017

12-09-99 15:45 16.3 10.24 8618 6100 14.59 9.49 -0.317 0.038 12-16-99 8:40 23.0 11.96 8442 6160 18.93 9.29 NA NA

12-17-99 15:10 24.3 14.98 8381 6220 20.44 9.09 -0.558 0.089 12-20-99 17:48 27.4 16.77 8266 6180 23.27 9.22 -0.554 0.070 12-21-99 16:21 28.3 18.58 8123 6200 26.79 9.16 -0.592 0.081 12-22-99 8:00 29.0 20.14 7984 6170 30.21 9.26 -0.687 0.125

12-22-99 16:22 29.3 22.35 7928 6220 31.59 9.09 -0.713 0.117 12-23-99 8:47 30.0 23.11 7886 6080 32.62 9.56 -0.770 0.138 12-24-99 8:00 31.0 27.67 7704 5970 37.09 9.94 -1.078 0.306

12-27-99 16:05 34.3 32.34 7594 6280 39.83 8.89 -1.109 0.334 12-28-99 9:20 35.1 38.33 7377 6160 45.16 9.29 -1.361 0.407

12-29-99 10:42 **

36.1 40.00 7377 6430 45.18 8.40 NA NA

01-07-00 11:02 45.1 40.00 7380 6280 45.10 8.89 -1.682 0.564 04-12-00 12:00 141.2 40.00 7259 6100 48.06 9.49 -1.660 0.546

05-22-00 180.7 40.00 7244 5820 48.40 10.47 -1.730 0.550 07-24-00 *** 243.7 40.00 7222 5130 48.86 13.13 -1.700 0.625

07-31-00 252.7 40.00 -1.713 0.633 10-23-00 334.7 40.00 7170 5530 50.19 11.55 -1.757 0.643 12-11-00 383.7 40.00 7152 6020 50.69 9.77 -1.764 0.640 02-07-01 441.7 40.00 6972 6330 55.15 8.73 -1.888 0.667 04-12-01 505.7 40.00 7447 5790 43.40 10.58 -1.878 0.794 06-14-01 568.7 40.00 7710 5430 36.88 11.93 -2.047 0.849 01-29-02 797.7 40.00 6939 5870 55.92 10.29 -2.235 0.992 06-21-02 940.7 40.00 6852 5310 58.00 12.40 -2.302 1.088 04-09-03 1232.7 40.00 6873 5690 57.52 10.95 -2.668 1.375 04-28-04 1617.7 40.00 6793 5440 59.47 11.89 NA NA



109

Test Pipe #2 (30-in dia. PVC pipe backfilled in crushed limestone; 101.0% relative compaction

Vertical Soil Pressure Measured at Pipe Invert Pressure Cell: Serial # 45319 (G = 0.025472; K = - 0.02479)


Days

Cover

(ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-23-99 8:00 0.0 -2.67 8968 7860 0.00 4.31 0.000 0.000 11-23-99 10:40 0.1 -0.67 8953 5550 0.20 11.47 0.147 -0.284 11-23-99 12:30 0.2 0.0 8947 5550 0.36 11.47 0.187 -0.311 11-23-99 14:05 0.3 0.5 8935 5360 0.64 12.20 0.116 -0.265 11-23-99 15:50

* 0.3 1.0 8925 5440 0.91 11.89 0.071 -0.238

12-03-99 7:50 10.0 3.0 8871 5790 2.32 10.58 -0.158 -0.138 12-08-99 15:36 15.3 6.27 8723 5780 6.08 10.62 -0.295 -0.026 12-09-99 8:40 16.0 7.85 8704 5870 6.58 10.29 -0.301 -0.017

12-09-99 15:45 16.3 10.24 8689 5780 6.95 10.62 -0.317 0.038 12-16-99 8:40 23.0 11.96 8596 5980 9.34 9.91 NA NA

12-17-99 15:10 24.3 14.98 8528 5990 11.07 9.87 -0.558 0.089 12-20-99 17:48 27.4 16.77 8456 5780 12.89 10.62 -0.554 0.070 12-21-99 16:21 28.3 18.58 8344 5990 15.76 9.87 -0.592 0.081 12-22-99 8:00 29.0 20.14 8272 5950 17.59 10.01 -0.687 0.125

12-22-99 16:22 29.3 22.35 8214 6120 19.08 9.43 -0.713 0.117 12-23-99 8:47 30.0 23.11 8146 6080 20.81 9.56 -0.770 0.138 12-24-99 8:00 31.0 27.67 7992 5940 24.72 10.05 -1.078 0.306

12-27-99 16:05 34.3 32.34 7888 6140 27.38 9.36 -1.109 0.334 12-28-99 9:20 35.1 38.33 7724 6320 31.58 8.76 -1.361 0.407

12-29-99 10:42 **

36.1 40.00 7666 6430 33.06 8.40 NA NA

01-07-00 11:02 45.1 40.00 7669 6190 32.97 9.19 -1.682 0.564 04-12-00 12:00 141.2 40.00 7637 6030 33.77 9.73 -1.660 0.546

05-22-00 180.7 40.00 7622 5630 34.12 11.17 -1.730 0.550 07-24-00 *** 243.7 40.00 7583 5250 35.07 12.64 -1.700 0.625

07-31-00 252.7 40.00 -1.713 0.633 10-23-00 334.7 40.00 7682 5410 32.57 12.01 -1.757 0.643 12-11-00 383.7 40.00 7602 6090 34.67 9.53 -1.764 0.640 02-07-01 441.7 40.00 7433 6370 38.99 8.60 -1.888 0.667 04-12-01 505.7 40.00 7484 5500 37.62 11.66 -1.878 0.794 06-14-01 568.7 40.00 7335 5320 41.40 12.36 -2.047 0.849 01-29-02 797.7 40.00 7384 5770 40.19 10.65 -2.235 0.992 06-21-02 940.7 40.00 7300 5170 42.27 12.97 -2.302 1.088 04-09-03 1232.7 40.00 7234 5770 44.01 10.65 -2.668 1.375 04-28-04 1617.7 40.00 7239 5530 43.86 11.55 NA NA



110

Test Pipe #3 (30-in dia. PVC pipe backfilled in crushed rock; 86.2% relative compaction)

Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 49733 (G = 0.026242; K = 0.012324)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-22-99 7:23 0.00 -2.67 0.000 0.000 11-22-99 9:54 0.10 -0.67 9342 5880 0.00 10.26 0.152 -0.155

11-22-99 10:45 0.14 0.00 9329 4240 0.43 17.23 0.255 -0.236 11-22-99 14:12 * 0.28 1.00 9305 4780 1.02 14.64 0.157 -0.161 12-07-99 15:55 15.36 4.20 9155 6370 4.89 8.60 -0.974 0.730 12-09-99 9:06 17.07 6.75 9024 6590 8.32 7.89 -1.101 0.819

12-09-99 15:27 17.34 8.58 9005 6770 8.81 7.34 -1.133 0.829 12-16-99 16:30 24.38 10.33 8973 6550 9.66 8.02 -1.240 0.861 12-20-99 7:41 28.01 15.69 8958 6500 10.05 8.18 -1.436 0.998

12-21-99 16:59 ** 29.40 19.35 8897 6600 11.65 7.86 -1.544 1.050 12-29-99 12:38 37.22 19.35 8859 6670 12.64 7.65 -1.641 1.179 12-31-99 10:59 39.15 19.35 -1.653 1.226 01-04-00 14:42 43.31 19.35 -1.669 1.249 01-07-00 10:25 46.13 19.35 8842 6480 13.10 8.24 -1.690 1.240 02-21-00 16:15 91.37 19.35 -1.786 1.325 03-14-00 11:50 113.19 19.35 -1.880 1.396 04-10-00 14:52 140.31 19.35 8803 6250 14.13 8.99 -2.079 1.593 05-14-00 16:12 174.37 19.35 -2.128 1.635 05-22-00 12:50 182.23 19.35 8753 5640 15.47 11.13 -2.140 1.631 06-28-00 12:50 219.23 19.35 8693 5090 17.07 13.30 -2.124 1.827

07-07-00 8:00 *** 228.03 19.35 -2.065 1.763 08-01-00 17:02 253.40 19.35 8658 4920 18.00 14.02 -2.085 1.777 09-20-00 9:52 303.10 19.35 -2.100 1.836 10-23-00 9:55 335.11 19.35 8670 4810 17.69 14.51 -2.105 1.853

12-11-00 13:15 385.25 19.35 8747 5410 15.64 12.01 -2.050 1.923 12-14-00 387.69 19.35 8767 5500 15.11 11.66 NA NA 02-05-01 440.69 19.35 8690 5790 17.11 10.58 -2.132 1.949 03-12-01 475.69 19.35 8639 5860 18.45 10.33 -2.176 1.981 04-16-01 510.69 19.35 8589 5260 19.79 12.60 -2.210 1.992 06-14-01 569.69 19.35 8523 4790 21.55 14.60 -2.240 2.101 01-28-02 797.69 19.35 8684 5470 17.29 11.78 NA 2.067 06-21-02 941.69 19.35 8547 5020 20.90 13.59 NA NA 04-09-03 1233.69 19.35 8710 5910 16.58 10.15 NA NA 06-24-03 1309.69 19.35 8518 4960 21.67 13.85 NA NA 04-28-04 1618.69 19.35 8640 5620 18.43 11.21 -2.288 2.123 04-01-05 1956.69 19.35 8701 5460 16.84 11.81 NA NA



111


Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 49737 (G = 0.022188; K = 0.001308)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-22-99 7:23 0.00 -2.67 0.000 0.000 11-22-99 9:54 0.10 -0.67 8631 5780 0.22 10.62 0.152 -0.155

11-22-99 10:45 0.14 0.00 8615 5960 0.58 9.98 0.255 -0.236 11-22-99 14:12 * 0.28 1.00 8587 5660 1.20 11.06 0.157 -0.161 12-07-99 15:55 15.36 4.20 8498 5920 3.17 10.12 -0.974 0.730 12-09-99 9:06 17.07 6.75 8387 6020 5.64 9.77 -1.101 0.819

12-09-99 15:27 17.34 8.58 8360 6000 6.23 9.84 -1.133 0.829 12-16-99 16:30 24.38 10.33 8300 5910 7.57 10.15 -1.240 0.861 12-20-99 7:41 28.01 15.69 8215 6140 9.45 9.36 -1.436 0.998

12-21-99 16:59 ** 29.40 19.35 8094 6150 12.14 9.32 -1.544 1.050 12-29-99 12:38 37.22 19.35 8033 6350 13.49 8.66 -1.641 1.179 12-31-99 10:59 39.15 19.35 -1.653 1.226 01-04-00 14:42 43.31 19.35 -1.669 1.249 01-07-00 10:25 46.13 19.35 7998 6150 14.27 9.32 -1.690 1.240 02-21-00 16:15 91.37 19.35 -1.786 1.325 03-14-00 11:50 113.19 19.35 -1.880 1.396 04-10-00 14:52 140.31 19.35 7856 6030 17.42 9.73 -2.079 1.593 05-14-00 16:12 174.37 19.35 -2.128 1.635 05-22-00 12:50 182.23 19.35 7781 5460 19.08 11.81 -2.140 1.631 06-28-00 12:50 219.23 19.35 7711 4950 20.64 13.89 -2.124 1.827

07-07-00 8:00 *** 228.03 19.35 -2.065 1.763 08-01-00 17:02 253.40 19.35 7660 4820 21.77 14.46 -2.085 1.777 09-20-00 9:52 303.10 19.35 -2.100 1.836 10-23-00 9:55 335.11 19.35 7657 4890 21.84 14.15 -2.105 1.853

12-11-00 13:15 385.25 19.35 7730 5510 20.22 11.62 -2.050 1.923 12-14-00 387.69 19.35 7758 5610 19.59 11.24 NA NA 02-05-01 440.69 19.35 7618 5840 22.70 10.40 -2.132 1.949 03-12-01 475.69 19.35 7558 5770 24.03 10.65 -2.176 1.981 04-16-01 510.69 19.35 7530 5190 24.65 12.89 -2.210 1.992 06-14-01 569.69 19.35 7450 4750 26.43 14.78 -2.240 2.101 01-28-02 797.69 19.35 7601 5250 23.08 12.64 NA 2.067 06-21-02 941.69 19.35 7465 4970 26.10 13.81 NA NA 04-09-03 1233.69 19.35 7602 5870 23.05 10.29 NA NA 06-24-03 1309.69 19.35 7400 4950 27.54 13.89 NA NA 04-28-04 1618.69 19.35 7525 5420 24.76 11.97 -2.288 2.123 04-01-05 1956.69 19.35 7594 5580 23.23 11.36 NA NA



112

Test Pipe #4 (30-in dia. PVC pipe backfilled in sand; 87.8% relative compaction) Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 49729 (G = 0.023257; K = 0.017881)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-16-99 13:20 0.0 -0.67 8027 4520 0.00 15.85 0.307 -0.241 11-16-99 14:40 0.1 0.00 8016 5070 0.21 13.38 0.327 -0.255 11-16-99 15:05 0.1 0.50 0.237 -0.189 11-16-99 15:50 0.1 0.50 8001 5810 0.51 10.51 0.159 -0.146 11-16-99 16:20

* 0.1 1.00 7967 6500 1.26 8.18 0.096 -0.117

12-07-99 17:25 21.2 4.50 7815 6700 4.78 7.55 NA NA 12-08-99 15:50 22.1 6.88 7727 6870 6.82 7.04 -0.652 0.418 12-13-99 16:00 27.1 9.97 7690 6470 7.70 8.27 NA NA 12-16-99 16:00 30.1 12.12 7666 6840 8.24 7.13 NA NA 12-20-99 8:25 33.8 13.57 7635 6530 8.98 8.08 -0.961 0.534

12-21-99 15:11 35.1 16.54 7617 6780 9.38 7.31 -0.995 0.542 12-22-99 16:24 36.1 20.29 7560 6880 10.70 7.01 -1.170 0.633 12-29-99 10:48

** 42.9 20.29 7527 7400 11.44 5.53 -1.342 0.735

01-07-00 11:01 51.9 20.29 7507 6980 11.93 6.72 -1.355 0.715 04-14-00 12:00 149.9 20.29 7452 6490 13.24 8.21 -1.415 0.692

05-22-00 187.4 20.29 7408 5790 14.30 10.58 -1.431 0.802 06-22-00 218.4 20.29 7333 5040 16.10 13.51 -1.424 0.803

07-24-00 *** 250.4 20.29 7374 5280 15.13 12.52 -1.395 0.413 10-23-00 341.4 20.29 7420 4980 14.08 13.77 NA NA 12-11-00 390.4 20.29 7493 5780 12.33 10.62 NA NA 02-07-01 448.4 20.29 7543 6550 11.12 8.02 -1.419 0.457 02-20-01 461.4 20.29 7589 6320 10.06 8.76 -1.403 0.522 04-12-01 512.4 20.29 7614 5710 9.52 10.87 -1.493 0.816 06-14-01 575.4 20.29 7541 5300 11.24 12.44 NA NA 01-29-02 804.4 20.29 7485 5500 12.53 11.66 NA NA



113

Test Pipe #4 (30-in dia. HDPE pipe backfilled in sand; 87.8% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 49738 (G = 0.023566; K = 0.006193)

Cell Readings Pipe Deflection (%) +

Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)

Temp.

(°C)

Vertical Horizon.

11-16-99 13:20 0.0 -0.67 8809 7130 0.34 6.28 0.307 -0.241 11-16-99 14:40 0.1 0.00 8798 6880 0.60 7.01 0.327 -0.255 11-16-99 15:05 0.1 0.50 0.237 -0.189 11-16-99 15:50 0.1 0.50 8782 6940 0.98 6.83 0.159 -0.146 11-16-99 16:20

* 0.1 1.00 8775 6880 1.14 7.01 0.096 -0.117

12-07-99 17:25 21.2 4.50 8710 6390 2.68 8.53 NA NA 12-08-99 15:50 22.1 6.88 8668 6530 3.67 8.08 -0.652 0.418 12-13-99 16:00 27.1 9.97 8617 6290 4.88 8.86 NA NA 12-16-99 16:00 30.1 12.12 8580 6550 5.74 8.02 NA NA 12-20-99 8:25 33.8 13.57 8547 6290 6.53 8.86 -0.961 0.534

12-21-99 15:11 35.1 16.54 8519 6580 7.18 7.93 -0.995 0.542 12-22-99 16:24

** 36.1 20.29 8448 6730 8.85 7.46 -1.170 0.633

12-29-99 10:48 42.9 20.29 8426 7300 9.36 5.80 -1.342 0.735 01-07-00 11:01 51.9 20.29 8422 6860 9.46 7.07 -1.355 0.715 04-14-00 12:00 149.9 20.29 8368 6440 10.74 8.37 -1.415 0.692

05-22-00 187.4 20.29 8343 5750 11.35 10.73 -1.431 0.802 06-22-00 218.4 20.29 8291 4980 12.59 13.77 -1.424 0.803

07-24-00 *** 250.4 20.29 8303 5120 12.30 13.17 -1.395 0.413 10-23-00 341.4 20.29 8295 5060 12.49 13.43 NA NA 12-11-00 390.4 20.29 8346 5960 11.27 9.98 NA NA 02-07-01 448.4 20.29 8408 6640 9.80 7.74 -1.419 0.457 02-20-01 461.4 20.29 8480 6380 8.10 8.56 -1.403 0.522 04-12-01 512.4 20.29 8537 5380 6.78 12.13 -1.493 0.816 06-14-01 575.4 20.29 8485 5320 8.01 12.36 NA NA 01-29-02 804.4 20.29 8411 5730 9.74 10.80 NA NA



114




Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-16-99 10:15 0.0 -0.67 8556 4640 0.00 15.28 0.201 -0.106 11-16-99 14:40 0.2 0.00 8552 5440 0.16 11.89 0.266 -0.185 11-16-99 15:50 0.2 0.50 8542 6160 0.45 9.29 0.250 -0.156 11-17-99 8:55 * 0.9 1.00 8515 9680 1.26 0.17 0.189 -0.138 12-09-99 8:55 22.9 8.19 8255 6940 7.17 6.83 0.007 0.058

12-09-99 16:06 23.2 9.00 8240 6910 7.52 6.92 NA NA 12-13-99 16:00 27.2 10.11 8205 6700 8.32 7.55 NA NA 12-16-99 8:45 29.9 12.01 8194 6880 8.59 7.01 NA NA 12-17-99 8:20 30.9 14.94 8137 6870 9.91 7.04 -0.104 0.044

12-20-99 17:16 34.3 16.50 8096 6640 10.85 7.74 -0.129 0.117 12-21-99 16:12 35.2 18.28 8045 6730 12.04 7.46 -0.153 0.116 12-22-99 9:00 35.9 20.36 7997 6670 13.16 7.65 -0.190 0.157

12-22-99 16:25 36.3 22.66 7948 6810 14.30 7.22 -0.278 0.217 12-24-99 8:10 37.9 28.00 7780 6370 18.18 8.60 -0.487 0.377 12-27-99 10:31 41.0 29.15 7751 7070 18.90 6.45 -0.614 0.461 12-27-99 16:24 41.3 32.40 7728 6910 19.43 6.92 -0.632 0.486 12-28-99 9:06 42.0 38.47 7583 6950 22.80 6.80 -0.944 0.650

12-29-99 10:48 ** 43.0 40.00 7546 7080 23.67 6.42 -1.062 0.722 01-07-00 11:05 52.0 40.00 7511 6770 24.47 7.34 -1.163 0.811 04-14-00 12:00 150.1 40.00 7467 6370 25.46 8.60 -1.332 1.019

05-22-00 187.1 40.00 7451 5880 25.80 10.26 -1.396 1.013 06-22-00 218.6 40.00 7378 5240 27.45 12.68 -1.408 1.051

07-24-00 *** 250.6 40.00 7396 5270 27.04 12.56 -1.355 1.103 10-23-00 341.6 40.00 7423 5440 26.42 11.89 -1.403 1.153 12-14-00 393.6 40.00 7525 6250 24.11 8.99 -1.428 1.184 02-07-01 448.6 40.00 7631 6490 21.66 8.21 -1.595 1.297 02-20-01 461.6 40.00 7605 6300 22.25 8.82 -1.633 1.349 04-12-01 512.6 40.00 7429 5360 26.28 12.20 -2.237 2.012 06-14-01 575.6 40.00 7399 5150 26.96 13.05 -2.375 2.064 01-29-02 804.6 40.00 7560 6200 23.29 9.16 -2.452 2.198 06-21-02 947.6 40.00 7395 4990 27.04 13.72 -2.415 2.291 04-09-03 1239.6 40.00 7547 5850 23.57 10.37 -2.575 2.173 06-24-03 1315.6 40.00 7430 5050 26.23 13.47 -2.600 2.069 04-28-04 1624.6 40.00 7522 5620 24.13 11.21 -2.289 2.080 04-01-05 1962.6 40.00 7557 5780 23.33 10.62 NA NA



115




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)

Temp. (°C) Vertical Horizon.

11-16-99 10:15 0.0 -0.67 8838 6970 0.36 6.74 0.201 -0.106 11-16-99 14:40 0.2 0.00 8835 6870 0.43 7.04 0.266 -0.185 11-16-99 15:50 0.2 0.50 8826 6760 0.65 7.37 0.250 -0.156 11-17-99 8:55 * 0.9 1.00 8805 6930 1.17 6.86 0.189 -0.138 12-09-99 8:55 22.9 8.19 8639 6470 5.21 8.27 0.007 0.058

12-09-99 16:06 23.2 9.00 8632 6360 5.38 8.63 NA NA 12-13-99 16:00 27.2 10.11 8597 6190 6.23 9.19 NA NA 12-16-99 8:45 29.9 12.01 8573 6510 6.83 8.15 NA NA 12-17-99 8:20 30.9 14.94 8527 6450 7.95 8.34 -0.104 0.044

12-20-99 17:16 34.3 16.50 8488 6250 8.90 8.99 -0.129 0.117 12-21-99 16:12 35.2 18.28 8441 6400 10.06 8.50 -0.153 0.116 12-22-99 9:00 35.9 20.36 8383 6350 11.48 8.66 -0.190 0.157

12-22-99 16:25 36.3 22.66 8348 6490 12.34 8.21 -0.278 0.217 12-24-99 8:10 37.9 28.00 8210 6320 15.71 8.76 -0.487 0.377 12-27-99 10:31 41.0 29.15 8179 6800 16.49 7.25 -0.614 0.461 12-27-99 16:24 41.3 32.40 8140 6570 17.44 7.96 -0.632 0.486 12-28-99 9:06 42.0 38.47 7992 6520 21.06 8.11 -0.944 0.650

12-29-99 10:48 ** 43.0 40.00 7941 6800 22.32 7.25 -1.062 0.722 01-07-00 11:05 52.0 40.00 7917 6520 22.89 8.11 -1.163 0.811 04-14-00 12:00 150.1 40.00 7836 6170 24.86 9.26 -1.332 1.019

05-22-00 187.1 40.00 7832 5740 24.94 10.76 -1.396 1.013 06-22-00 218.6 40.00 7784 5160 26.08 13.01 -1.408 1.051

07-24-00 *** 250.6 40.00 7783 5240 26.11 12.68 -1.355 1.103 10-23-00 341.6 40.00 7779 5380 26.22 12.13 -1.403 1.153 12-14-00 393.6 40.00 7868 6280 24.08 8.89 -1.428 1.184 02-07-01 448.6 40.00 7814 6480 25.41 8.24 -1.595 1.297 02-20-01 461.6 40.00 -1.633 1.349 04-12-01 512.6 40.00 7623 5270 30.03 12.56 -2.237 2.012 06-14-01 575.6 40.00 7555 5250 31.70 12.64 -2.375 2.064 01-29-02 804.6 40.00 7716 6170 27.80 9.26 -2.452 2.198 06-21-02 947.6 40.00 -2415 2.291 04-09-03 1239.6 40.00 -2.575 2.173 06-24-03 1315.6 40.00 -2.600 2.069 04-28-04 1624.6 40.00 -2.289 2.080

[Notes] “NA” = Data Not Available * End of Initial Backfilling ** End of Construction *** End of Initial Monitoring Phase


116


Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 49731 (G = 0.021860; K = 0.001201)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-15-99 11:30 0.0 -0.67 9353 5280 0.00 12.52 0.137 -0.063 11-15-99 13:30 0.1 0.00 9341 5500 0.26 11.66 0.260 -0.161 11-15-99 14:45 0.1 0.50 9331 5470 0.48 11.78 0.318 -0.144 11-15-99 16:00

* 0.2 1.00 9314 5450 0.85 11.85 0.313 -0.171

12-09-99 9:35 23.9 7.01 9028 6790 7.10 7.28 -0.158 0.643 12-09-99 17:17 24.2 9.12 8996 6710 7.80 7.52 -0.183 0.660 12-15-99 16:25 30.2 10.67 8969 6540 8.39 8.05 -0.223 0.667 12-21-99 17:06

** 36.2 19.35 8964 6680 8.50 7.62 -0.483 0.810

12-29-99 12:38 44.0 19.35 8939 6760 9.04 7.37 -0.603 0.894 01-07-00 10:20 53.0 19.35 8907 6510 9.74 8.15 -0.615 0.906

04-12-00 148.5 19.35 8942 6240 8.98 9.02 -0.757 1.067 05-22-00 188.5 19.35 8876 5580 10.43 11.36 -0.794 1.083 06-19-00 216.5 19.35 8783 4970 12.46 13.81 NA NA

07-24-00 *** 251.5 19.35 8741 4790 13.38 14.60 -0.691 1.184 10-23-00 342.5 19.35 8760 4770 12.97 14.69 -0.672 1.192 12-11-00 391.5 19.35 8872 5400 10.51 12.05 -0.731 1.166 12-14-00 394.5 19.35 8903 5600 9.84 11.28 NA NA 02-07-01 449.5 19.35 8851 5910 10.97 10.15 -0.781 1.130 03-12-01 482.5 19.35 8793 5810 12.24 10.51 -0.797 1.069 04-12-01 513.5 19.35 8711 5260 14.03 12.60 -0.822 1.056 06-14-01 576.5 19.35 8608 4720 16.29 14.91 -0.823 1.580 01-29-02 805.5 19.35 8805 5460 11.98 11.81 -0.874 1.588 06-21-02 948.5 19.35 8669 4890 14.95 14.15 NA NA 04-09-03 1240.5 19.35 8866 5930 10.64 10.08 -1.040 1.634 06-24-03 1316.5 19.35 8638 4950 15.63 13.89 NA NA 04-28-04 1625.5 19.35 8778 5690 12.57 10.95 NA NA 04-01-05 1963.5 19.35 8844 5700 11.12 10.91 NA NA



117

Test Pipe #6 (30-in dia. PVC pipe backfilled in crushed rock; 97.0% relative

compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 50405 (G = 0.018102; K = - 0.00122)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-15-99 11:30 0.0 -0.67 8988 5800 0.46 10.54 0.137 -0.063 11-15-99 13:30 0.1 0.00 8978 5730 0.64 10.80 0.260 -0.161 11-15-99 14:45 0.1 0.50 8977 5750 0.66 10.73 0.318 -0.144 11-15-99 16:00

* 0.2 1.00 8963 5740 0.91 10.76 0.313 -0.171

12-09-99 9:35 23.9 7.01 8802 6340 3.83 8.69 -0.158 0.643 12-09-99 17:17 24.2 9.12 8778 6260 4.26 8.96 -0.183 0.660 12-15-99 16:25 30.2 10.67 8727 6260 5.18 8.96 -0.223 0.667 12-21-99 17:06

** 36.2 19.35 8535 6420 8.66 8.43 -0.483 0.810

12-29-99 12:38 44.0 19.35 8499 6560 9.31 7.99 -0.603 0.894 01-07-00 10:20 53.0 19.35 8474 6340 9.76 8.69 -0.615 0.906

04-12-00 148.5 19.35 8451 6150 10.18 9.32 -0.757 1.067 05-22-00 188.5 19.35 8410 5550 10.92 11.47 -0.794 1.083 06-19-00 216.5 19.35 8339 5010 12.20 13.64 NA NA

07-24-00 *** 251.5 19.35 8304 4860 12.83 14.29 -0.691 1.184 10-23-00 342.5 19.35 8316 4890 12.62 14.15 -0.672 1.192 12-11-00 391.5 19.35 8411 5530 10.90 11.55 -0.731 1.166 12-14-00 394.5 19.35 8446 5820 10.27 10.47 NA NA 02-07-01 449.5 19.35 8380 5970 11.46 9.94 -0.781 1.130 03-12-01 482.5 19.35 8330 5900 12.37 10.19 -0.797 1.069 04-12-01 513.5 19.35 8312 5270 12.69 12.56 -0.822 1.056 06-14-01 576.5 19.35 8216 4870 14.43 14.24 -0.823 1.580 01-29-02 805.5 19.35 8360 5480 11.82 11.74 -0.874 1.588 06-21-02 948.5 19.35 8257 4980 13.69 13.77 NA NA 04-09-03 1240.5 19.35 8426 5880 10.63 10.26 -1.040 1.634 06-24-03 1316.5 19.35 8230 4990 14.17 13.72 NA NA 04-28-04 1625.5 19.35 8327 5790 12.42 10.58 NA NA 04-01-05 1963.5 19.35 8393 5790 11.23 10.58 NA NA



118

Test Pipe #7 (30-in dia. HDPE pipe backfilled in sand; 95.6% relative compaction) Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 49732 (G = 0.022613; K = 0.003598)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-10-99 14:30 0.0 -0.67 8938 5200 0.00 12.85 0.297 -0.693 11-10-99 16:30 0.1 0.00 8928 5330 0.22 12.32 0.420 -0.881 11-11-99 9:30 0.8 0.50 8901 5720 0.83 10.84 0.393 -0.987

11-11-99 12:00 *

0.9 1.00 8880 5540 1.31 11.51 0.404 -0.994

12-02-99 8:45 21.8 3.00 8845 6770 2.08 7.34 0.268 -0.946 12-08-99 7:15 27.7 5.53 8733 6630 4.62 7.77 0.153 -0.930 12-09-99 9:05 28.8 7.26 8657 6840 6.33 7.13 0.116 -0.917

12-09-99 16:29 29.1 9.86 8643 6720 6.65 7.49 0.097 -0.899 12-16-99 16:03 36.1 11.95 8650 6790 6.49 7.28 NA NA 12-20-99 8:30 39.8 13.34 8638 6320 6.77 8.76 NA NA

12-21-99 15:16 41.0 16.47 8623 6700 7.10 7.55 -0.102 -0.898 12-22-99 16:32

** 42.1 20.33 8587 6800 7.92 7.25 NA NA

12-29-99 11:16 48.9 20.33 8592 7250 7.80 5.94 -0.375 -0.903 01-07-00 57.9 20.33 8595 6860 7.74 7.07 -0.370 -0.901 04-12-00 153.9 20.33 8602 6390 7.58 8.53 -0.397 -0.801 05-22-00 193.4 20.33 8614 5830 7.32 10.44 -0.516 -0.817 06-22-00 224.4 20.33 8585 4990 7.99 13.72 -0.413 -0.816

07-24-00 *** 256.4 20.33 8617 5130 7.26 13.13 -0.428 -0.824 10-23-00 347.4 20.33 8627 4950 7.04 13.89 -0.367 -0.839 12-14-00 399.4 20.33 8679 5800 5.85 10.54 -0.399 -0.867 02-07-01 454.4 20.33 8678 6340 5.86 8.69 -0.407 -0.867 04-12-01 518.4 20.33 8587 5210 7.94 12.80 -0.349 -0.850 06-14-01 581.4 20.33 8576 5240 8.19 12.68 NA NA 01-29-02 810.4 20.33 8600 5610 7.64 11.24 -0.556 NA 06-21-02 953.4 20.33 8574 5110 8.23 13.22 -0.485 NA 04-09-03 1245.4 20.33 8635 5960 6.84 9.98 NA NA 04-28-04 1630.4 20.33 8620 5890 7.18 10.22 -0.727 -0.865 04-01-05 1968.4 20.33 8629 5890 6.98 10.22 NA NA



119

Test Pipe #7 (30-in dia. HDPE pipe backfilled in sand; 95.6% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 49735 (G = 0.027276; K = 0.00735)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-10-99 14:30 0.0 -0.67 9063 4980 0.44 13.77 0.297 -0.693 11-10-99 16:30 0.1 0.00 9068 4730 0.31 14.87 0.420 -0.881 11-11-99 9:30 0.8 0.50 9057 5110 0.60 13.22 0.393 -0.987

11-11-99 12:00 *

0.9 1.00 9053 5130 0.70 13.13 0.404 -0.994

12-02-99 8:45 21.8 3.00 9047 6400 0.83 8.50 0.268 -0.946 12-08-99 7:15 27.7 5.53 9010 6500 1.84 8.18 0.153 -0.930 12-09-99 9:05 28.8 7.26 8982 6460 2.60 8.31 0.116 -0.917

12-09-99 16:29 29.1 9.86 8962 6290 3.15 8.86 0.097 -0.899 12-16-99 16:03 36.1 11.95 8952 6450 3.42 8.34 NA NA 12-20-99 8:30 39.8 13.34 8937 6100 3.84 9.49 NA NA

12-21-99 15:16 41.0 16.47 8901 6440 4.81 8.37 -0.102 -0.898 12-22-99 16:32

** 42.1 20.33 8844 6570 6.37 7.96 NA NA

12-29-99 11:16 48.9 20.33 8837 7100 6.55 6.37 -0.375 -0.903 01-07-00 57.9 20.33 8846 6720 6.31 7.49 -0.370 -0.901 04-12-00 153.9 20.33 8839 6260 6.51 8.96 -0.397 -0.801 05-22-00 193.4 20.33 8813 5790 7.23 10.58 -0.516 -0.817 06-22-00 224.4 20.33 8787 5060 7.96 13.43 -0.413 -0.816

07-24-00 *** 256.4 20.33 8825 5180 6.92 12.93 -0.428 -0.824 10-23-00 347.4 20.33 8885 5040 5.29 13.51 -0.367 -0.839 12-14-00 399.4 20.33 8934 6070 3.92 9.60 -0.399 -0.867 02-07-01 454.4 20.33 8923 6600 4.21 7.86 -0.407 -0.867 04-12-01 518.4 20.33 8924 5360 4.22 12.20 -0.349 -0.850 06-14-01 581.4 20.33 8893 5370 5.06 12.16 NA NA 01-29-02 810.4 20.33 8886 5710 5.24 10.87 -0.556 NA 06-21-02 953.4 20.33 8871 5180 5.67 12.93 -0.485 NA 04-09-03 1245.4 20.33 8889 6000 5.15 9.84 NA NA 04-28-04 1630.4 20.33 8868 6001 5.73 9.83 -0.727 -0.865 04-01-05 1968.4 20.33 8859 5960 5.97 9.98 NA NA



120

Test Pipe #8 (30-in dia. HDPE pipe backfilled in sand; 95.6% relative compaction) Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 45318 (G = 0.024652; K = - 0.02399)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-10-99 8:30 0.0 -0.67 8945 5710 0.00 10.87 0.453 -0.668 11-10-99 16:30 0.3 0.00 8940 5550 0.11 11.47 0.471 -0.679 11-11-99 9:30 1.0 0.50 8922 5740 0.57 10.76 0.372 -0.684

11-11-99 12:00 *

1.1 1.00 8894 5460 1.23 11.81 0.356 -0.684

12-02-99 9:05 22.0 3.00 8854 6530 2.31 8.08 0.061 -0.513 12-08-99 15:58 28.3 6.13 8733 6540 5.29 8.05 -0.216 -0.443 12-09-99 9:05 29.0 7.76 8718 6630 5.67 7.77 -0.292 -0.440

12-09-99 16:31 29.3 9.54 8714 6530 5.76 8.08 -0.315 -0.432 12-16-99 8:49 36.0 11.89 8698 6640 6.16 7.74 NA NA

12-17-99 15:30 37.3 15.22 8669 6490 6.87 8.21 -0.750 -0.387 12-20-99 16:58 40.4 16.00 8656 6390 7.18 8.53 NA NA 12-21-99 9:25 41.0 16.89 8646 6470 7.43 8.27 -0.820 -0.310

12-21-99 16:02 41.3 18.10 8627 6500 7.90 8.18 -0.873 -0.299 12-22-99 10:40 42.1 20.51 8598 6450 8.62 8.34 -0.975 -0.269 12-22-99 16:45 42.3 22.79 8584 6540 8.97 8.05 -1.120 -0.218 12-24-99 8:20 44.0 28.15 8508 6280 10.82 8.89 -1.435 -0.150

12-27-99 10:44 47.1 29.63 8503 6810 10.98 7.22 -1.631 -0.126 12-27-99 16:48 47.3 32.39 8471 6530 11.75 8.08 -1.678 -0.112 12-28-99 8:56 48.0 39.04 8391 6560 13.73 7.99 -2.096 -0.032

12-29-99 11:17 **

49.1 40.00 8376 6870 14.12 7.04 -2.175 -0.089

01-07-00 11:05 58.1 40.00 8394 6610 13.66 7.83 -2.367 -0.083 05-22-00 193.6 40.00 8379 5880 13.97 10.26 -2.823 0.019 06-22-00 224.6 40.00 8352 5200 14.57 12.85 -2.862 0.023

07-24-00 *** 256.6 40.00 8359 5210 14.40 12.80 -2.819 0.069 10-23-00 347.6 40.00 8369 5380 14.17 12.13 -2.883 0.044 12-14-00 399.6 40.00 8414 6210 13.13 9.12 -2.932 0.031 02-07-01 454.6 40.00 8362 6320 14.42 8.76 -2.981 0.006 04-12-01 518.6 40.00 8273 5320 16.53 12.36 -2.779 -0.093 06-14-01 581.6 40.00 8285 5190 16.22 12.89 -2.805 -0.139 01-29-02 810.6 40.00 8337 5630 14.98 11.17 NA NA 06-21-02 953.6 40.00 8300 4970 15.83 13.81 NA NA 04-09-03 1245.6 40.00 8375 5770 14.06 10.65 -2.807 -0.166 04-28-04 1630.6 40.00 8371 5580 14.14 11.36 -2.879 -0.196 04-01-05 1968.6 40.00 8382 5640 13.87 11.13 NA NA



121

Test Pipe #8 (30-in dia. HDPE pipe backfilled in sand; 95.6% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 45310 (G = 0.02301; K = - 0.02463)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-10-99 8:30 0.0 -0.67 8859 4830 0.91 14.42 0.453 -0.668 11-10-99 16:30 0.3 0.00 8862 4660 0.83 15.19 0.471 -0.679 11-11-99 9:30 1.0 0.50 8849 5130 1.18 13.13 0.372 -0.684

11-11-99 12:00 *

1.1 1.00 8840 5110 1.38 13.22 0.356 -0.684

12-02-99 9:05 22.0 3.00 8835 6100 1.59 9.49 0.061 -0.513 12-08-99 15:58 28.3 6.13 8753 6170 3.48 9.26 -0.216 -0.443 12-09-99 9:05 29.0 7.76 8732 6250 3.97 8.99 -0.292 -0.440

12-09-99 16:31 29.3 9.54 8721 6200 4.22 9.16 -0.315 -0.432 12-16-99 8:49 36.0 11.89 8658 6300 5.68 8.82 NA NA

12-17-99 15:30 37.3 15.22 8608 6260 6.82 8.96 -0.750 -0.387 12-20-99 16:58 40.4 16.00 8580 6150 7.46 9.32 NA NA 12-21-99 9:25 41.0 16.89 8562 6240 7.88 9.02 -0.820 -0.310

12-21-99 16:02 41.3 18.10 8540 6250 8.39 8.99 -0.873 -0.299 12-22-99 10:40 42.1 20.51 8491 6250 9.52 8.99 -0.975 -0.269 12-22-99 16:45 42.3 22.79 8468 6320 10.05 8.76 -1.120 -0.218 12-24-99 8:20 44.0 28.15 8370 6120 12.29 9.43 -1.435 -0.150

12-27-99 10:44 47.1 29.63 8360 6600 12.56 7.86 -1.631 -0.126 12-27-99 16:48 47.3 32.39 8319 6140 13.46 9.36 -1.678 -0.112 12-28-99 8:56 48.0 39.04 8217 6560 15.85 7.99 -2.096 -0.032

12-29-99 11:17 **

49.1 40.00 8199 6650 16.27 7.71 -2.175 -0.089

01-07-00 11:05 58.1 40.00 8208 6420 16.04 8.43 -2.367 -0.083 05-22-00 193.6 40.00 8192 5790 16.36 10.58 -2.823 0.019 06-22-00 224.6 40.00 8165 5230 16.92 12.72 -2.862 0.023

07-24-00 *** 256.6 40.00 8168 5190 16.85 12.89 -2.819 0.069 10-23-00 347.6 40.00 8175 5360 16.71 12.20 -2.883 0.044 12-14-00 399.6 40.00 8222 6180 15.70 9.22 -2.932 0.031 02-07-01 454.6 40.00 8168 6440 16.96 8.37 -2.981 0.006 04-12-01 518.6 40.00 8227 5380 15.51 12.13 -2.779 -0.093 06-14-01 581.6 40.00 8224 5210 15.57 12.80 -2.805 -0.139 01-29-02 810.6 40.00 8236 5610 15.33 11.24 NA NA 06-21-02 953.6 40.00 8223 5040 15.57 13.51 NA NA 04-09-03 1245.6 40.00 8292 5690 14.05 10.95 -2.807 -0.166 04-28-04 1630.6 40.00 8310 5510 13.62 11.62 -2.879 -0.196 04-01-05 1968.6 40.00 8331 5770 13.16 10.65 NA NA



122

Test Pipe #8 (30-in dia. HDPE pipe backfilled in sand; 95.6% relative compaction) Vertical Soil Pressure Measured at Pipe Invert Pressure Cell: Serial # 45311 (G = 0.023598; K = - 0.01588)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-09-99 15:30 0.0 -2.67 8931 2840 0.00 26.20 0.453 -0.668 11-10-99 8:30 0.3 -2.00 8928 5650 0.31 11.09 0.471 -0.679 11-11-99 9:30 1.0 0.50 8914 5240 0.62 12.68 0.372 -0.684

11-11-99 12:00 *

1.1 1.00 8905 5220 0.83 12.76 0.356 -0.684

12-02-99 9:05 22.0 3.00 0.061 -0.513 12-08-99 15:58 28.3 6.13 8816 5760 2.96 10.69 -0.216 -0.443 12-09-99 9:05 29.0 7.76 8801 5860 3.32 10.33 -0.292 -0.440

12-09-99 16:31 29.3 9.54 8773 5650 3.97 11.09 -0.315 -0.432 12-16-99 8:49 36.0 11.89 8734 6000 4.91 9.84 NA NA

12-17-99 15:30 37.3 15.22 8700 5950 5.71 10.01 -0.750 -0.387 12-20-99 16:58 40.4 16.00 8672 5830 6.36 10.44 NA NA 12-21-99 9:25 41.0 16.89 8651 5860 6.86 10.33 -0.820 -0.310

12-21-99 16:02 41.3 18.10 8621 5940 7.57 10.05 -0.873 -0.299 12-22-99 10:40 42.1 20.51 8577 5900 8.61 10.19 -0.975 -0.269 12-22-99 16:45 42.3 22.79 8549 5940 9.27 10.05 -1.120 -0.218 12-24-99 8:20 44.0 28.15 8469 5890 11.16 10.22 -1.435 -0.150

12-27-99 10:44 47.1 29.63 -1.631 -0.126 12-27-99 16:48 47.3 32.39 8440 5860 11.84 10.33 -1.678 -0.112 12-28-99 8:56 48.0 39.04 8354 6280 13.89 8.89 -2.096 -0.032

12-29-99 11:17 **

49.1 40.00 8347 6220 14.05 9.09 -2.175 -0.089

01-07-00 11:05 58.1 40.00 8378 6180 13.32 9.22 -2.367 -0.083 05-22-00 193.6 40.00 8411 5750 12.52 10.73 -2.823 0.019 06-22-00 224.6 40.00 8390 5340 12.99 12.28 -2.862 0.023

07-24-00 *** 256.6 40.00 8396 5280 12.84 12.52 -2.819 0.069 10-23-00 347.6 40.00 8129 5380 19.15 12.13 -2.883 0.044 12-14-00 399.6 40.00 8451 6040 11.59 9.70 -2.932 0.031 02-07-01 454.6 40.00 8401 6400 12.79 8.50 -2.981 0.006 04-12-01 518.6 40.00 8419 5580 12.32 11.36 -2.779 -0.093 06-14-01 581.6 40.00 8405 5260 12.63 12.60 -2.805 -0.139 01-29-02 810.6 40.00 NA NA 06-21-02 953.6 40.00 8413 5240 12.44 12.68 NA NA 04-09-03 1245.6 40.00 -2.807 -0.166 04-28-04 1630.6 40.00 -2.879 -0.196 04-01-05 1968.6 40.00 8492 5890 10.61 10.22 NA NA



123

Test Pipe #9 (30-in dia. HDPE pipe backfilled in crushed limestone; 86.9% relative compaction)

Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 8-1301 (G = 0.023512; K = - 0.02749)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-09-99 10:45 0.0 - 0.67 9,167 2,860 0.00 26.04 0.342 0.043 11-09-99 11:30 0.0 0.0 9,148 3,130 0.50 23.98 0.392 0.039 11-09-99 13:30 0.1 0.5 9,153 4,240 0.57 17.23 0.359 0.029 11-09-99 14:30

* 0.2 1.0 9,129 4,310 1.15 16.88 0.309 0.348

12-02-99 14:50 23.2 3.0 9,102 6,970 2.06 6.74 -0.367 0.229 12-08-99 16:30 29.2 5.13 8,966 6,690 5.23 7.59 -1.002 0.725 12-09-99 9:40 30.0 7.23 8,930 6,740 6.08 7.43 -1.090 0.750

12-15-99 16:28 36.2 10.66 8,935 6,560 5.95 7.99 -1.219 0.800 12-16-99 16:45 37.3 12.94 8,932 6,610 6.03 7.83 -1.323 0.826 12-17-99 8:30 37.9 16.14 8,902 6,650 6.73 7.71 -1.465 0.872 12-21-99 9:00 41.9 18.00 8,884 6,520 7.15 8.11 -1.605 0.911

12-21-99 17:09 **

42.3 19.93 8,870 6,540 7.48 8.05 -1.677 0.931

12-29-99 12:52 50.1 19.93 8,855 6,670 7.84 7.65 -1.813 0.954 01-07-00 10:30 59.0 19.93 8,850 6,450 7.94 8.34 -2.087 1.031 04-12-00 12:00 155.1 19.93 8,844 6,210 8.06 9.12 -2.057 0.936

05-22-00 194.6 19.93 8,843 5,690 8.03 10.95 -2.079 0.914 06-19-00 222.6 19.93 8,809 5,000 8.76 13.68 -2.069 1.012

07-24-00 *** 257.6 19.93 8,801 4,770 8.92 14.69 -2.070 0.998 10-23-00 348.6 19.93 8,819 4,790 8.50 14.60 -2.073 1.026 12-11-00 397.6 19.93 8,879 5,370 7.15 12.16 -2.076 1.227 12-14-00 400.6 19.93 8,890 5,540 6.91 11.51 NA NA 02-07-01 455.6 19.93 8,879 5,770 7.19 10.65 -2.111 1.195 03-12-01 488.6 19.93 8,865 5,800 7.53 10.54 -2.129 1.194 04-12-01 519.6 19.93 8,815 5,240 8.64 12.68 -2.099 1.160 06-14-01 582.6 19.93 8,780 4,750 9.41 14.78 -2.049 1.170 01-29-02 811.6 19.93 8,865 5,280 7.47 12.52 -2.129 1.126 06-21-02 954.6 19.93 8,807 4,870 8.79 14.24 NA NA 04-09-03 1,246.6 19.93 8,911 5,910 6.46 10.15 -2.129 1.152 06-24-03 1,322.6 19.93 8,812 4,830 8.67 14.42 -2.118 1.143 04-28-04 1,631.6 19.93 8,871 5,750 7.38 10.73 -2.064 1.216

The cable was damaged, and the sensor went dead. [Notes] “NA” = Data Not Available. * End of Initial Backfilling ** End of Embankment Construction *** End of Initial Monitoring Phase


124

Test Pipe #9 (30-in dia. HDPE pipe backfilled in crushed limestone; 86.9% relative compaction)

Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 8-1277 (G = 0.023714; K = - 0.00644)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-09-99 09:00 0.0 - 2.0 8,286 4,760 0.00 14.73 NA NA 11-09-99 10:00 0.0 - 1.3 8,260 3,500 0.38 21.46 NA NA 11-09-99 10:45 0.1 - 0.67 8,272 5,280 0.35 12.52 0.342 0.043 11-09-99 11:30 0.1 0.0 8,270 5,420 0.40 11.97 0.392 0.039 11-09-99 13:30 0.2 0.5 8,267 5,410 0.47 12.01 0.359 0.029 11-09-99 14:30

* 0.2 1.0 8,254 5,370 0.78 12.16 0.309 0.348

12-02-99 14:50 23.2 3.0 8,229 6,230 1.39 9.06 -0.367 0.229 12-07-99 15:40 28.3 4.31 8,162 6,060 2.97 9.63 -0.802 0.545 12-08-99 16:30 29.3 5.13 8,155 6,180 3.14 9.22 -1.002 0.725 12-09-99 9:40 30.0 7.23 8,110 6,290 4.21 8.86 -1.090 0.750

12-09-99 17:22 30.3 9.0 8,102 6,230 4.40 9.06 NA NA 12-13-99 16:40 34.3 9.21 8,101 6,000 4.42 9.84 -1.140 0.771 12-15-06 16:28 36.3 10.66 8,054 6,140 5.54 9.36 -1.219 0.800 12-16-99 16:45 37.3 12.94 8,024 6,370 6.25 8.60 -1.323 0.826 12-17-99 8:30 38.0 16.14 7,972 6,410 7.49 8.47 -1.465 0.872 12-20-99 8:05 41.0 16.14 7,938 6,020 8.28 9.77 NA NA

12-21-99 17:09 **

42.3 19.93 7,897 6,290 9.26 8.86 -1.677 0.931

12-29-99 12:52 50.2 19.93 7,891 6,500 9.41 8.18 -1.813 0.954 01-07-00 10:30 59.1 19.93 7,885 6,280 9.55 8.89 -2.087 1.031 04-12-00 12:00 155.1 19.93 7,935 6,120 8.36 9.43 -2.057 0.936

05-22-00 194.6 19.93 7,932 5,630 8.42 11.17 -2.079 0.914 06-19-00 222.6 19.93 7,900 5,030 9.16 13.55 -2.069 1.012

07-24-00 *** 257.6 19.93 7,894 4,830 9.30 14.42 -2.070 0.998 10-23-00 348.6 19.93 7,904 4,930 9.06 13.98 -2.073 1.026 12-11-00 397.6 19.93 7,955 5,590 7.87 11.32 -2.076 1.227 12-14-00 400.6 19.93 7,969 5,820 7.54 10.47 NA NA 02-07-01 455.6 19.93 7,955 6,000 7.88 9.84 -2.111 1.195 03-12-01 488.6 19.93 7,940 5,890 8.23 10.22 -2.129 1.194 04-12-01 519.6 19.93 7,899 5,200 9.19 12.85 -2.099 1.160 06-14-01 582.6 19.93 7,874 4,810 9.77 14.51 -2.049 1.170 01-29-02 811.6 19.93 7,942 5,430 8.18 11.93 -2.129 1.126 06-21-02 954.6 19.93 7,901 4,950 9.14 13.89 NA NA 04-09-03 1,246.6 19.93 7,994 5,990 6.96 9.87 -2.129 1.152 06-24-03 1,322.6 19.93 7,912 4,930 8.87 13.98 -2.118 1.143 04-28-04 1,631.6 19.93 7,961 5,810 7.73 10.51 -2.064 1.216 04-01-05 1,969.6 19.93 7,975 5,890 7.40 10.22 NA NA



125

Test Pipe #10 (30-in dia. HDPE pipe backfilled in sand; 86.9% relative compaction) Vertical Soil Pressure Measured at Pipe Crown Pressure Cell: Serial # 8-1266 (G = 0.023712; K = - 0.01356)


Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-05-99 10:00 0.0 - 0.67 8,982 4,630 0.00 15.33 -0.067 -0.455 11-05-99 11:00 0.0 0.00 8,976 4,830 0.15 14.42 0.040 -0.501 11-05-99 13:30 0.1 0.50 8,955 5,270 0.68 12.56 0.036 -0.420 11-05-99 14:45

* 0.2 1.00 8,931 5,120 1.24 13.17 -0.017 -0.367

12-02-99 11:50 27.1 3.00 8,879 6,990 2.56 6.69 -1.526 0.964 12-07-99 17:50 32.3 4.50 8,853 6,590 3.16 7.89 -1.921 1.279 12-16-99 16:07 41.3 11.42 8,714 6,880 6.47 7.01 NA NA 12-20-99 8:35 44.9 13.38 8,704 6,520 6.69 8.11 -2.821 1.645 12-21-99 9:42 46.0 14.93 8,691 6,140 6.98 9.36 -3.008 1.778

12-21-99 15:21 46.2 16.23 8,663 6,770 7.67 7.34 -3.097 1.801 12-22-99 16:47

** 47.3 20.31 8,592 6,900 9.36 6.95 -3.510 1.980

12-29-99 11:31 54.1 20.31 8,598 7,270 9.23 5.89 -3.831 2.032 01-07-00 12:00 63.1 20.31 8,604 7,020 9.08 6.60 -3.873 2.038 04-12-00 12:00 161.1 20.31 8,609 6,500 8.94 8.18 -3.930 2.118

05-22-00 198.6 20.31 8,626 5,860 8.51 10.33 -3.971 2.120 06-19-00 226.6 20.31 8,615 5,200 8.74 12.85 -3.778 2.124

07-24-00 *** 261.6 20.31 8,634 5,160 8.28 13.01 -3.843 2.224 10-23-00 352.6 20.31 8,615 4,900 8.72 14.11 -4.170 2.331 12-14-00 404.6 20.31 8,657 5,960 7.78 9.98 -4.403 2.375 02-07-01 459.6 20.31 8,637 6,530 8.28 8.08 -4.653 2.463 04-12-01 523.6 20.31 8,522 5,170 10.94 12.97 NA NA 06-14-01 586.6 20.31 8,542 5,140 10.46 13.09 NA NA 01-29-02 815.6 20.31 8,590 5,560 9.35 11.43 NA NA 06-21-02 958.6 20.31 8,567 5,070 9.87 13.38 NA NA 04-03-03 1,242.6 20.31 8,637 6,090 8.26 9.53 NA NA 06-24-03 1,326.6 20.31 8,583 5,420 9.51 11.97 NA NA 04-28-04 1,635.6 20.31 8,614 5,940 8.80 10.05 -4.825 2.486 04-01-05 1,973.6 20.31 8,621 6,010 8.63 9.80 NA NA



126

Test Pipe #10 (30-in dia. HDPE pipe backfilled in sand; 86.9% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 8-1278 (G = 0.023684; K = - 0.01824)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-01-99 14:30 0.0 -2.00 9,216 6,740 0.0 7.43 0.007 0.015 11-05-99 8:45 3.8 - 1.33 9,208 6,310 0.16 8.79 -0.159 -0.398

11-05-99 11:00 0.0 0.00 9,201 7,420 0.39 5.47 -0.067 -0.455 11-05-99 13:30 0.1 0.50 9,195 7,030 0.51 6.57 0.036 -0.420 11-05-99 14:45

* 0.2 1.00 9,188 6,740 0.66 7.43 -0.017 -0.367

12-02-99 11:50 27.1 3.00 9,172 6,270 1.01 8.92 -1.526 0.964 12-07-99 17:50 32.3 4.50 9,168 6,100 1.10 9.49 -1.921 1.279 12-09-99 16:52 38.1 7.16 9,049 6,270 3.93 8.92 -2.365 1.596 12-16-99 16:07 41.3 11.42 9,001 6,380 5.07 8.56 NA NA 12-20-99 8:35 44.9 13.38 8,974 6,140 5.70 9.36 -2.821 1.645 12-21-99 9:42 46.0 14.93 8,944 6,310 6.42 8.79 -3.008 1.778

12-21-99 15:21 46.2 16.23 8,911 6,400 7.20 8.50 -3.097 1.801 12-22-99 16:47

** 47.3 20.31 8,819 6,520 9.39 8.11 -3.510 1.980

12-29-99 11:31 54.1 20.31 8,815 7,060 9.51 6.48 -3.831 2.032 01-07-00 12:00 63.1 20.31 8,827 6,700 9.21 7.55 -3.873 2.038 04-12-00 12:00 161.1 20.31 8,849 6,470 8.68 8.27 -3.930 2.118

05-22-00 198.6 20.31 8,856 5,800 8.47 10.54 -3.971 2.120 06-19-00 226.6 20.31 8,840 5,250 8.81 12.64 -3.778 2.124

07-24-00 *** 261.6 20.31 8,845 5,210 8.69 12.80 -3.843 2.224 10-23-00 352.6 20.31 8,798 4,020 9.70 18.40 -4.170 2.331 12-14-00 404.6 20.31 8,833 6,040 9.03 9.70 -4.403 2.375 02-07-01 459.6 20.31 8,790 6,560 10.08 7.99 -4.653 2.463 04-12-01 523.6 20.31 8,722 5,440 11.62 11.89 NA NA 06-14-01 586.6 20.31 8,718 5,250 11.70 12.64 NA NA 01-29-02 815.6 20.31 8,750 5,830 10.98 10.44 NA NA 06-21-02 958.6 20.31 8,736 5,200 11.27 12.85 NA NA 04-03-03 1,242.6 20.31 8,811 6,070 9.55 9.60 NA NA 06-24-03 1,326.6 20.31 8,771 5,300 10.45 12.44 NA NA 04-28-04 1,635.6 20.31 8,804 6,210 9.73 9.12 -4.825 2.486 04-01-05 1,973.6 20.31 8,807 6,130 9.65 9.39 NA NA



127

Test Pipe #11 (30-in dia. HDPE pipe backfilled in crushed rock; 100.0% relative compaction)



Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

11-05-99 10:00 0.0 -0.67 9,187 4,570 0.00 15.61 -0.170 -0.391 11-05-99 11:00 0.0 0.00 9,182 5,520 0.22 11.58 -0.019 -0.463 11-05-99 13:30 0.1 0.50 9,170 5,040 0.45 13.51 -0.029 -0.417 11-05-99 14:45

* 0.2 1.00 9,129 4,750 1.38 14.78 -0.050 -0.397

12-02-99 11:50 27.1 3.00 9,129 6,640 1.55 7.74 -0.543 0.002 12-07-99 17:50 32.3 5.02 9,062 6,510 3.11 8.15 -0.655 0.046 12-08-99 16:10 33.3 5.90 9,045 6,600 3.52 7.86 -0.694 0.088 12-09-99 09:15 34.0 7.49 9,041 6,670 3.61 7.65 -0.752 0.096 12-09-99 16:47 34.3 10.06 9,032 6,570 3.82 7.96 -0.749 0.105 12-17-99 15:45 42.2 14.61 9,006 6,700 4.44 7.55 NA NA 12-21-99 09:00 46.0 17.02 8,979 6,520 5.05 8.11 -1.194 0.254 12-21-99 15:50 46.2 18.07 8,958 6,620 5.55 7.80 -1.243 0.278 12-22-99 10:45 47.0 20.45 8,928 6,450 6.24 8.34 -1.447 0.400 12-22-99 16:55 47.3 22.69 8,908 6,640 6.72 7.74 -1.553 0.410 12-23-99 12:00 48.1 23.56 8,878 6,700 7.43 7.55 -1.684 0.457 12-24-99 08:30 48.9 28.00 8,829 6,350 8.55 8.66 -1.961 0.570 12-27-99 16:58 52.3 32.49 8,807 6,580 9.08 7.93 -2.233 0.662 12-28-99 08:38 52.9 39.11 8,701 6,820 11.58 7.19 -2.676 0.771 12-29-99 11:36

** 54.1 40.00 8,693 7,080 11.79 6.42 -2.788 0.847

01-07-00 63.1 40.00 8,719 6,740 11.15 7.43 -2.999 0.898 04-14-00 161.1 40.00 8,700 6,350 11.57 8.66 -3.250 0.929 05-22-00 198.6 40.00 8,716 5,850 11.15 10.37 -3.319 0.914 06-19-00 226.6 40.00 8,680 5,190 11.93 12.89 -3.319 0.929

07-24-00 *** 261.6 40.00 8,684 5,140 11.83 13.09 -3.376 1.015 10-23-00 352.6 40.00 8,699 5,290 11.49 12.48 -3.461 1.008 12-14-00 404.6 40.00 8,763 6,240 10.08 9.02 -3.536 0.981 02-07-01 459.6 40.00 8,741 6,490 10.62 8.21 -3.585 1.004 04-12-01 523.6 40.00 8,631 5,310 13.09 12.40 -3.593 1.020 06-14-01 586.6 40.00 8,633 5,060 13.01 13.43 -3.567 1.016 01-29-02 815.6 40.00 8,687 5,620 11.81 11.21 NA 1.005 06-21-02 958.6 40.00 8,639 5,020 12.87 13.59 NA 1.117 04-09-03 1250.6 40.00 8,720 5,850 11.06 10.37 NA 1.135 06-24-03 1326.6 40.00 8,646 5,030 12.71 13.55 NA NA 04-28-04 1635.6 40.00 8,696 5,640 11.60 11.13 -3.368 1.075 04-01-05 1973.6 40.00 8,705 5,750 11.40 10.73 NA NA



128




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


11-01-99 14:30 0.0 -2.00 9265 7180 0.00 6.14 -0.017 -0.012 11-01-99 16:10 0.1 -1.33 9262 6690 0.04 7.59 -0.017 -0.110 11-05-99 10:00 3.8 -0.67 9249 7200 0.36 6.08 -0.170 -0.391 11-05-99 11:00 3.9 0.00 9247 6950 0.39 6.80 -0.019 -0.463 11-05-99 13:30 4.0 0.50 9241 6740 0.51 7.43 -0.029 -0.417 11-05-99 14:45

* 4.0 1.00 9224 6330 0.87 8.73 -0.050 -0.397

12-02-99 11:50 30.9 3.00 9207 6000 1.23 9.84 -0.543 0.002 12-07-99 17:50 36.1 5.02 9156 5980 2.37 9.91 -0.655 0.046 12-08-99 16:10 37.1 5.90 9129 6050 2.98 9.66 -0.694 0.088 12-09-99 09:15 37.8 7.49 9107 6130 3.48 9.39 -0.752 0.096 12-09-99 16:20 38.1 10.06 9086 6030 3.94 9.73 NA NA 12-09-99 16:47 38.1 10.06 9059 5920 4.54 10.12 -0.749 0.105 12-16-99 08:59 44.8 11.69 9033 6290 5.15 8.86 NA NA 12-21-99 09:00 49.8 17.02 8918 6170 7.71 9.26 -1.194 0.254 12-21-99 15:50 50.1 18.07 8885 6240 8.46 9.02 -1.243 0.278 12-22-99 10:45 50.8 20.45 8830 6190 9.69 9.19 -1.447 0.400 12-22-99 16:55 51.1 22.69 8786 6290 10.68 8.86 -1.553 0.410 12-23-99 12:00 51.9 23.56 8736 6320 11.80 8.76 -1.684 0.457 12-24-99 08:30 52.8 28.00 8652 5960 13.66 9.98 -1.961 0.570 12-27-99 16:58 56.1 32.49 8596 6440 14.95 8.37 -2.233 0.662 12-28-99 08:38 56.8 39.11 8455 6570 18.11 7.96 -2.676 0.771 12-29-99 11:36

** 57.9 40.00 8446 6790 18.33 7.28 -2.788 0.847

01-07-00 66.9 40.00 8466 6430 17.86 8.40 -2.999 0.898 04-14-00 164.9 40.00 8455 6240 18.09 9.02 -3.250 0.929 05-22-00 202.4 40.00 8468 5750 17.77 10.73 -3.319 0.914 06-19-00 230.4 40.00 8427 5200 18.65 12.85 -3.319 0.929

07-24-00 *** 265.4 40.00 8427 5150 18.64 13.05 -3.376 1.015 10-23-00 356.4 40.00 8437 5280 18.43 12.52 -3.461 1.008 12-14-00 408.4 40.00 8509 6210 16.88 9.12 -3.536 0.981 02-07-01 463.4 40.00 8479 6340 17.56 8.69 -3.585 1.004 04-12-01 527.4 40.00 8388 5270 19.53 12.56 -3.593 1.020 06-14-01 590.4 40.00 8397 5100 19.31 13.26 -3.567 1.016 01-29-02 819.4 40.00 8451 5650 18.14 11.09 NA NA 06-21-02 962.4 40.00 8420 5070 18.79 13.38 NA 1.117 04-09-03 1254.4 40.00 8521 5850 16.59 10.37 NA NA 06-24-03 1330.4 40.00 8440 5050 18.34 13.47 NA 1.135 04-28-04 1639.4 40.00 8494 5670 17.18 11.02 -3.368 1.075 04-01-05 1977.4 40.00 8495 5770 17.16 10.65 NA NA

[Notes] “NA” = Data Not Available * End of Initial Backfilling ** End of Embankment Construction *** End of Initial Monitoring Phase + Pipe deflections are all relative to the initial shape the pipe had at the

beginning of the initial backfilling process.

129




Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-29-99 13:00 0.0 -0.67 9121 6350 0.00 8.66 0.552 -0.146 10-29-99 14:30 0.1 0.00 9114 5550 0.11 11.47 0.729 -0.297 11-01-99 10:00 2.9 0.50 9100 5250 0.42 12.64 0.476 -0.306 11-01-99 11:30

* 2.9 1.00 9081 5020 0.85 13.59 0.479 -0.292

12-02-99 14:45 34.1 3.00 9059 6940 1.52 6.83 0.086 -0.091 12-09-99 09:45 40.9 7.35 8874 6690 5.91 7.59 -0.466 0.229 12-09-99 17:29 41.2 8.00 8872 6610 5.95 7.83 -0.493 0.251 12-15-99 16:30 47.1 11.36 8871 6500 5.97 8.18 -0.553 0.252 12-16-99 16:47 48.2 13.17 8858 6740 6.29 7.43 -0.593 0.253 12-17-99 08:25 48.8 16.15 8827 6730 7.03 7.46 -0.637 0.254 12-20-99 08:00 51.8 17.49 8818 6510 7.23 8.15 -0.896 0.329 12-21-99 17:12

** 53.2 20.07 8794 6640 7.81 7.74 -0.953 0.340

12-29-99 12:55 61.0 20.07 8764 6870 8.54 7.04 -1.110 0.335 01-07-00 10:30 69.9 20.07 8759 6550 8.64 8.02 -1.202 0.396

04-12-00 166.0 20.07 8755 6470 8.73 8.27 -1.313 0.372 05-22-00 205.5 20.07 8753 5770 8.73 10.65 -1.337 0.373 06-19-00 233.5 20.07 8713 5090 9.63 13.30 NA NA

07-24-00 *** 268.5 20.07 8709 4850 9.70 14.33 NA NA 10-23-00 359.5 20.07 8733 4850 9.13 14.33 -1.276 0.418 12-11-01 408.5 20.07 8800 5480 7.59 11.74 -1.343 0.374 02-07-01 466.5 20.07 8814 6020 7.29 9.77 -1.384 0.346 03-12-01 499.5 20.07 8796 6000 7.72 9.84 -1.416 0.350 04-12-01 530.5 20.07 8734 5220 9.14 12.76 -1.421 0.369 06-14-01 593.5 20.07 8695 4750 10.03 14.78 -1.463 0.352 01-29-02 822.5 20.07 8791 5440 7.80 11.89 -1.542 0.302 06-21-02 965.5 20.07 8733 4960 9.14 13.85 NA NA 04-09-03 1257.5 20.07 8851 6080 6.42 9.56 -1.519 0.333 06-24-03 1333.5 20.07 8737 4930 9.04 13.98 NA NA 04-28-04 1642.5 20.07 8810 5890 7.38 10.22 NA NA 04-01-05 1980.5 20.07 8825 5920 7.02 10.12 NA NA



130




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-29-99 10:30 0.0 -2.00 8917 6230 0.00 9.06 0.072 0.060 10-29-99 11:20 0.0 -1.33 8895 4470 0.44 16.09 0.228 0.029 10-29-99 13:00 0.1 -0.67 8893 4700 0.51 15.00 0.552 -0.146 10-29-99 14:30 0.2 0.00 8896 4430 0.41 16.28 0.729 -0.297 11-01-99 10:00 3.0 0.50 8895 4930 0.47 13.98 0.476 -0.306 11-01-99 11:30

* 3.0 1.00 8885 5010 0.73 13.64 0.479 -0.292

12-02-99 14:45 34.2 3.00 8880 5950 0.92 10.01 0.086 -0.091 12-07-99 15:45 39.2 4.26 8834 5870 2.08 10.29 -0.245 0.085 12-08-99 16:35 40.3 5.47 8800 6010 2.94 9.80 -0.386 0.216 12-09-99 09:45 41.0 7.35 8777 6050 3.53 9.66 -0.466 0.229 12-09-99 17:29 41.3 8.00 8764 6050 3.86 9.66 -0.493 0.250 12-15-99 16:30 47.3 11.36 8728 6020 4.77 9.77 -0.553 0.252 12-16-99 16:47 48.3 13.17 8693 6260 5.66 8.96 -0.593 0.253 12-17-99 08:25 48.9 16.15 8646 6260 6.85 8.96 -0.637 0.254 12-20-99 08:00 51.9 17.49 8620 5990 7.49 9.87 -0.896 0.329 12-21-99 09:00 52.9 17.49 8615 6200 7.63 9.16 -0.896 0.329 12-21-99 17:12

** 53.3 20.07 8578 6240 8.57 9.02 -0.953 0.340

12-29-99 12:55 61.1 20.07 8564 6540 8.94 8.05 -1.110 0.335 01-07-00 10:30 70.0 20.07 8551 6270 9.25 8.92 -1.202 0.396

04-12-00 166.1 20.07 8513 6290 10.22 8.86 -1.313 0.372 05-22-00 205.6 20.07 8557 5680 9.07 10.98 -1.337 0.373 06-19-00 233.6 20.07 8483 5080 10.90 13.34 NA NA

07-24-00 *** 268.6 20.07 8483 4920 10.89 14.02 NA NA 10-23-00 359.6 20.07 8494 4930 10.61 13.98 -1.276 0.418 12-11-01 408.6 20.07 8547 5590 9.31 11.32 -1.343 0.374 02-07-01 466.6 20.07 8563 6090 8.94 9.53 -1.384 0.346 03-12-01 499.6 20.07 8549 6010 9.29 9.80 -1.416 0.350 04-12-01 530.6 20.07 8496 5240 10.53 12.68 -1.421 0.369 06-14-01 593.6 20.07 8476 4940 11.06 13.94 -1.463 0.352 01-29-02 822.6 20.07 8536 5470 9.58 11.78 -1.542 0.302 06-21-02 965.6 20.07 8503 5010 10.39 13.64 NA NA 04-09-03 1257.6 20.07 8590 6170 8.26 9.26 -1.519 0.333 06-24-03 1333.6 20.07 8506 4900 10.30 14.11 NA NA 04-28-04 1642.6 20.07 8561 5870 8.98 10.29 NA NA 04-01-05 1980.6 20.07 8569 5940 8.78 10.05 NA NA



131



Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-26-99 13:00 0.0 -0.67 8823 3648 0.00 20.54 0.778 -0.472 10-26-99 15:15 0.1 0.00 8806 4430 0.33 16.28 0.784 -0.476 10-26-99 17:00 0.2 0.50 8775 7150 0.97 6.22 0.791 -0.472 10-27-99 8:00

* 0.8 1.00 8736 7440 1.65 5.42 0.598 -0.505

12-02-99 12:10 37.0 3.00 8633 7320 3.42 5.75 0.510 -0.623 12-07-99 18:00 42.2 4.50 8586 6870 4.22 7.04 0.444 -0.669 12-08-99 7:00 42.8 5.02 8571 7040 4.48 6.54 0.410 -0.617

12-08-99 16:10 43.1 6.95 8504 7250 5.65 5.94 NA NA 12-09-99 16:57 44.2 8.00 8456 7080 6.47 6.42 0.221 -0.551 12-16-99 16:08 51.1 11.39 8468 7200 6.27 6.08 NA NA 12-20-99 8:40 54.8 13.12 8452 7160 6.54 6.20 -0.107 -0.489 12-21-99 9:53 55.9 14.70 8436 7070 6.81 6.45 -0.300 -0.407

12-21-99 15:26 56.1 15.86 8407 7110 7.32 6.34 -0.377 -0.380 12-22-99 10:50

** 56.9 20.47 8341 6970 8.45 6.74 -0.763 -0.237

12-23-99 57.9 20.47 8326 7400 8.72 5.53 -0.890 -0.197 12-29-99 64.0 20.47 8328 8040 8.70 3.85 -1.003 -0.197 01-07-00 72.9 20.47 8346 7380 8.38 5.58 -1.038 -0.174 04-14-00 171.0 20.47 8344 6600 8.39 7.86 -1.302 0.032 05-22-00 208.5 20.47 8363 5600 8.03 11.28 -1.259 0.072 06-19-00 236.5 20.47 8362 4920 8.02 14.02 -1.351 0.100

07-24-00 *** 271.5 20.47 8385 4870 7.62 14.24 -1.464 0.162 10-23-00 362.5 20.47 8372 4890 7.84 14.15 -1.645 0.100 12-14-00 414.5 20.47 8474 6380 6.14 8.56 -1.758 0.028 02-07-01 469.5 20.47 8419 7000 7.11 6.66 -1.820 0.036 04-12-01 533.5 20.47 8131 4540 11.99 15.75 -1.959 -0.043 06-14-01 596.5 20.47 8142 4770 11.81 14.69 -1.979 -0.009 01-29-02 825.5 20.47 8218 5790 10.54 10.58 NA -0.032

[Notes] “NA” = Data Not Available. * End of Initial Backfilling ** End of Construction *** End of Initial Monitoring Phase


132



Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-25-99 12:00 0.0 -2.67 9073 3400 0.00 22.11 0.326 0.053 10-26-99 9:54 0.9 -1.33 9088 7020 0.04 6.60 0.578 -0.244

10-26-99 13:00 1.0 -0.67 9087 6610 0.03 7.83 0.778 -0.472 10-26-99 15:15 1.1 0.00 9081 6340 0.15 8.69 0.784 -0.476 10-26-99 17:00 1.2 0.50 9069 5950 0.40 10.01 0.791 -0.472 10-27-99 8:00

* 1.8 1.00 9056 5970 0.70 9.94 0.598 -0.505

12-02-99 12:10 38.0 3.00 9010 6720 1.84 7.49 0.510 -0.623 12-07-99 18:00 43.3 4.50 8986 6470 2.38 8.27 0.444 -0.669 12-08-99 16:10 44.2 6.95 8943 6660 3.40 7.68 0.410 -0.617 12-09-99 9:20 44.9 9.67 8917 6850 4.02 7.10 0.283 -0.604

12-09-99 16:55 45.2 9.67 8876 6660 4.96 7.68 0.221 -0.551 12-13-99 16:25 49.2 11.39 8832 6730 5.12 8.60 NA NA 12-16-99 16:08 52.2 13.12 8796 6360 5.99 7.46 -0.107 -0.489 12-20-99 8:40 55.9 14.70 8764 6770 6.80 8.63 -0.300 -0.407

12-21-99 15:26 57.1 20.47 8731 6820 8.36 7.19 -0.377 -0.380 12-22-99 16:58

** 58.2 20.47 8617 7000 11.03 6.66 -0.763 -0.237

12-29-99 11:50 65.0 20.47 8620 7810 11.02 4.44 -1.003 -0.197 01-07-00 11:20 74.0 20.47 8649 7180 10.30 6.14 -1.038 -0.174 04-14-00 12:00 172.0 20.47 8672 6580 9.71 7.93 -1.302 0.032

06-01-00 219.5 20.47 8689 5090 9.18 13.30 -1.259 0.072 06-19-00 237.5 20.47 8712 4930 8.63 13.98 -1.351 0.100

07-24-00 *** 272.5 20.47 8710 4900 8.67 14.11 -1.464 0.162 10-23-00 363.5 20.47 8678 5030 9.43 13.55 -1.645 0.100 12-14-00 415.5 20.47 8742 6690 8.09 7.59 -1.758 0.028 02-07-01 470.5 20.47 8707 7130 8.94 6.28 -1.820 0.036 04-12-01 534.5 20.47 8521 4810 13.07 14.51 -1.959 -0.043 06-14-01 597.5 20.47 8600 5070 11.26 13.38 -1.979 -0.009 01-29-02 826.5 20.47 8653 6110 10.12 9.46 NA -0.032 06-21-02 969.5 20.47 8621 5000 10.76 13.68 NA NA 04-09-03 1261.5 20.47 8693 6500 9.22 8.18 NA NA 06-24-03 1337.5 20.47 8645 6070 10.30 9.60 NA NA 04-28-04 1646.5 20.47 8733 6030 8.25 9.73 NA NA 04-01-05 1984.5 20.47 8728 6290 8.38 8.86 NA NA



133



Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-26-99 13:00 0.0 -0.67 8787 3600 0.00 20.84 0.836 -0.471 10-26-99 15:15 0.1 0.00 8791 5160 0.04 13.01 0.873 -0.498 10-26-99 17:00 0.2 0.50 8775 7220 0.52 6.03 0.867 -0.495 10-27-99 8:30

* 0.8 1.00 8745 7370 1.19 5.61 0.702 -0.502

12-02-99 12:10 37.0 4.00 8682 7080 2.58 6.42 0.452 -0.360 12-09-99 9:16 43.8 7.15 8548 6990 5.55 6.69 0.165 -0.234

12-09-99 16:54 44.2 9.71 8528 6860 5.99 7.07 0.177 -0.227 12-16-99 16:08 51.1 11.79 8501 7020 6.60 6.60 -0.075 -0.160 12-20-99 8:40 54.8 14.61 8468 6590 7.31 7.89 -0.179 -0.093 12-21-99 9:53 55.9 16.60 8445 6830 7.84 7.16 -0.317 -0.066

12-21-99 15:24 56.1 17.97 8421 6900 8.37 6.95 -0.359 -0.038 12-22-99 16:59 57.2 22.15 8368 7010 9.56 6.63 -0.596 0.035 12-23-99 9:35 57.9 23.47 8332 7070 10.36 6.45 -0.695 0.064 12-24-99 8:35 58.8 25.07 8285 6760 11.39 7.37 -0.907 0.137

12-27-99 11:06 61.9 29.72 8273 7500 11.69 5.25 -1.054 0.138 12-27-99 16:59 62.2 32.31 8241 7170 12.39 6.17 -1.071 0.142 12-28-99 8:25 62.8 39.15 8165 7300 14.08 5.80 -1.420 0.181

12-29-99 11:36 **

63.9 40.00 8149 7570 14.45 5.07 -1.484 0.189

04-14-00 12:00 171.0 40.00 8191 6480 13.46 8.24 -1.562 0.133 05-22-00 208.5 40.00 8212 5670 12.95 11.02 -1.627 0.104 06-19-00 236.5 40.00 8195 4970 13.28 13.81 -1.565 0.211

07-24-00 *** 271.5 40.00 8191 4890 13.36 14.15 -1.585 0.185 10-23-00 362.5 40.00 8210 5210 12.96 12.80 -1.658 0.177 12-14-00 414.5 40.00 8308 6540 10.86 8.05 -1.733 0.155 02-07-01 469.5 40.00 8278 6960 11.55 6.77 -1.785 0.131 04-12-01 533.5 40.00 8247 4790 12.11 14.60 -1.762 0.141 06-14-01 596.5 40.00 8537 4750 14.78 -1.731 0.166 01-29-02 825.5 40.00 8329 5820 10.36 10.47 -1.833 -0.047 06-21-02 968.5 40.00 8292 4890 11.12 14.15 NA NA 04-09-03 1260.5 40.00 8374 6400 9.39 8.50 -1.462 0.124 06-24-03 1336.5 40.00 8291 4880 11.14 14.20 NA NA



134

Test Pipe #14 (42-in dia. HDPE pipe backfilled in sand; 94.9% relative compaction) Lateral Soil Pressure Measured at Pipe Springline Pressure Cell: Serial # 8-1278 (G = 0.023684; K = - 0.01824)


Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-25-99 15:30 0.0 -2.00 8964 5290 0.11 12.48 0.395 0.097 10-25-99 17:30 0.1 -1.33 8962 6940 0.30 6.83 0.509 -0.132 10-26-99 13:00 0.9 -0.67 8966 6650 0.19 7.71 0.836 -0.471 10-26-99 15:15 1.0 0.00 8967 6380 0.14 8.56 0.873 -0.498 10-26-99 17:00 1.1 0.50 8953 5800 0.42 10.54 0.867 -0.495 10-27-99 8:30

* 1.7 1.00 8946 5840 0.59 10.40 0.702 -0.502

12-02-99 12:20 37.9 5.03 8937 6340 0.84 8.69 NA NA 12-07-99 18:00 43.1 5.03 8921 6270 1.21 8.92 0.333 -0.312 12-08-99 7:00 43.7 5.93 8896 6350 1.80 8.66 0.259 -0.244 12-09-99 9:16 44.8 7.15 8879 6470 2.21 8.27 0.165 -0.234

12-09-99 16:54 45.1 9.71 8866 6390 2.51 8.53 0.177 -0.227 12-16-99 16:08 52.0 11.79 8838 6520 3.18 8.11 -0.075 -0.160 12-20-99 8:40 55.7 14.61 8806 6590 3.93 7.89 -0.179 -0.093 12-21-99 9:53 56.8 16.60 8777 6490 4.60 8.21 -0.317 -0.066

12-21-99 15:24 57.0 17.97 8762 6550 4.96 8.02 -0.359 -0.038 12-22-99 10:50 57.8 20.19 8729 6520 5.73 8.11 -0.514 0.002 12-22-99 16:59 58.1 22.15 8697 6640 6.49 7.74 -0.596 0.035 12-23-99 9:35 58.8 23.47 8664 6660 7.27 7.68 -0.695 0.064 12-24-99 8:35 59.7 25.07 8610 6590 8.53 7.89 -0.907 0.137

12-27-99 16:59 63.1 32.31 8580 6690 9.24 7.59 -1.071 0.142 12-28-99 8:25 63.7 39.15 8481 7060 11.58 6.48 -1.420 0.181

12-29-99 11:37 **

64.9 40.00 8469 7260 11.88 5.91 -1.484 0.189

4-14-00 12:00 171.9 40.00 8585 6360 9.09 8.63 -1.562 0.133 5-22-00 209.4 40.00 8609 5610 8.47 11.24 -1.627 0.104 6-19-00 237.4 40.00 8579 4960 9.10 13.85 -1.565 0.211

7-24-00 *** 272.4 40.00 8564 4950 9.45 13.89 -1.585 0.185 10-23-00 363.4 40.00 8560 5200 9.57 12.85 -1.658 0.177 12-14-00 415.4 40.00 8623 6560 8.22 7.99 -1.733 0.155 02-07-01 470.4 40.00 8599 6870 8.80 7.04 -1.785 0.131 04-12-01 534.4 40.00 8526 4620 10.31 15.37 -1.762 0.141 06-14-01 597.4 40.00 8285 4710 15.97 14.96 -1.731 0.166 1-29-02 826.4 40.00 8585 5910 9.05 10.15 -1.833 -0.047 6-21-02 969.4 40.00 8555 4940 9.66 13.94 NA NA 4-09-03 1261.4 40.00 8622 6020 8.20 9.77 -1.462 0.124



135




Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-21-99 15:00 0.0 -0.67 8845 5680 0.00 10.98 0.385 -0.537 10-22-99 7:50 0.7 0.00 8836 5740 0.21 10.76 0.377 -0.619 10-22-99 8:41 0.7 0.50 8809 6160 0.87 9.29 0.229 -0.599

10-22-99 10:08 *

0.8 1.00 8785 6000 1.42 9.84 0.200 -0.586

12-02-99 14:40 42.0 3.00 8723 7220 2.94 6.03 -0.078 -0.552 12-09-99 9:45 48.8 6.81 8561 7010 6.71 6.63 -0.372 -0.430

12-09-99 17:34 49.1 9.18 8546 6980 7.06 6.72 -0.373 -0.425 12-15-99 16:35 55.1 11.29 8549 6710 6.97 7.52 -0.450 -0.410 12-16-99 16:50 56.1 13.20 8547 6950 7.03 6.80 -0.553 -0.387 12-17-99 8:20 56.7 16.20 8533 7020 7.36 6.60 -0.689 -0.335 12-20-99 8:00 59.7 17.69 8514 6720 7.79 7.49 -0.739 -0.309

12-21-99 17:17 **

61.1 20.02 8482 6920 8.55 6.89 -0.862 -0.303

12-29-99 12:56 68.9 20.02 8443 7390 9.48 5.55 -1.108 -0.263 1-07-00 10:40 77.8 20.02 8454 6920 9.20 6.89 -1.176 -0.242 4-12-00 12:00 173.9 20.02 8468 6620 8.85 7.80 -1.254 -0.213

5-22-00 213.4 20.02 8466 5710 8.84 10.87 -1.264 -0.230 6-19-00 241.4 20.02 8440 5020 9.39 13.59 -1.143 -0.123

7-24-00 *** 276.4 20.02 8432 4860 9.56 14.29 -1.182 -0.151 10-23-00 367.4 20.02 8447 4830 9.21 14.42 -1.205 -0.144 12-11-00 416.4 20.02 8522 5810 7.54 10.51 -1.209 -0.161 2-07-01 474.4 20.02 8533 6470 7.33 8.27 -1.255 -0.184 4-12-01 538.4 20.02 8505 5860 7.94 10.33 -1.212 -0.235 6-14-01 601.4 20.02 8406 4850 10.17 14.33 -1.179 -0.226 1-29-02 830.4 20.02 8493 5780 8.21 10.62 -1.511 -0.288 6-21-02 973.4 20.02 8438 4790 9.41 14.60 NA NA 4-09-03 1265.4 20.02 8556 6170 6.77 9.26 -1.475 -0.231 6-24-03 1341.4 20.02 8445 5010 9.27 13.64 NA NA 4-28-04 1650.4 20.02 8510 5750 7.81 10.73 NA NA 4-01-05 1988.4 20.02 8523 6070 7.53 9.60 NA NA



136




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-21-99 12:00 0.0 -2.67 9234 5210 0.00 12.80 -0.117 -0.200 10-21-99 13:20 0.1 -2.00 9228 5320 0.15 12.36 0.078 -0.219 10-21-99 14:00 0.1 -1.33 9216 5260 0.42 12.60 0.264 -0.399 10-21-99 15:00 0.1 -0.67 9217 5080 0.38 13.34 0.385 -0.537 10-26-99 15:15 5.1 0.00 9215 4780 0.40 14.64 0.377 -0.619 10-26-99 17:00 5.2 0.50 9210 5190 0.55 12.89 0.229 -0.599 10-27-99 8:00

* 5.8 1.00 9201 5160 0.75 13.01 0.200 -0.586

12-02-99 14:40 42.1 3.00 9198 6280 0.90 8.89 -0.078 -0.552 12-07-99 12:00 47.0 4.36 9167 6190 1.60 9.19 -0.212 -0.527 12-08-99 16:30 48.2 5.49 9130 6370 2.46 8.60 -0.280 -0.439 12-09-99 9:45 48.9 6.81 9093 6410 3.31 8.47 -0.372 -0.430

12-15-99 16:35 55.2 11.29 9031 6310 4.73 8.79 -0.450 -0.410 12-16-99 16:50 56.2 13.20 9016 6520 5.09 8.11 -0.553 -0.387 12-17-99 8:20 56.8 16.20 8991 6610 5.67 7.83 -0.689 -0.335 12-20-99 8:00 59.8 17.69 8923 6410 6.60 8.47 -0.739 -0.309

12-21-99 17:15 **

61.2 20.02 8920 6560 7.29 7.99 -0.862 -0.303

12-29-99 12:56 69.0 20.02 8881 7110 8.22 6.34 -1.108 -0.263 1-07-00 10:40 77.9 20.02 8852 6670 8.86 7.65 -1.176 -0.242 4-12-00 12:00 174.0 20.02 8858 6450 8.71 8.34 -1.254 -0.213

5-22-00 213.5 20.02 8847 5620 8.91 11.21 -1.264 -0.230 6-19-00 241.5 20.02 8812 4950 9.67 13.89 -1.143 -0.123

07-24-00 *** 276.5 20.02 8811 4830 9.68 14.42 -1.182 -0.151 10-23-00 367.5 20.02 8817 4880 9.55 14.20 -1.205 -0.144 12-11-00 416.5 20.02 8882 5950 8.13 10.01 -1.209 -0.161 02-07-01 474.5 20.02 8891 6580 7.96 7.93 -1.255 -0.184 04-12-01 538.5 20.02 8818 5340 9.56 12.28 -1.212 -0.235 06-14-01 601.5 20.02 8802 4840 9.89 14.37 -1.179 -0.226 01-29-02 830.5 20.02 8869 5760 8.42 10.69 -1.511 -0.288 06-21-02 973.5 20.02 8821 4890 9.46 14.15 NA NA 04-09-03 1265.5 20.02 8903 6200 7.66 9.16 -1.475 -0.231 06-24-03 1341.5 20.02 8832 5020 9.22 13.59 NA NA 04-28-04 1650.5 20.02 8883 5970 8.11 9.94 NA NA 04-01-05 1988.5 20.02 8893 6090 7.89 9.53 NA NA



137




Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-08-99 15:00 0.0 -0.75 8965 4870 0.00 14.24 0.948 -0.699 10-12-99 15:00

* 4.0 1.00 8938 3835 0.45 19.43 1.799 -1.515

12-02-99 12:20 54.9 4.00 8922 7350 0.79 5.66 NA NA 12-09-99 9:25 61.8 6.80 8840 7230 2.22 6.00 1.041 -1.299

12-09-99 17:02 62.1 8.00 8787 7160 3.14 6.20 NA NA 12-13-99 16:30 66.1 9.67 8782 6760 3.23 7.37 0.961 -1.259 12-16-99 16:11 69.0 11.26 8755 7050 3.70 6.51 NA NA 12-20-99 8:45 72.7 13.06 8699 6700 4.67 7.55 0.631 -1.184

12-21-99 10:02 73.8 14.72 8679 7010 5.03 6.63 0.379 -1.104 12-22-99 17:01

** 75.1 20.13 8457 7150 8.91 6.22 -0.177 -0.928

12-29-99 12:00 81.9 20.13 8487 7190 8.38 6.11 -0.452 -0.864 1-07-00 11:25 90.9 20.13 8510 7290 7.98 5.83 -0.577 -0.910 4-14-00 12:00 188.9 20.13 8399 6630 9.91 7.77 -0.902 -0.855

5-22-00 226.4 20.13 8405 5530 9.79 11.55 -1.103 -0.900 6-19-00 254.4 20.13 8400 4870 9.87 14.24 -1.104 -0.872

7-24-00 *** 289.4 20.13 8403 4810 9.81 14.51 -1.168 -0.896 10-23-00 380.4 20.13 8398 4820 9.90 14.46 -1.168 -0.916 12-14-00 432.4 20.13 8539 6270 7.46 8.92 -1.270 -0.890 2-07-01 487.4 20.13 8475 6850 8.59 7.10 -1.422 -0.939 4-12-01 551.4 20.13 8274 5000 12.07 13.68 -1.475 -0.947 6-14-01 614.4 20.13 8319 4780 11.28 14.64 -1.503 -0.986 1-29-02 843.4 20.13 8346 5690 10.82 10.95 -1.636 -0.939 6-21-02 986.4 20.13 8293 4830 11.73 14.42 -1.700 -0.904 4-09-03 1278.4 20.13 8328 6100 11.14 9.49 -1.710 -0.906 6-24-03 1354.4 20.13 8223 4740 12.95 14.82 -1.729 -0.906 4-28-04 1663.4 20.13 8279 5840 12.00 10.40 -1.616 -1.134 4-01-05 2001.4 20.13 8334 5960 11.04 9.98 NA NA



138




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-07-99 9:00 0.0 -2.75 8765 2605 0.00 28.19 NA NA 10-08-99 9:00 1.0 -2.09 8767 5650 0.14 11.09 0.460 -0.156

10-08-99 12:00 1.1 -1.42 8768 5530 0.12 11.55 0.523 -0.506 10-08-99 15:00 1.3 -0.75 8774 5250 0.01 12.64 0.948 -0.699 10-12-99 9:00 5.0 0.00 8772 4930 0.03 13.98 0.984 -0.708

10-12-99 12:00 5.1 0.50 8758 4630 0.24 15.33 1.500 -1.322 10-12-99 15:00

* 5.3 1.00 8751 4530 0.35 15.80 1.800 -1.515

12-02-99 12:20 56.1 4.00 8581 6880 3.15 7.01 NA NA 12-07-99 18:05 61.4 5.11 8505 6440 4.36 8.37 1.218 -1.398 12-08-99 7:00 61.9 5.61 8505 6800 4.37 7.25 1.164 -1.362 12-09-99 9:25 63.0 6.80 8419 6820 5.74 7.19 1.041 -1.299

12-09-99 17:02 63.3 8.00 8343 6560 6.95 7.99 NA NA 12-16-99 16:11 70.3 11.26 8280 6670 7.96 7.65 NA NA 12-20-99 8:45 74.0 13.06 8237 6310 8.64 8.79 0.631 -1.184

12-21-99 10:02 75.0 14.72 8161 6840 9.87 7.13 0.379 -1.104 12-21-99 15:30 75.3 15.58 8108 6850 10.72 7.10 0.322 -1.093 12-22-99 17:01

** 76.3 20.13 7873 7060 14.49 6.48 -0.177 -0.928

12-29-99 12:00 83.1 20.13 7890 7830 14.23 4.38 -0.452 -0.864 1-07-00 11:25 92.1 20.13 7969 7190 12.95 6.11 -0.577 -0.910 4-14-00 12:00 190.1 20.13 7811 6350 15.46 8.66 -0.902 -0.855

5-22-00 227.6 20.13 7807 5320 15.48 12.36 -1.103 -0.900 6-19-00 255.6 20.13 7795 4700 15.65 15.00 -1.104 -0.872

7-24-00 *** 290.6 20.13 7791 4680 15.71 15.10 -1.168 -0.896 10-23-00 381.6 20.13 7810 4900 15.42 14.11 -1.168 -0.916 12-14-00 433.6 20.13 7941 6780 13.39 7.31 -1.270 -0.890 2-07-01 488.6 20.13 7868 7310 14.57 5.77 -1.422 -0.939 4-12-01 552.6 20.13 7705 4830 17.10 14.42 -1.475 -0.947 6-14-01 615.6 20.13 7724 4680 16.79 15.10 -1.503 -0.986 1-29-02 844.6 20.13 7772 5920 16.07 10.12 -1.636 -0.939 6-21-02 987.6 20.13 7727 4740 16.74 14.82 -1.700 -0.904 4-09-03 1279.6 20.13 7814 6130 15.40 9.39 -1.710 -0.906 6-24-03 1355.6 20.13 7715 4930 16.94 13.98 -1.729 -0.906 4-28-04 1664.6 20.13 7772 5850 16.06 10.37 -1.616 -1.134 4-01-05 2002.6 20.13 7809 5900 15.47 10.19 NA NA



139




Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-14-99 9:00 0.0 0.00 9292 4590 0.00 15.51 0.330 -0.416 10-14-99 12:00 0.1 0.50 9282 4940 0.19 13.94 0.345 -0.415 10-14-99 16:00

* 0.3 1.00 9247 4330 1.06 16.78 0.329 -0.410

12-13-99 16:30 60.3 8.00 9066 7210 4.94 6.05 -1.341 0.037 12-16-99 9:03 63.0 9.92 9046 7070 5.40 6.45 -1.540 0.080

12-17-99 15:52 64.3 14.14 8989 7240 6.69 5.97 -1.929 0.189 12-21-99 10:00 68.0 15.87 8967 7080 7.20 6.42 -2.252 0.256 12-21-99 15:35 68.3 17.95 8928 7200 8.09 6.08 -2.395 0.296 12-22-99 15:55 69.3 19.97 8915 7060 8.39 6.48 -2.657 0.380 12-22-99 17:03 69.3 21.99 8870 7270 9.40 5.89 -2.863 0.429 12-23-99 9:45 70.0 24.74 8835 7300 10.20 5.80 NA NA 12-24-99 8:35 71.0 28.04 8789 7150 11.26 6.22 NA NA

12-27-99 17:02 74.3 32.10 8755 7410 12.02 5.50 -3.875 0.632 12-28-99 8:20 75.0 39.53 8707 7610 13.10 4.96 -4.591 0.833

12-29-00 12:05 **

76.1 40.00 8681 7800 13.68 4.46 -4.756 0.845

1-07-00 11:25 85.1 40.00 8756 7320 12.00 5.75 -5.091 0.838 4-14-00 12:00 183.1 40.00 8726 6490 12.74 8.21 -5.461 0.793

5-22-00 220.6 40.00 8751 5570 12.24 11.39 -5.528 0.768 6-19-00 248.6 40.00 8734 4350 12.75 16.68 -5.556 0.790

7-24-00 *** 283.6 40.00 8737 4950 12.62 13.89 -5.582 0.775 10-23-00 374.6 40.00 8756 5250 12.16 12.64 -5.597 0.807 12-14-00 426.6 40.00 8897 6810 8.82 7.22 -5.616 0.816 2-07-01 481.6 40.00 8865 7180 9.52 6.14 -5.658 0.804 4-12-01 545.6 40.00 8676 4420 14.07 16.33 -5.698 0.788 6-14-01 608.6 40.00 8690 4510 13.74 15.89 -5.731 0.774 1-29-02 837.6 40.00 8781 5980 11.53 9.91 -5.769 0.760 6-21-02 980.6 40.00 8717 4740 13.10 14.82 NA NA 4-09-03 1272.6 40.00 8834 5980 10.32 9.91 NA NA 6-24-03 1348.6 40.00 8732 4770 12.75 14.69 NA NA 4-28-04 1657.6 40.00 8791 5600 11.33 11.28 NA NA 4-01-05 1995.6 40.00 8829 6040 10.43 9.70 NA NA



140




Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-13-99 9:00 0.0 -2.75 8171 4340 0.00 16.73 NA NA 10-14-99 16:00

* 1.3 1.00 NA NA NA NA 0.329 -0.410

12-02-99 12:20 50.1 3.00 8159 6770 0.36 7.34 NA NA 12-07-99 18:05 55.4 4.30 8111 6520 1.55 8.11 -0.927 -0.087 12-08-99 16:15 56.3 5.37 8069 6660 2.60 7.68 -1.098 -0.033 12-09-99 9:27 57.0 6.77 8061 6760 2.81 7.37 -1.300 0.025

12-13-99 16:30 61.3 8.00 8023 6580 3.75 7.93 -1.341 0.037 12-16-99 9:03 64.0 9.92 7999 6770 4.35 7.34 -1.540 0.080

12-17-99 15:52 65.3 14.14 7943 6900 5.75 6.95 -1.929 0.189 12-20-99 16:30 68.3 14.14 7919 6610 6.34 7.83 -2.039 0.220 12-21-99 10:00 69.0 15.87 7906 6870 6.67 7.04 -2.252 0.256 12-21-99 15:35 69.3 17.95 7872 6960 7.52 6.77 -2.395 0.296 12-22-99 15:55 70.3 19.97 7834 6950 8.47 6.80 -2.657 0.380 12-22-99 17:03 70.3 21.99 7773 7060 9.99 6.48 -2.863 0.429 12-23-99 9:45 71.0 24.74 7721 7110 11.29 6.34 NA NA 12-24-99 8:35 72.0 28.04 7642 6920 13.26 6.89 NA NA

12-27-99 11:09 75.1 29.12 7611 7630 14.04 4.91 -3.747 0.612 12-27-99 17:02 75.3 32.10 7547 7140 15.63 6.25 -3.875 0.632 12-28-99 8:20 76.0 39.53 7400 7540 19.30 5.15 -4.591 0.833

12-29-99 12:05 **

77.1 40.00 7360 7700 20.30 4.72 -4.756 0.845

1-07-00 11:25 86.1 40.00 7443 7150 18.22 6.22 -5.091 0.838 4-14-00 12:00 184.1 40.00 7434 6420 18.43 8.43 -5.461 0.793

5-22-00 221.6 40.00 7466 5420 17.61 11.97 -5.528 0.768 6-19-00 249.6 40.00 7462 4810 17.69 14.51 -5.556 0.790

7-24-00 *** 284.6 40.00 7469 4790 17.52 14.60 -5.582 0.775 10-23-00 375.6 40.00 7487 5130 17.08 13.13 -5.597 0.807 12-14-00 427.6 40.00 7613 6820 13.98 7.19 -5.616 0.816 2-07-01 482.6 40.00 7585 7350 14.69 5.66 -5.658 0.804 4-12-01 546.6 40.00 7429 5060 18.52 13.43 -5.698 0.788 6-14-01 609.6 40.00 7438 4660 18.29 15.19 NA NA 1-29-02 838.6 40.00 7511 6060 16.50 9.63 -5.769 0.760 6-21-02 981.6 40.00 7459 4760 17.77 14.73 NA NA 4-09-03 1273.6 40.00 7562 6030 15.23 9.73 NA NA 6-24-03 1349.6 40.00 7476 4820 17.34 14.46 NA NA 4-28-04 1658.6 40.00 7527 5740 16.10 10.76 NA NA 4-01-05 1996.6 40.00 7556 6130 15.38 9.39 NA NA



141



Days

Cover (ft) VW-

f2 Resistance

(Ω)

Soil Pressure

(psi)

Temp. (°C)

Vertical Horizon.

10-18-99 11:50 0.0 -0.75 8468 4510 0.00 15.89 0.885 -0.895 10-18-99 13:45 0.1 0.00 8463 3850 0.06 19.35 1.018 -0.929 10-18-99 15:00 0.1 0.50 8440 4200 0.47 17.44 1.029 -0.924 10-18-99 16:35

* 0.2 1.00 8402 4400 1.13 16.43 1.004 -0.921

12-02-99 14:30 45.1 3.00 8396 7360 1.32 5.64 0.690 -0.871 12-09-99 9:47 51.9 5.04 8235 7160 4.10 6.20 0.605 -0.871

12-09-99 17:36 52.2 6.90 8225 7090 4.27 6.40 0.485 -0.831 12-15-99 16:35 58.2 10.87 8209 7090 4.54 6.40 0.410 -0.834 12-16-99 16:42 59.2 13.35 8191 7250 4.86 5.94 0.329 -0.827 12-17-99 8:15 59.9 16.20 8165 7360 5.31 5.64 0.245 -0.822 12-20-99 7:55 62.8 17.94 8137 6950 5.78 6.80 0.230 -0.825

12-21-99 17:18 **

64.2 19.74 8139 7290 5.75 5.83 0.167 -0.832

12-29-99 12:58 72.0 19.74 8123 7590 6.04 5.01 0.066 -0.856 1-07-00 10:40 81.0 19.74 8126 7230 5.98 6.00 0.077 -0.884 4-12-00 12:00 177.0 19.74 8100 6650 6.41 7.71 0.039 -0.964

5-22-00 216.5 19.74 8059 5610 7.09 11.24 NA NA 6-19-00 244.5 19.74 8014 4900 7.85 14.11 0.051 -0.984

7-24-00 *** 279.5 19.74 8000 4840 8.09 14.37 0.095 -0.982 10-23-00 370.5 19.74 8020 4870 7.74 14.24 0.091 -0.962 12-10-00 418.5 19.74 8171 6070 5.17 9.60 0.095 -0.920 2-07-01 477.5 19.74 8204 7110 4.63 6.34 0.053 -0.967 4-12-01 541.5 19.74 7963 5250 8.74 12.64 0.082 -0.978 6-14-01 604.5 19.74 7958 4810 8.81 14.51 0.088 -1.014 1-29-02 833.5 19.74 8086 5750 6.63 10.73 0.061 -1.034 6-21-02 976.5 19.74 7999 4850 8.10 14.33 NA NA 4-09-03 1268.5 19.74 8197 6230 4.73 9.06 0.074 -0.998 6-24-03 1344.5 19.74 8009 4690 7.93 15.05 NA NA 4-28-04 1653.5 19.74 8112 5970 6.19 9.94 NA NA 4-01-05 1991.5 19.74 8153 6200 5.05 5.17 NA NA



142



Date & Time

Days

Cover (ft)

VW-f2

Resistance (Ω)

Soil Pressure

(psi)


10-15-99 9:00 0.0 -2.75 7601 3885 0.00 19.15 0.749 -0.466 10-18-99 9:00 3.0 -1.42 7612 6300 0.01 8.82 0.724 -0.783

10-18-99 13:00 3.2 0.00 1.018 -0.929 10-18-99 15:00 3.3 0.50 7601 5590 0.12 11.32 1.029 -0.924 10-18-99 16:35

* 3.3 1.00 7583 5640 0.36 11.13 1.004 -0.921

12-07-99 15:50 53.3 3.97 7569 6460 0.59 8.31 0.620 -0.877 12-09-99 9:47 55.0 5.04 7494 6710 1.61 7.52 0.605 -0.871

12-09-99 17:36 55.4 6.90 7487 6550 1.69 8.02 0.485 -0.831 12-13-99 16:45 59.3 8.94 7477 6400 1.82 8.50 0.492 -0.833 12-15-99 16:35 61.3 10.87 7408 6540 2.74 8.05 0.410 -0.834 12-16-99 16:42 62.3 13.35 7365 6810 3.33 7.22 0.329 -0.827 12-17-99 8:15 63.0 16.20 7302 7040 4.18 6.54 0.245 -0.822 12-20-99 7:55 66.0 17.94 7246 6610 4.91 7.83 0.230 -0.825

12-21-99 17:18 **

67.3 19.74 7240 6980 5.00 6.72 0.167 -0.832

12-29-99 12:58 75.2 19.74 7207 7570 5.47 5.07 0.066 -0.856 1-07-00 10:40 84.1 19.74 7229 7120 5.16 6.31 0.077 -0.884 4-12-00 12:00 180.1 19.74 7203 7120 5.50 6.31 0.039 -0.964

5-22-00 219.6 19.74 7168 5470 5.89 11.78 NA NA 6-19-00 247.6 19.74 7110 4800 6.62 14.55 0.051 -0.984

7-24-00 *** 282.6 19.74 7097 4690 6.78 15.05 0.095 -0.982 10-23-00 373.6 19.74 7126 4910 6.41 14.07 0.091 -0.962 12-10-00 421.6 19.74 7274 6360 4.52 8.63 0.095 -0.920 2-07-01 480.6 19.74 7314 6810 4.01 7.22 0.053 -0.967 4-12-01 544.6 19.74 7055 5030 7.36 13.55 0.082 -0.978 6-14-01 607.6 19.74 7057 4730 7.32 14.87 0.088 -1.014 1-29-02 836.6 19.74 7187 5820 5.65 10.47 0.061 -1.034 6-21-02 979.6 19.74 7106 4800 6.67 14.55 NA NA 4-09-03 1271.6 19.74 7324 6350 3.85 8.66 0.074 -0.998 6-24-03 1347.6 19.74 7108 4640 6.63 15.28 NA NA 4-28-04 1656.6 19.74 7224 5920 5.17 10.12 NA NA 4-01-05 1994.6 19.74 7273 6290 4.53 8.86 NA NA



143

APPENDIX B:

REGRESSION ANALYSIS OF LONG-TERM

PIPE DEFLECTIONS

144

VD = -0.1676Ln(t) + 0.3106R2 = 0.5209(Test Pipe 1)

-3

-2

-1

0

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)

Figure B.1: Regression Analysis of Vertical Deflection Changes over Time (Pipe 1)

HD = 0.1105Ln(t) - 0.56R2 = 0.6258(Test Pipe 1)

-1

-0.5

0

0.5

1

0 500 1000 1500 2000

Elasped Time (days)

Hor

iz. D

efle

ctio

n (%

)

Figure B.2: Regression Analysis of Horizontal Deflection Changes over Time

(Pipe 1)

145

VD = -0.4166Ln(t) + 0.5562R2 = 0.8307(Test Pipe 2)

-3

-2

-1

0

0 200 400 600 800 1000 1200 1400

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = 0.3405Ln(t) - 1.2617R2 = 0.8347(Test Pipe 2)

0

1

2

3

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 2)

146

VD = -0.0837Ln(t) - 1.6507R2 = 0.5822(Test Pipe 3)

-3

-2.5

-2

-1.5

-1

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = 0.1988Ln(t) + 0.7274R2 = 0.8416(Test Pipe 3)

1

1.5

2

2.5

3

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 3)

147

VD = -0.0386Ln(t) - 1.2057R2 = 0.6279(Test Pipe 4)

-2

-1.5

-1

-0.5

0

0 100 200 300 400 500 600

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = -0.0584Ln(t) + 0.9688R2 = 0.1142(Test Pipe 4)

0

0.5

1

1.5

2

0 100 200 300 400 500 600

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 4)

148

VD = -0.6231Ln(t) + 1.9653R2 = 0.7854(Test Pipe 5)

-5

-4

-3

-2

-1

0

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = 0.6568Ln(t) - 2.4845R2 = 0.7734(Test Pipe 5)

0

1

2

3

4

5

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 5)

149

VD = -0.1198Ln(t) - 0.0766R2 = 0.5478(Test Pipe 6)

-2

-1.5

-1

-0.5

0

0 500 1000 1500

Elasped Time (days)

Ver

tical

Def

lect

ion

(%)


HD = 0.2208Ln(t) - 0.0713R2 = 0.5837(Test Pipe 6)

0

1

2

3

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 6)

150

VD = -0.0749Ln(t) - 0.0111R2 = 0.3948(Test Pipe 7)

-2

-1.5

-1

-0.5

0

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = -0.0292Ln(t) - 0.667R2 = 0.6628(Test Pipe 7)

-1

-0.9

-0.8

-0.7

-0.6

-0.5

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 7)

151

VD = -0.1098Ln(t) - 2.1595R2 = 0.392

(Test Pipe 8)

-4

-3

-2

-1

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = -0.1252Ln(t) + 0.7275R2 = 0.792

(Test Pipe 8)

-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 8)

152

VD = -0.0448Ln(t) - 1.8077R2 = 0.3725(Test Pipe 9)

-2.5

-2

-1.5

-1

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


HD = 0.0774Ln(t) + 0.6343R2 = 0.535

(Test Pipe 9)

0

0.5

1

1.5

2

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 9)

153

VD = -0.3577Ln(t) - 2.1372R2 = 0.6872

(Test Pipe 10)

-6

-5

-4

-3

-2

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)

Figure B.19: Regression Analysis of Vertical Deflection Changes over Time (Pipe

10)

HD = 0.158Ln(t) + 1.364R2 = 0.8285

(Test Pipe 10)

1

2

3

4

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 10)

154

VD = -0.1544Ln(t) - 2.5058R2 = 0.5191

(Test Pipe 11)

-5

-4

-3

-2

-1

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


11)

HD = 0.0732Ln(t) + 0.5626R2 = 0.8379

(Test Pipe 11)

0

0.5

1

1.5

2

0 500 1000 1500 2000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 11)

155

VD = -0.1264Ln(t) - 0.6281R2 = 0.8711

(Test Pipe 12)

-2

-1.5

-1

-0.5

0

0 500 1000 1500

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


12)

HD = -0.0068Ln(t) + 0.3967R2 = 0.0537

(Test Pipe 12)

0

0.5

1

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 12)

156

VD = -0.45Ln(t) + 0.9812R2 = 0.9503

(Test Pipe 13)

-2.5

-2

-1.5

-1

-0.5

0

0 200 400 600 800 1000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


13)

HD = 0.094Ln(t) - 0.5329R2 = 0.467

(Test Pipe 13)

-1

-0.5

0

0.5

1

0 200 400 600 800 1000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 13)

157

VD = -0.0683Ln(t) - 1.2488R2 = 0.1991

(Test Pipe 14)

-3

-2

-1

0

0 500 1000 1500

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


14)

HD = -0.015Ln(t) + 0.2424R2 = 0.1275

(Test Pipe 14)

0

0.5

1

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 14)

158

VD = -0.0956Ln(t) - 0.6932R2 = 0.4674

(Test Pipe 15)

-3

-2

-1

0

0 500 1000 1500

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


15)

HD = 0.0139Ln(t) - 0.2924R2 = 0.0565

(Test Pipe 15)

-1

-0.5

0

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 15)

159

VD = -0.421Ln(t) + 1.2724R2 = 0.9458

(Test Pipe 16)

-3

-2

-1

0

0 500 1000 1500 2000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


16)

HD = -0.0322Ln(t) - 0.7311R2 = 0.2475

(Test Pipe 16)

-2

-1.5

-1

-0.5

0

0 500 1000 1500 2000

Elapsed Time (%)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 16)

160

y = -0.2708Ln(x) - 4.0002R2 = 0.9105

(Test Pipe 17)

-6

-5.5

-5

-4.5

0 200 400 600 800 1000

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


17)

HD = -0.0193Ln(t) + 0.9039R2 = 0.2925

(Test Pipe 17)

0

0.5

1

0 200 400 600 800 1000

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 17)

161

VD = -0.0102Ln(t) + 0.138R2 = 0.0935

(Test Pipe 18)

0

0.5

1

0 500 1000 1500

Elapsed Time (days)

Ver

tical

Def

lect

ion

(%)


18)

HD = -0.056Ln(t) - 0.634R2 = 0.7502

(Test Pipe 18)

-2

-1.5

-1

-0.5

0

0 500 1000 1500

Elapsed Time (days)

Hor

iz. D

efle

ctio

n (%

)


(Pipe 18)

163

APPENDIX C:

EFFECT OF TEMPERATURE ON

SOIL PRESSURE READINGS

164

Figures C.1 through C.38 present the plots correlating the soil pressure measurements to

the temperature readings registered by the pressure cell. Tables C.1 and C.3 summarize

the results of the analysis.

y = 0.4718x + 7.8555R2 = 0.6519

0.00

10.00

20.00

30.00

5.00 10.00 15.00

Temperature @ Crown (deg. C)

Soi

l Pre

ssur

e @

Cro

wn

(psi

)

Figure C.1: Correlation Between Temperature and Soil Pressure at Crown (Pipe

1)

y = 0.1067x + 11.035R2 = 0.0398

0.00

10.00

20.00

30.00

5.00 10.00 15.00

Temperature @ Springline (deg. C)

Soi

l Pre

ssur

e @

Spr

ingl

ine

(psi

)

Figure C.2: Correlation Between Temperature and Soil Pressure at Springline (Pipe 1)

165

y = 0.3865x + 14.813R2 = 0.1595

0.00

10.00

20.00

30.00

5.00 10.00 15.00


Soi

l Pre

ssur

e @

Cro

wn

(psi

)

Figure C.3: Correlation Between Temperature and Soil Pressure at Crown (Pipe 2)

y = 0.572x + 44.513R2 = 0.0152

10.00

20.00

30.00

40.00

50.00

60.00

70.00

5.00 10.00 15.00

Temperature (deg. C)

Soi

l Pre

ssur

e (p

si)


166

y = 0.7691x + 29.239R2 = 0.0749

10.00

20.00

30.00

40.00

50.00

5.00 10.00 15.00

Temperature @ Invert (deg. C)

Soi

l Pre

ssur

e (p

si)

Figure C.5: Correlation Between Temperature and Soil Pressure at Invert (Pipe 2)

y = 1.0678x + 4.6815R2 = 0.676

0.00

10.00

20.00

30.00

5.00 7.00 9.00 11.00 13.00 15.00 17.00


Soi

l Pre

ssur

e (p

si)


167

y = 1.6029x + 2.3145R2 = 0.5033

0.00

10.00

20.00

30.00

40.00

5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.4041x + 8.3611R2 = 0.3043

0.00

10.00

20.00

30.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


168

y = 0.2666x + 7.369R2 = 0.1509

0.00

10.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.6091x + 18.538R2 = 0.5646

0.00

10.00

20.00

30.00

40.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


169

y = 0.8892x + 16.79R2 = 0.4798

0.00

10.00

20.00

30.00

40.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.5416x + 36.337R2 = 0.4642

20.00

30.00

40.00

50.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


170

y = 0.664x + 4.0722R2 = 0.749

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.0397x + 6.9531R2 = 0.0192

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


171

y = 0.0286x + 5.4858R2 = 0.0033

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.2967x + 11.291R2 = 0.3833

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


172

y = -0.0435x + 16.179R2 = 0.0043

5.00

10.00

15.00

20.00

25.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.26x + 10.244R2 = 0.0369

0.00

10.00

20.00

30.00

5.00 10.00 15.00

Temperature @ Invert (deg. C)

Soi

l Pre

ssur

e (p

si)

Figure C.18: Correlation Between Temperature and Soil Pressure at Invert (Pipe 8)

173

y = 0.2067x + 5.5447R2 = 0.3827

0.00

5.00

10.00

15.00

5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.1465x + 6.8935R2 = 0.14

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


174

y = 0.0876x + 8.1256R2 = 0.0787

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.0928x + 8.8229R2 = 0.066

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


175

y = 0.2428x + 9.0718R2 = 0.4405

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Prre

suse

(psi

)


y = 0.8311x + 66.196R2 = 0.2462

60.00

70.00

80.00

90.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


176

y = 0.2378x + 5.7381R2 = 0.3491

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.3453x + 5.7954R2 = 0.6829

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


177

y = 0.1517x + 7.2193R2 = 0.1469

0.00

5.00

10.00

15.00

20.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.0429x + 9.3666R2 = 0.0119

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


178

y = -0.0587x + 12.592R2 = 0.0168

0.00

5.00

10.00

15.00

20.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.2045x + 7.5392R2 = 0.0973

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


179

y = 0.1299x + 7.2278R2 = 0.1619

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.2412x + 6.1111R2 = 0.6718

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


180

y = 0.3029x + 6.9192R2 = 0.4278

0.00

5.00

10.00

15.00

20.00

5.00 10.00 15.00


Soi

l Pre

ssur

e (p

si)


y = 0.2483x + 12.768R2 = 0.6306

5.00

10.00

15.00

20.00

25.00

30.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


181

y = 0.1973x + 9.7966R2 = 0.2659

0.00

5.00

10.00

15.00

20.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.0904x + 16.12R2 = 0.039

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


182

y = 0.3183x + 3.374R2 = 0.6584

0.00

5.00

10.00

15.00

20.00

0.00 5.00 10.00 15.00 20.00


Soi

l Pre

ssur

e (p

si)


y = 0.2393x + 3.1442R2 = 0.627

0.00

5.00

10.00

0.00 5.00 10.00 15.00 20.00

Temparature @ Springline (deg. C)

Soi

l Pre

ssur

e (p

si)


183

Table C.1: Linear Regression Analysis for Vertical Pressure at Crown (a) PVC Pipes Under 20-ft (6.1-m) Embankment Fill

Pressure vs. Temp. Relation: Pipe Wall Type Diameter (in)

Backfill Material & RC Slope (psi/°C) R2

1 Sand; 96% 0.472 0.652 3

A Crushed Rock; 86% 1.068 0.676

4 Sand; 86% 0.404 0.304 6

B

30

Crushed Rock; 96% 0.809 0.727 (b) PVC Pipes Under 40-ft (12.2-m) Embankment Fill


Backfill Material & RC Slope R2

2 A 0.387 0.160 5 B

30

Crushed Rock; 96% 0.609 0.565

(c) HDPE Pipes Under 20-ft (6.1-m) Embankment Fill



7 Sand; 96% 0.040 0.019 9

C Crushed Rock; 86% 0.207 0.383

10 Sand; 86% 0.088 0.079 12

D

30

Crushed Rock; 96% 0.238 0.349 13 Sand; 90% 0.152 0.147 15

E 42 Crushed Rock; 90% 0.130 0.162

16 Crushed Rock; 90% 0.303 0.428 18

F 60 Sand; 96% 0.318 0.658

(d) HDPE Pipes Under 40-ft (12.2-m) Embankment Fill



8 C 30 Sand; 96% 0.297 0.383 11 D 42 Crushed Rock; 96% 0.243 0.441 14 E 30 Sand 96% - 0.059 0.017 17 F 60 Crushed Rock; 96% 0.197 0.266

184

Table C.2: Linear Regression Analysis for Lateral Pressure at Springline (a) PVC Pipes Under 20-ft (6.1-m) Embankment Fill



1 Sand; 96% 0.107 0.039 3

A Crushed Rock; 86% 1.603 0.503

4 Sand; 86% 0.267 0.151 6

B

30




2 A 0.572 0.015 5 B

30

Crushed Rock; 96% 0.889 0.480




7 Sand; 96% 0.029 0.003 9

C Crushed Rock; 86% 0.147 0.140

10 Sand; 86% 0.093 0.066 12

D

30


E 42 Crushed Rock; 90% 0.241 0.672

16 Crushed Rock; 90% 0.248 0.631 18

F 60 Sand; 96% 0.239 0.627




8 C 30 Sand; 96% - 0.044 0.004 11 D 42 Crushed Rock; 96% 0.831 0.246 14 E 30 Sand 96% 0.205 0.097 17 F 60 Crushed Rock; 96% 0.090 0.039

185

Table C.3: Linear Regression Analysis for Vertical Pressure at Invert (a) PVC Pipes Under 20-ft (6.1-m) Embankment Fill



2 A 30 Crushed Rock; 96% 0.769 0.075 (b) HDPE Pipes Under 40-ft (12.2-m) Embankment Fill



8 C 30 Sand; 96% 0.260 0.004

The results summarized in the above tables indicate that the seasonal fluctuations

of the soil pressure were more pronounced for the PVC pipes installed under 20-ft soil

cover than the HDPE pipes placed under the same soil cover height or PVC pipes under

40-ft soil cover. This trend may be somewhat surprising at first, considering the fact that

the coefficient of thermal expansion of HDPE is twice as large as that of PVC. However,

it starts to make sense realizing that the hoop stiffness of PVC is higher and that the

pipe’s exterior surface geometry in relationship to the gradation characteristics of the

backfill soil may be playing a role in controlling the magnitude of the thermally induced

soil pressure around the pipe circumference.

187

APPENDIX D:

EFFECT OF TEMPERATURE ON

PIPE DEFLECTIONS

188

In order to see if temperature has any influence on the pipe deflections, the temperature

registered by the pressure cells are plotted against the pipe deflections in Figures D.1

through D.36. Tables D.1 and D.2 summarize the results of the analysis.

y = 0.0173x + 0.3057R2 = 0.3226

y = -0.0231x - 0.7518R2 = 0.1317

-2

-1

0

1

2

5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD

Figure D.1: Correlation Between Temperature at Crown and Deflections (Pipe 1)

y = -0.0133x + 0.7375R2 = 0.0332

y = 0.0535x - 1.7155R2 = 0.1911

-2

-1

0

1

2

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD

Figure D.2: Correlation Between Temperature at Springline and Deflections (Pipe 1)

189

y = 0.0631x + 0.3605R2 = 0.1923

y = -0.0653x - 1.3577R2 = 0.1368

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns

VDHD


y = 0.0838x + 0.2886R2 = 0.1512

y = -0.0844x - 1.3454R2 = 0.1023

-5

0

5

8 10 12 14


Pip

e D

efle

ctio

ns (%

)

VDHD


190

y = 0.1074x + 0.7615R2 = 0.5583

y = -0.0695x - 1.5109R2 = 0.5182

-5

0

5

5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.1122x + 0.4178R2 = 0.4545

y = -0.075x - 1.1592R2 = 0.4491

-5

0

5

5 10 15 20

Temp. @ Springline (deg. C)

Pip

e D

efle

ctio

n (%

)

VDHD


191

y = 0.0028x + 0.8886R2 = 0.0024

y = -0.0175x - 1.5514R2 = 0.2801

-3

-2

-1

0

1

2

3

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.0055x + 0.8612R2 = 0.0108

y = -0.016x - 1.5604R2 = 0.2639

-3

-2

-1

0

1

2

3

5 10 15

Temperature at Springline (deg. C)

Pip

e D

efle

ctio

ns (%

)

VDHD


192

y = 0.1362x + 0.0715R2 = 0.3061

y = -0.1326x - 0.4112R2 = 0.2987

-5-4-3-2-1012345

5 10 15

Temp. @ Crown (Deg. C)

Pip

e Def

lect

ions

(%)

VDHD


y = -0.0795x - 0.7736R2 = 0.1257

y = 0.085x + 0.418R2 = 0.1294

-5-4-3-2-1012345

5 10 15

Temp. @ Springline (Deg. C)

Pip

e D

efle

ctio

ns (%

)

VDHD


193

y = 0.0553x + 0.556R2 = 0.2958

y = -0.0176x - 0.5543R2 = 0.1108

-3

-2

-1

0

1

2

3

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.0633x + 0.4683R2 = 0.2781

y = -0.019x - 0.5388R2 = 0.0929

-3

-2

-1

0

1

2

3

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


194

y = -0.0002x - 0.4296R2 = 3E-05

y = 0.0077x - 0.9303R2 = 0.3742

-2

-1.5

-1

-0.5

0

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.0091x - 0.9428R2 = 0.4394

y = 0.0004x - 0.4353R2 = 7E-05

-2

-1.5

-1

-0.5

0

5 10 15


Pipe

Def

lect

ions

(%)

VDHD


195

y = -0.0693x - 2.0201R2 = 0.3609

y = 0.0033x - 0.0831R2 = 0.0057

-4

-3

-2

-1

0

1

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.0017x - 0.066R2 = 0.0013

y = -0.0655x - 2.0514R2 = 0.2747

-4

-3

-2

-1

0

1

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


196

y = -0.025x - 1.7614R2 = 0.2541

y = 0.0141x + 0.919R2 = 0.0954

-5

0

5

5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0235x - 1.7812R2 = 0.1763

y = 0.0099x + 0.969R2 = 0.0366

-5

0

5

5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


197

y = -0.018x - 3.898R2 = 0.0156

y = 0.0254x + 1.9635R2 = 0.156

-10

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0006x - 4.0657R2 = 2E-05

y = 0.0141x + 2.0654R2 = 0.0714

-10

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


198

y = -0.0618x - 2.7006R2 = 0.3804

y = 0.0167x + 0.7947R2 = 0.3902

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0669x - 2.6302R2 = 0.3386

y = 0.018x + 0.7768R2 = 0.343

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


199

y = -0.0373x - 0.9382R2 = 0.3146

y = 0.0029x + 0.3281R2 = 0.0581

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0366x - 0.9401R2 = 0.1941

y = 0.0044x + 0.3118R2 = 0.0856

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


200

y = -0.0633x - 0.7746R2 = 0.4278

y = 0.0219x - 0.2425R2 = 0.4835

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0639x - 0.7281R2 = 0.2607

y = 0.0269x - 0.3063R2 = 0.4178

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


201

y = -0.0086x - 1.5568R2 = 0.0569

y = 0.003x + 0.1072R2 = 0.0227

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0065x - 1.5778R2 = 0.0296

y = 0.0038x + 0.0969R2 = 0.0346

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


202

y = -0.0082x - 1.1328R2 = 0.0258

y = 0.0115x - 0.3319R2 = 0.4042

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0043x - 1.1716R2 = 0.0062

y = 0.0108x - 0.3289R2 = 0.3177

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


203

y = -0.0836x - 0.3078R2 = 0.378 (for VD)

y = -0.0017x - 0.9043R2 = 0.0087 (for HD)

-5

0

5

5 10 15


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0659x - 0.507R2 = 0.2927 (for VD)

y = -0.0015x - 0.9065R2 = 0.0086 (for HD)

-5

0

5

5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


204

y = -0.004x + 0.8391R2 = 0.4274

y = -0.0403x - 5.0719R2 = 0.3643

-10

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = -0.0048x + 0.8461R2 = 0.4318

y = -0.0438x - 5.0469R2 = 0.3006

-10

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


205

y = -0.0004x + 0.0842R2 = 0.0024

y = -0.0116x - 0.8359R2 = 0.4767

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


y = 0.0002x + 0.0779R2 = 0.0006

y = -0.0103x - 0.8475R2 = 0.4094

-5

0

5

0 5 10 15 20


Pip

e D

efle

ctio

ns (%

)

VDHD


206

Table D.1: Linear Regression Analysis for Vertical Deflection (a) PVC Pipes Under 20-ft (6.1-m) Embankment Fill

V. Deflect vs. Temp. @ Crown: Pipe Wall Type Diameter (in)

Backfill Material & RC Slope (%/°C) R2

1 Sand; 96% -0.0231 0.132 3

A Crushed Rock; 86% -0.0695 0.518

4 Sand; 86% -0.0175 0.280 6

B

30

Crushed Rock; 96% -0.0176 0.111 (b) PVC Pipes Under 40-ft (12.2-m) Embankment Fill



2 A -0.0653 0.137 5 B

30

Crushed Rock; 96% -0.1326 0.299




7 Sand; 96% -0.0002 3E(-5) 9

C Crushed Rock; 86% -0.0250 0.254

10 Sand; 86% -0.0180 0.016 12

D

30

Crushed Rock; 96% -0.0373 0.315 13 Sand; 90% -0.0633 0.428 15

E 42 Crushed Rock; 90% -0.0082 0.026

16 Crushed Rock; 90% -0.0836 0.378 18

F 60 Sand; 96% -0.0004 0.002




8 C 30 Sand; 96% -0.0069 0.361 11 D 42 Crushed Rock; 96% -0.0618 0.380 14 E 30 Sand 96% -0.0086 0.057 17 F 60 Crushed Rock; 96% -0.0403 0.364

207

Table D.2: Linear Regression Analysis for Horizontal Deflection (a) PVC Pipes Under 20-ft (6.1-m) Embankment Fill

H. Deflect vs. Temp. @ Springline: Pipe Wall Type Diameter (in)


1 Sand; 96% -0.0133 0.033 3

A Crushed Rock; 86% 0.1122 0.455

4 Sand; 86% 0.0055 0.011 6

B

30




2 A 0.0838 0.151 5 B

30

Crushed Rock; 96% 0.0850 0.129




7 Sand; 96% 0.0091 0.439 9

C Crushed Rock; 86% 0.0099 0.037

10 Sand; 86% 0.0141 0.071 12

D

30


E 42 Crushed Rock; 90% 0.0108 0.318

16 Crushed Rock; 90% -0.0015 0.009 18

F 60 Sand; 96% -0.0103 0.410




8 C 30 Sand; 96% 0.0017 0.001 11 D 42 Crushed Rock; 96% 0.0180 0.343 14 E 30 Sand 96% 0.0038 0.035 17 F 60 Crushed Rock; 96% -0.0048 0.432

According to the regression analysis results summarized in the above tables, in

most of the cases the temperature increase translated into an increase in the horizontal

deflection and a decrease in the vertical deflection. When the pipe type, burial depth, and

the relative compaction are all fixed, the linear regression coefficient value tends to be

somewhat larger for the sand backfill than the crushed limestone backfill. For either type

208

of pipe material, the lower the relative compaction initially achieved on the backfill is,

the more the thermally induced deflections are. Also, it appears that the deeper the burial

depth is, the less the thermally induced deflections tend to be for the same change in the

temperature.

209

APPENDIX E:

THEORETICAL CONSIDERATIONS

210

A recent experimental study by Mwanang′onze and Moore (2003) showed that the

coefficient of thermal expansion (CTE) value of HDPE pipe material in the

circumferential direction is 1.23 x 10-4 °C. According to Koerner (1994), CTE values of

unplasticized PVC (u-PVC) material may be close to 6.00 x 10-5 °C.

E.1 Simple Analysis

A simple axis-symmetric analysis shows that maximum value of the soil pressure change

around the pipe due to temperature fluctuations of the pipe material is expressed:

Δp = ε Ms = (CTE)(ΔT)Ms (E.1) where Ms = constrained modulus of soil.

In most of the field cases involved in the current study, the temperature of the backfill

soil immediately against the pipe fluctuated between 6 and 14 °C (ΔT = 8 °C) annually

over the last five years. According to the report by Sargand et al. (2002), the one-

dimensional constrained modulus value may be anywhere between 1.5 and 3.5 ksi (10.3

and 24.1 MPa) for the sand backfill and between 3.1 and 5.0 ksi (21.4 and 34.5 MPa) for

the crushed limestone. Inputting these values into the above equation, the range of

thermally induced soil pressure is estimated to be 0.7 to 1.8 psi (4.8 to 12.4 kPa) for PVC

pipes embedded in the sand, 1.5 to 2.6 psi (10.3 to 17.9 kPa) for PVC pipes embedded in

the crushed limestone, 1.4 to 3.4 psi (9.7 to 23.4 kPa) for HDPE pipes embedded in the

sand, and 3.0 to 5.0 psi (20.7 to 34.5 kPa) for HDPE pipes embedded in the crushed

limestone. These estimates are for the cases in which the backfill soil is compacted

211

effectively against the pipe exterior surface. Obviously, the corrugations on some of the

HDPE pipes prevented efficient densification of the backfill soil against the pipe and

created a thin layer of loose soil around the pipe. Then, the thermally induced soil

pressure would be smaller than what Eq. E.1 estimates due to the presence of this thin

loose layer.

E.2 Analysis Based on Full-Field Elastic Solutions

According to the full-field elastic solutions for the buried pipe problem established by

Burns and Richard (1964), the pipe deflection (w), circumferential shortening (cs), and

radial pressure (σr) under the full-bond interface are expressed as:

( ) ( )[ ]θ2cos211 220 BAVFAUFMPRw

S

−−−−= (E.2)

⎥⎦

⎤⎢⎣

⎡⎟⎠⎞

⎜⎝⎛+−=

BCBA

MPRcs

S22 212 (E.3)

( ) ( )[ ]θσ 2cos4311 220 BACABPr −−−−= (E.4)

where P = pressure loading applied along boundaries; R = average pipe

radius; ( )CBUFUFA

/1

0 +−

= ; ( ) ( )( ) ( ) ( )CUFBVFCVFB

BUFBCVFUFCA+++++

+−−=

12/112/1

2 ;

( ){ }( ) ( ) ( )CUFBVFCVFB

BVFUFCBB+++++

−+=

12/112

2 ; B = 0.5(1 + K); C = 0.5(1 – K); K =

υs/(1 – υs2);

pp

s

AERBM

UF2

= ; pp

s

IERCM

VF3

3

= ; and Ep = E/(1 – υ2).

212

Similarly, the pipe deflection (w), circumferential shortening (cs), and radial pressure (σr)

are expressed as follows for the free-slip interface conditions:

( ) ( )[ ]θ2cos211 *2

*20 BAVFAUF

MPRw

S

−−−−= (E.5)

( )*2

*2 431

223 BAUF

BCVF

MPRcs

S

−+⎭⎬⎫

⎩⎨⎧

⎟⎠⎞

⎜⎝⎛+= (E.6)

( ) ( )[ ]θσ 2cos4311 *2

*20 BACABPr −+−−= (E.7)

where ( )( )BVF

BVFA/312/112*

2 +−+−

= and ( )BVFVFB

/31212*

2 +−−

= .

The circumferential extension (ce) due to uniform temperature increase is:

ce = 2CTE(ΔT)πR (E.8)

Let the circumferential extension and circumferential shortening cancel each other, so

that there will be no diameter changes:

ce = cs ( )( )

( )BCBAMTCTE

P s

/21 22 +−Δ

=π

for full-bond interface (E.9)

( )( )( ){ }( )*

2*2 431/5.03

4BAUFBCVF

MTCTEP s

−++Δ

=π

for free-slip interface

213

The increase in the radial pressure due to temperature change can be determined by

applying the above boundary pressure P to the radial pressure formulas given by Eqs. E.4

and E.7. At the crown and springline positions where the radial soil pressures were

measured, these formulae simplify themselves to:

Crown (θ = 90°):

( ) ( )[ ]220 4311 BACABPr −−+−=σ for full-bond interface (E.4.a)

( ) ( )[ ]*2

*20 4311 BACABPr −++−=σ for free-slip interface (E.7.a)

Springline (θ = 0°):

( ) ( )[ ]220 4311 BACABPr −−−−=σ for full-bond interface (E.4.b)

( ) ( )[ ]*2

*20 4311 BACABPr −+−−=σ for free-slip interface (E.7.b)

The analytical results are presented in Table E.1. For convenience, the same elastic

modulus value was assumed for all of the PVC pipes. Similarly, all of the HDPE pipes

shared the same elastic modulus value as well.

Table E.1: Results of Analysis Based on Elastic Solutions ΔP (psi) Test

Pipe Pipe

Material CTE (°C)

Range of * Temp. (°C)

ΔT (°C)

Ave. Ep (psi)

Ms (ksi) FB FS

1 PVC 6.0E-5 5.9 to 13.7 7.8 380,000 3.5 4.1 1.7 2 PVC 6.0E-5 7.0 to 13.5 6.5 380,000 5.4 5.0 2.1 3 PVC 6.0E-5 7.9 to 14.8 6.9 380,000 3.5 3.6 1.5 4 PVC 6.0E-5 5.5 to 13.8 8.3 380,000 1.6 2.3 0.9 5 PVC 6.0E-5 6.4 to 15.4 9.0 380,000 5.4 7.1 3.0 6 PVC 6.0E-5 7.4 to 14.9 7.5 380,000 3.7 4.3 1.7 7 HDPE 1.23E-4 5.9 to 13.9 8.0 39,000 3.5 5.7 3.5 8 HDPE 1.23E-4 6.6 to 13.8 7.2 39,000 4.5 6.2 4.0 9 HDPE 1.23E-4 7.7 to 14.8 7.1 39,000 3.5 5.0 3.1

214

Table E.1: Results of Analysis with Elastic Solutions (cont’d) 10 HDPE 1.23E-4 5.9 to 18.4 12.5 39,000 1.6 4.9 2.5 11 HDPE 1.23E-4 6.4 to 13.6 7.2 39,000 5.4 7.2 4.8 12 HDPE 1.23E-4 7.0 to 14.8 7.8 39,000 3.7 5.8 3.6 13 HDPE 1.23E-4 3.9 to 15.8 11.9 39,000 1.9 5.0 2.8 14 HDPE 1.23E-4 5.1 to 14.8 9.7 39,000 4.5 8.0 5.4 15 HDPE 1.23E-4 5.6 to 14.6 9.0 39,000 3.2 5.7 3.5 16 HDPE 1.23E-4 5.8 to 14.8 9.0 39,000 3.2 5.7 3.5 17 HDPE 1.23E-4 4.5 to 16.7 12.2 39,000 5.4 11.8 8.1 18 HDPE 1.23E-4 5.0 to 15.1 10.1 39,000 3.5 6.9 4.3

[Notes] * The temperature range is based on the temperature readings recorded by the soil pressure cells after the end of construction. FB = Full-Bond; and FS = Free-Slip.

Δσr (psi) @ Crown Δσr (psi) @ Springline Δσr (psi) in Field @ Test Pipe

Pipe Material Full-Bond Free-Slip Full-Bond Free-Slip Crown Springline

1 PVC 2.3 1.5 4.7 1.4 4.8 3.9 2 PVC 2.5 1.7 5.3 1.6 5.0 9.3 3 PVC 2.0 1.3 4.1 1.2 9.0 14.1 4 PVC 1.6 0.9 2.7 0.8 6.6 4.6 5 PVC 3.7 2.5 7.6 2.3 5.8 8.8 6 PVC 2.5 1.6 4.8 1.4 7.3 5.8 7 HDPE 0.9 1.2 2.8 1.1 2.4 4.1 8 HDPE 0.8 1.2 2.7 1.1 3.4 3.8 9 HDPE 0.8 1.1 2.5 1.0 2.5 2.4

10 HDPE 1.5 1.4 3.6 1.3 3.7 3.2 11 HDPE 0.8 1.2 2.8 1.1 3.0 7.6 12 HDPE 0.9 1.2 2.9 1.1 3.0 2.8 13 HDPE 1.1 1.2 3.1 1.2 4.9 5.0 14 HDPE 0.8 1.3 3.0 1.2 5.1 7.8 15 HDPE 0.8 1.1 2.7 1.1 2.8 2.4 16 HDPE 0.9 1.2 2.8 1.1 5.5 4.2 17 HDPE 1.0 1.8 4.1 1.7 5.3 9.5 18 HDPE 1.0 1.3 3.2 1.3 4.2 3.5

The thermally induced soil pressure was estimated to be somewhat larger for the

PVC pipes than for the HDPE pipes. This was because of the higher hoop stiffness

values possessed by the PVC pipes. For each pipe material type, the full-bond solution

produced higher radial pressure changes at the springline position than at the crown. The

free-slip solution produced slightly higher radial pressure changes at the crown than at

215

the springline. Examining the results summarized in Table E.1, it is noted here that the

thermally induced changes in the radial soil pressure given by the theoretical approach

based on the full-field elastic solutions are smaller than what were measured at the crown

position for all of the pipes. The theoretical approach (with full-bond interface) yielded

reasonable results for eight out of the eighteen cases for the radial pressure changes at the

springline position (which are in bold). For the remaining ten cases, the theoretical

values are less than the field measured pressure fluctuations.

Finally, the effect of moisture fluctuations within the embankment fill soil may

also be addressed using the elastic solutions. Let us assume that the soil moisture content

fluctuates by 5% within the top 5-ft zone of the embankment fill. The average moist unit

weight of the fill material was 130 pcf during construction. With the 5% increase in its

moisture content, the moist unit weight might have approached 136 pcf. Eqs. E.2, E.4,

E.5, and E.7 indicate that both soil pressure (σr) acting against buried pipe and the pipe

deflections (w) are directly proportional to the vertical pressure applied at the top

boundary located not too far away above the pipe. For the 20 ft soil cover, the 5%

increase in the moisture content within the upper 5 ft zone may increase the P value by

about 1.5%. For the 40 ft soil cover, the 5% increase in the moisture content within the

upper 5 ft zone may increase the P value by about 0.7%. These suggest that both the soil

pressure and pipe deflections should fluctuate by only 0.7 to 1.5% if the moisture

conditions change seasonally as assumed here. The actual soil pressure fluctuations were

much larger than the range predicted here, which implies that the temperature effect

might have had more dominating effect than the soil moisture effect had.

ORITE • 141 Stocker Center • Athens, Ohio 45701-2979 • 740-593-2476

Fax: 740-593-0625 • [email protected] • http://webce.ent.ohiou.edu/orite/

long-term monitoring of pipe under deep cover

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