3er simposio internacional de cimentaciones profundas 05-11-2015)

8/15/2019 3er Simposio Internacional de Cimentaciones Profundas 05-11-2015)

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Volume Prepared by ISSMGE Technical Committee - 214

Volumen preparado por el Comité Técnico TC-214 de la ISSMGE

For / para

3rd International Conference on Deep Foundations

Deep Foundations and Soil Improvement in Soft Soils3er Simposio Internacional de Cimentaciones Profundas

Cimentaciones Profundas y Mejoramiento Masivo en Suelos Blandos

November 11-12th, 2015, Mexico City

Edited by / Editado por Norma Patricia López Acosta

Technical Committee TC-214


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Copyright, México, 2015

Sociedad Mexicana de Ingeniería Geotécnica, A.C.Valle de Bravo No. 19 Col. Vergel de Coyoacan,14340 México, D.F., MÉXICOTel. +(52)(55)5677-37-30, Fax+(52)(55)5679-36-76Página web: www.smig.org.mxCorreo electrónico: [email protected]

Prohibida la reproducción parcial o total de esta publicación, por cualquier medio, sin la previaAutorización escrita de la Sociedad Mexicana de Ingeniería Geotécnica, A.C.Total or partial reproduction of this book by any medium requires prior written consent of theSociedad Mexicana de Ingeniería Geotécnica, A.C.

Las opiniones expresadas en este volumen son responsabilidad exclusiva de los autores.Opinions expressed in this volume are the sole responsibility of their authors.

Collaborators (Editing and Formatting)/ Colaboradores (Edición y Formato): A.R. Pineda Contreras,E. Martínez Hernández y A.L. Espinosa Santiago.

mailto:[email protected]:[email protected]:[email protected]:[email protected]


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SOCIEDAD MEXICANA DE INGENIERÍA GEOTÉCNICA A.C.

COUNCIL OF HONOR / CONSEJO DE HONOR

Leonardo Zeevaert Wiechers†

Raúl J. Marsal Córdoba†

Alfonso Rico Rodríguez†

Enrique Tamez GonzálezGuillermo Springall CaramEdmundo Moreno Gómez

Carlos Jesús Orozco y Orozco†

Luis Vieitez Utesa

Gabriel Moreno PeceroRaúl López Roldán

Raúl Flores BerronesLuis Miguel Aguirre Menchaca†

Gabriel Auvinet Guichard

Luis Bernardo Rodríguez GonzálezRaúl Vicente Orozco Santoyo

Alberto Jaime Paredes

Mario Jorge Orozco CruzJuan Jacobo Schmitter Martín del Campo

Héctor M. Valverde Landeros

CONSULTIVE COUNCIL / CONSEJO CONSULTIVO

José Francisco Fernández RomeroRigoberto Rivera Constantino

Walter Iván Paniagua ZavalaJuan de Dios Alemán Velásquez

David Yáñez Santillán

BOARD / MESA DIRECTIVA 2015-2016

Raúl Aguilar Becerril President

Norma Patricia López Acosta

Vice-President Carlos Roberto Torres Álvarez

Secretary Celestino Valle Molina

Treasurer María del Carmen Suarez Galán

Nilson Contreras PallaresMiguel Figueras Corte

Aristóteles Jaramillo RiveraTechnical Assistants


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ORGANIZING COMMITTEE / COMITÉ ORGANIZADOR

3rd International Conference on Deep Foundations / 3er Simposio Internacional de Cimentaciones Profundas

Walter I. Paniagua Zavala ISSMGE

Juan Paulín Aguirre ISSMGE

Norma Patricia López Acosta SMIG

Mary Ellen Large DFI

Theresa Engler DFI

Vernon Schaefer G-I


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2015

November 11-12th,

Mexico City

3rd International Conference on Deep FoundationsDeep Foundations and Soil Improvement in Soft Soils


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Foreword

On behalf of the Technical Committee TC-214 of the International Society for Soil Mechanics and

Geotechnical Engineering (ISSMGE), it is a privilege to present this volume for the 3rd International

Conference on Deep Foundations (Deep Foundations and Soil Improvement in Soft Soils), held in

Mexico City, November 11-12th, 2015.

This time, four organizations have joined efforts to produce it: the above mentioned TC-214

(Foundations Engineering for Difficult Soft Soil Conditions), the Mexican Society for Geotechnical

Engineering (SMIG, which hosts the TC-214), the Deep Foundations Institute (DFI), and the Geo-

Institute of ASCE. In two previous events, SMIG and DFI had collaborated in 2011 and 2013 to

organize the First and Second International Conference on Deep Foundations, with very good

acceptance in the geotechnical community.

The purpose of merging different entities is multiple: to foster collaboration between countries, to

continue the technological and scientific knowledge transference, and to promote different points ofview from geotechnical professionals, including academicians, consultants, contractors and equipment

manufacturers.

Therefore, the material presented hereby, includes a wide spectre of the deep foundations and soil

improvement current knowledge, with special emphasis in soft soils. Three main topics are

recognized: Deep foundations, Excavations, and Soil Improvement. From state of the art of

geotechnical research to case histories, the papers presented herein give a general -and present-

perspective on this matter.

My gratitude to all attendees, speakers, exhibitors and members of the Organizing Committee, for

their interest, collaboration and hard work in this event.

Walter I. Paniagua

TC-214, Chair

Pilotec, SA de CV


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Introduction

The interest for constructing high-rise buildings in urban zones and the necessity to build structures in

difficult subsoil conditions requires engineers to look for efficient solutions. Scenarios are challenging

the projected structures that are affected by significant natural forces, such as those imposed by wind,earthquakes or sea waves. The construction of deep foundations and the soil improvement works

have proved to be efficient alternatives to handle these situations.

In many cases, especially when loads and mechanical elements are of important magnitude, the design

of deep foundations is mandatory. For example deep foundations are employed when weak or

otherwise unsuitable soil exists near the subsurface and the vertical loads must be carried to depth

deposits. Deep foundations have other uses, for example they are used to resist scour, sustain axial

loading by side resistance in strata of granular soils or competent clay, allow above-water

construction, support lateral forces, improve the stability of slopes, reduce settlements and other

special purposes. The most used deep foundations are driven piles and drilled shafts.

In other cases, when the resistance or deformability conditions of soils are not allowable for the

project, the use of techniques for soil improvement are required. They help to reduce total or

differential settlements, increase axial and lateral bearing capacity and, in some cases, help to avoid an

undesirable soil behavior, such as liquefaction, swelling, among others.

The 3rd International Conference on Deep Foundations (3rd ICDF), held for the third time in Mexico

City, is a space to present recent experiences related to deep foundations and in this occasion it

includes the topic of massive improvement in soft soils. The aim of this conference is to promote the

most recent technical and scientific developments and to share experiences in the design and

construction of deep foundations and improvement techniques of soils.

The papers received for the 3rd ICDF include subjects such as cases history, foundations for high-rise

towers, geo-construction techniques, special deep foundations, cases of improvements on different

subsoils and deep excavations, among others. There is no doubt that the lectures on these topics will

also increase our knowledge of soil behavior.

My sincere acknowledgment to all authors for their invaluable contributions as well as to the

Organizing Committee for their efforts to achieve a successful Conference.

The Mexican Society for Geotechnical Engineering is proud to hold the 3rd ICDF on Mexico City

and will collaborate continuously with the Deep Foundations Institute, the Geo-Institute and the

International Society for Soil Mechanics and Geotechnical Engineering through its ISSMGE

Technical Committee TC-214, in order to promote the dissemination of the geotechnical knowledge.

Raúl Aguilar Becerril

Presidente SMIG – Mesa Directiva 2015-2016


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3rd International Conference on Deep FoundationsDeep Foundations and Soil Improvement in Soft Soils

SOCIEDAD MEXICANA DE INGENIERÍA GEOTÉCNICA A.C. xi

Technical Committee

TC-214

Contents

Foreword............................................................................................................................ vii

Introduction........................................................................................................................ ix

SESSION 1. DEEP FOUNDATIONS 1

Effects of varved deposit on driven piles at a LNG terminal site

Efectos de depósitos estratificados en pilotes hincados en el sitio de la terminal LNG

LIN Guoming, HUANG Yanbo & LIN Cheng .............................................................. 3Low noise and low vibration press-in piling method in soft soil in congested urban

areas

Método de piloteo de baja presión de vibración y bajo ruido en suelos blandos en áreas

urbanas congestionadas

TAKUMA Takefumi..................................................................................................... 11The use of displacement piling technology in soft soil conditions

El uso de tecnología de pilotes de desplazamiento en condiciones de suelo blando

MARINUCCI Antonio & CHIARABELLI Marco......................................................... 19Rescate de una cimentación de pilas con inclusiones rígidas

Pile foundation retrofit with rigid inclusions

SEGOVIA José, PANIAGUA Walter y LÓPEZ Germán............................................... 31Foundation design and construction for high-rise Towers in Mexico City

Diseño de la cimentación y construcción de Torres de gran altura en la Ciudad de México

DEMING Peter W., NIKOLAOU Sissy, POLETTO Raymond J. &TAMARO George J..................................................................................................... 39

Deep foundations in Mexico City soft soils

Cimentaciones profundas en suelos blandos de la Ciudad de México

AUVINET-GUICHARD Gabriel & RODRÍGUEZ-REBOLLEDO Juan-Félix.............. 51The use of micropiles technology in soft soil conditions

El uso de tecnología de micropilotes en condiciones de suelo blando

PAGLIACCI Federico................................................................................................. 67

Page


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Contents 3rd International Conference on Deep Foundations

Deep Foundations and Soil Improvement in Soft Soils

xii SOCIEDAD MEXICANA DE INGENIERÍA GEOTÉCNICA A.C.

Pore pressure build-up due to pile driving in clayey deposits

Desarrollo de presión de poro debido al hincado de pilotes en depósitos arcillosos

MENDOZA Manuel J., RUFIAR Miguel, IBARRA Enrique &

OROZCO Marcos........................................................................................................... 77Geotechnical design of the foundation for an office building located at the transition

zone

Diseño geotécnico de la cimentación para un edificio de oficinas localizado en la zona de

transición

ARENAS Fernando & CUEVAS Alberto......................................................................... 85

SESSION 2. EXCAVATIONS 91

A historic capitol and a deep excavation

Un capitolio histórico y una excavación profunda MASSOUDI Nasser & SLIWOSKI Richard .................................................................... 93

The support of a 25 m deep excavation in difficult ground conditions using Single

Bore Multiple Anchor technology

Soporte de una excavación de 25 m de profundidad en condiciones de terreno difícil

usando tecnología de anclaje múltiple con barreno único

MOTHERSILLE Devon & OKUMUSOGLU Bora......................................................... 97The use of MSE walls backfilled with Lightweight Cellular Concrete in soft ground

seismic areas

El uso de muros MSE rellenados con concreto celular ligero en áreas sísmicas de terrenos

blandos

PRADEL Daniel & TIWARI Binod ................................................................................. 107

SESSION 3. SOIL IMPROVEMENT 115

Soil improvement around the world – Applications and solution examples

Mejoramiento de suelos alrededor del mundo – Aplicaciones y ejemplos de solución

GERRESSEN F............................................................................................................... 117Principles and application of soil mixing for ground improvement

Principios y aplicación de la técnica soil mixing para mejoramiento de sueloWILK Charles M............................................................................................................. 123

Sustitución dinámica aplicada en turbas de la península de Yucatán

Dynamic replacement soil improvement technique applied in peaty soils in the peninsula

of Yucatan

CIRION ARANA Alfredo, CHATTE Rémi & PAULÍN AGUIRRE Juan......................... 127Transforming marginal land to support a world class development in Panama

Modificación de suelos marginales para apoyar proyectos de clase mundial en Panamá

LANGONI Gustavo & ARCHABAL Roger ..................................................................... 131

Page


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International Conference on Deep Foundations

Deep Foundations and Soil Improvement in Soft Soils

Session 1:

Deep foundations

3rd.

Technical Committee

TC-214


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Sociedad Mexicana de Ingeniería Geotécnica

Technical Committee

TC-214

3ER SIMPOSIO INTERNACIONAL DE CIMENTACIONES PROFUNDAS

Noviembre 11-12, 2015 – México, D. F.


Effects of varved deposit on driven piles at a LNG terminal site

Efectos de depósitos estratificados en pilotes hincados en el sitio de la terminal LNG

Guoming LIN1, Yanbo HUANG2, and Cheng LIN 3

1 Senior Consultant, Terracon, 2201 Rowland Avenue, Savannah, GA 31404; [email protected] Geotechnical Engineer, Terracon, 2201 Rowland Avenue, Savannah, GA 31404; [email protected] Geotechnical Engineer, Terracon, 2201 Rowland Avenue, Savannah, GA 31404; [email protected]

ABSTRACT: More than 6000 steel pipe piles are required for a proposed large LNG (Liquefied Natural Gas) Terminal

project. The regasification facility includes three 3.5 billion cubic feet (100 million cubic meters) double-wall storage

tanks for a daily send-out capacity of 1.2 billion cubic feet (33 million cubic meters) and a pier designed to berth ships

with a capacity of 200,000 cubic meters. The subsurface conditions at the tank locations were explored with a

combination of 12 soil test borings (STB), 34 cone penetration test (CPT) soundings and eight dilatometer test (DMT)

soundings. The geotechnical study also included field vane shear testing, pore pressure dissipation testing andlaboratory testing. The site subsurface conditions feature a layer of 90-foot thick very soft to stiff clayey silts with

interbedded thin sand seams (varved deposit). Characterization of this varved deposit layer, especially its shear strength

and preconsolidation history, is critical to the foundation design and construction for this project. However, the unique

structure of the clayey silts presents difficulties in defining some of its properties such as time rate of consolidation and

undrained shear strength. This paper presents the subsurface exploration program and the methods used to characterize

the clayey silts from the field and laboratory testing results. The preconsolidation history of this layer was evaluated using

several different approaches. This paper discusses the potential downdrag force and its implication in the pile design and

construction. A statistical procedure is developed to analyze axial pile capacities using SPT and CPT based methods and

pile capacities obtained from different methods are compared and discussed.

1 INTRODUCTION

1.1 Project information

The proposed LNG Terminal includes three 150,000cubic meter (944,000 barrel) double wall insulatedLNG storage tanks, process equipment consisting ofcompressors and vaporizer, buildings, pipelines,impoundment dikes, roads, and a parking lot. A jettywill be built for unloading LNG tankers and abreakwater may be built to provide a sheltered areafor the tanker. The tanks are designed to storeliquefied natural gas (LNG) at a pressure of 2.0 psigand a temperature of -270°F. The tanks will have anouter concrete wall (122 feet in inner radius) and aninner steel tank. The project will require a permitfrom the Federal Energy Regulatory Commission(FERC).

1.2 Site description

The site is located on the southeast bank of theDelaware River in Logan Township, GloucesterCounty, New Jersey. The property, approximately175 acres, is primarily an agricultural soybean field

with several gas and liquid petroleum pipe lines thattraverse the Delaware River and make landfall on thenorthwestern end of the property. The site isgenerally flat and had been used for disposing ofdredge spoil from the Delaware River before the1960s.

1.3 Geotechnical testing

The subsurface conditions of the site were exploredwith a combination of 12 soil test borings (STB), 34cone penetration test (CPT) soundings, and eightdilatometer test (DMT) soundings. Field vane sheartests were performed at three STB locations. Inconjunction with the CPT soundings, pore pressuredissipation tests were performed at various depthswithin four CPT locations were measured at thecenter of the three tanks. The laboratory testingprogram consisted of soil index testing, consolidationand triaxial shear strength testing, and chemicalanalyses.


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4 Effects of varved deposit on driven piles at an LNG terminal site


1.4 Subsurface Stratigraphy

The subsurface stratigraphy is generalized in thefollowing table.

Table 1. Generalized Subsurface Stratigraphy.Layer

No.Soil Type

AverageElevation(ft, NAVD)

H*(ft)

GeologicPeriod

1 Dredged Fill 7 to 3 4 RecentDredge Spoil

2 Sand/Gravelly Sand 3 to -3 6 Quaternary

3 Clayey Silt withInterbedded SandSeams

-3 to -93 90 Quaternary

4 Sand and Gravel -93 to -113 20 Quaternary

5 Residual Clayeysand

-113 to -148 35 Tertiary andCretaceous

6 Metamorphic Rock Below -148 --

*H is the average thickness of soil layer

Layer 3, termed varved deposit, has a thickness of85 to 95 feet and contains clayey silts with numerousinterbedded thin fine sand seams as shown in Figure1. Geologically, the soils were deposits of recent ageas a result of warmer temperatures and rise of oceanlevels after the Glacial Period. The fine grained soilsbecame fertile ground for vegetation which resultedin variable amounts of organics within this layer. Dueto its great thickness, the shear strength of this layercan greatly affect the pile capacities. Furthermore,potential downdrag force is a concern if the layer isunderconsolidated or will undergo additionalsettlements from the surface loads.

Figure 1. Photo of Clayey Silt with Interbedded Sand

Seams.

Samples taken from the SPT samplers and Shelbytubes allow visual observations of characteristics ofthe sand seams, such as the depth intervals, particle

sizes and thickness. The CPT soundings takereadings at 2-centimeter intervals, which is relativelyaccurate in determining the interfaces of the soilstrata. Figure 2 is a contour map showing the bottomelevation of the clayey silt layer varying approximatelyfrom -86 to -93 feet (NAVD) under Tank 1.

Figure 2. Bottom of the Varved Clay Layer.

2 CHARACTERIZATION OF THE VARVEDDEPOSIT (LAYER 3)

2.1 Soil index properties and classification

The Layer 3 soils are mostly classified as lowplasticity silts (ML) and high plasticity silts (MH) withoccasional classification of high plasticity clays (CH)or clayey sands (SC). Table 2 summarizes the soilindex and classification properties.

Table 2. Summary of Soil Index and ClassificationProperties.

# 200

Passing

(%)

Natural

Moisture

Content

(%)

Liquid

Limit

Plastic

Limit

Organic

Content

(%)

Range 50~98 20~90 27~94 12~50 1.7~7.1

Average 83 55 54 28 3.7

2.2 Consistency

SPT blow count, CPT tip resistance, and DMTmodulus were used to characterize the consistencyof the clayey silt. In general, the clayey silt exhibitedslightly increasing consistency with depth from soft atthe top to firm near the bottom.


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Figure 3. Unit Weight with Depth.

2.3 Unit weight

As shown in Figure 3, the unit weight derived fromDMT soundings agrees reasonably well with theresults of laboratory tests performed on Shelbytubes. The total unit weights were found to increaseslightly with depth in the clayey silt layer from 100 pcfat the top to 110 pcf at the bottom.

2.4 Undrained shear strength

The undrained shear strengths of the clayey siltswere obtained using three different methods:laboratory triaxial tests, field vane shear tests, andcorrelations from CPT data. Due to the effect of thinsand seams within the test specimens, almost allunconsolidated undrained (UU) triaxial tests resultedin a sloped failure envelope rather than a horizontalfailure envelope typical for normally consolidatedclays. The undrained shear strength was theninterpreted as the shear stress corresponding to theeffective in-situ overburden stress on the failureenvelope. The uncorrected undrained shear strengthobtained from field vane shear tests wasapproximately two times as large as the undrainedshear strength from the UU triaxial tests. Using theCorrection procedures of Bjerrum (1972) as revisedby Aas et al. (1986), the corrected vane shear

strength values agree reasonably well with thelaboratory test results, as shown in Figure 4. Thetrend of undrained shear strength increasing withdepth can be approximated exponentially or linearly.

In CPT soundings, the shear strength is related tothe cone tip resistance by a cone factor Nkt. An Nktvalue of 15 to 18 was obtained by matching theundrained shear strength derived from the CPT datato the best fitted curve from Figure 4. Previousstudies by others indicated the cone factor Nktgenerally ranges between 15 and 20 (ESOPT 1974and 1982, ISOPT 1988). Undrained shear strength

can be considered to increase from 400 psf at the topof clayey silt to 1100 psf at the bottom of the clayeysilt with an average value of 750 psf.

Figure 4. Undrained Shear Strength versus Depth(Exponential Regression).

2.5 Compressibility

Laboratory consolidation tests were performed usingboth conventional incremental loading procedures(ASTM D-2435) and constant strain rate (CSR)method (ASTM D-4186). The conventionalconsolidation tests yielded an average compressionindex (Cc) of 0.566 with an average initial void ratio(eo) of 1.535, which corresponded to an averagecompression ratio [Cc/(1+eo)]of 0.223. The CSR

consolidation tests measured an averagedcompression ratio of 0.218. Constrained modulus ofcompression (M), derived based on the empiricalcorrelations with DMT data (Schmertmann, 1988)and CPT data (Senneset et al., 1989 and Kulhawyand Mayne, 1990), varied approximately between 25and 60 tsf for the clayey silts. The constrainedmodulus derived from the three CSR consolidationtests averaged about 38 tsf.

2.6 Time rate of consolidation

The time rate of consolidation was characterizedusing laboratory consolidation tests and in-situ CPT

pore pressure dissipation tests. Theoretically, thedrainage path for the laboratory consolidation tests isin the vertical direction while the pore pressuredissipation tests measure pore pressure dissipationin the horizontal direction. The vertical coefficient ofconsolidation (CV) measured in the consolidationtest, varied between 0.1 and 0.5 ft2/day around thein-situ overburden stress. The coefficients ofconsolidation in the horizontal direction, Ch, werecalculated based on a method proposed by Mayne(2002). The Ch, values varied from 0.41 ft2/day to245 ft2/day. The large variation of the Ch values


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suggests that the rate of pore pressure dissipation(i.e. consolidation) is greatly affected by theinterbedded sand seams within the clayey silts

3 PRECONSOLIDATION HISTORY OF THEVARVED DEPOSIT (LAYER 3)

The consolidation history of the varved deposit, i.e.,whether the clayey silts are underconsolidated,normally consolidated or overconsolidated, isessential for the foundation design of this project.This condition will affect the magnitude of settlementof fills and shallow foundations and whether toconsider downdrag forces on deep foundations. Dueto the great thickness of the clayey silt layer andlarge number of piles to be used on this project, thisconsideration has substantial impact on the design ofthis project.

Geologically, the clayey silts (varved deposit) weredeposited along the shores of the Delaware Riverduring the late Pleistocene Period. The deposition ofthe layer was a long slow process taking place morethan ten thousand years ago. It is logical to assumethat the silts and clays had consolidated under theself-weight of the material. The dredged fills were lastdeposited at the site in the 1960s. From thegeotechnical standpoint, the clayey silts are morethan 80 feet in thickness, which would require a longtime to consolidate. However, the interbedded sandseams would function as horizontal drainage paths tofacilitate consolidation. As such, the key question is ifthe consolidation of the clayey silts has completedunder the weight of the dredged fill placed more than

30 years ago. Several different approaches weretaken in evaluating the preconsolidation history of theclayey silt layer at the site.

3.1 Atterberg limits

The relationship between the natural moisturecontents and Atterberg Limits can be used as anapproximate indication of soil’s preconsolidationhistory. Moisture contents that are well above theliquid limit at depths of tens of feet usually indicateunderconsolidation. Moisture contents near theplastic limit at shallow depths usually indicateoverconsolidation. A statistical analysis of thelaboratory test results performed on 30 Shelby tubesamples indicated an average natural moisturecontent of 55 percent and an average liquid limit of54 percent. The natural moisture contents are veryclose to the liquid limits. These properties lead to theconclusion that the soil is not significantlyoverconsolidated or underconsolidated.

3.2 Undrained shear strength

The undrained shear strengths generally increasewith depth (effective vertical stress). The best fit

curve using linear regression intercepts the strengthaxis at 75 psf (very small). The average strength gainis 15.9 psf per foot. Dividing the average strength bythe average effective vertical stress gives a c/p ratioof around 0.37, a reasonable value for a normallyconsolidated or slightly overconsolidated silt.

3.3 Overconsolidation ratio

In laboratory consolidation tests, smaller loadincrements were added in the vicinity of the existingoverburden pressure to fine-tune the compressioncurves for the determination of preconsolidationpressure. The preconsolidation stresses, determinedusing the Casagrande procedures, indicated OCRvalues ranging between 0.9 and 2.1 with an averageof 1.26. The OCR values were also derived from bothCPT and DMT using empirical correlations (Powelland Cuarterman, 1988; Kamei & Iwasaki, 1995). TheOCR of the clayey silts derived from DMT andobtained through consolidation tests fall mostlybetween 1 and 3, as shown in Figure 5. Therefore,the clayey silts are considered normally to slightlyover-consolidated based on the overconsolidationratio

Figure 5. OCR from DMT and Consolidation Test.

3.4 Consolidation theory

The Cv and Ch values obtained from the laboratoryconsolidation tests and derived from the field porepressure dissipation tests vary greatly with depthsand locations. The thickness of clay layer betweentwo drainage paths (sand seams) also vary greatly.Therefore, a conservative model was used to predictthe time required for the consolidation of the clayeysilts under the weight of the dredged fill. Using theTerzaghi’s one dimensional consolidation theory anda Cv of 0.01 ft2/day and a layer thickness of 10 feetbetween top and bottom drainage paths (both valuesare considered conservative based on the field and


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laboratory test results), a time of 5.8 years is requiredto reach 90 percent consolidation. Considering thedredged fill was last placed on site more than 30years ago, it is reasonable to believe that the clayeysilts had consolidated under the weight of thedredged fill.

4 PILE DESIGN CONSIDERATIONS

Steel pipe piles without concrete fill are consideredthe most suitable foundation system for this project(Yang et al., 2003). All piles are required to beembedded into the sand and gravel (Layer 4).Preliminary design performed by the design engineer(CB&l) requires an ultimate axial compressioncapacity of 200 tons and 280 tons for 18 and 22 inchdiameter piles, respectively.

4.1 Axial Pile capacities

The axial capacities will be largely dependent onthe adhesion between the pile and the clayey siltlayer (Layer 3). Several methods were used toestimate the axial capacities of driven piles understatic loads. These methods included calculatingadhesion and friction values between pile and soilbased on the soil strength from laboratory and fieldtesting, directly from the CPT results, and based onSPT blow counts using a computer program FHWADriven 1.2 (2001).

Cone penetration tests with pore pressuremeasurements (CPTu) are considered probably thebest in-situ test method for the design of axiallyloaded piles (Hannigan, et al. 1997). Variouscalculation methods based on CPT data werereviewed and compared, and two methods wereselected to estimate axial pile capacities for thisproject: the method developed by Bustamante andGiasenelli (1982), also called the LCPC method orthe French method and the method proposed byEslami and Fellenius (1997). Before the calculation,the depths associated with CPT data were adjustedto a ground surface at 6 feet NAVD.

To account for the variations of the soil conditionsat this site, a statistical analysis was performed byassuming pile capacities based on the CPT atdifferent soundings would have a normal distributionat the same depths. The procedure generated anupper bound, lower bound and an average pilecapacity at a given depth by eliminating the sampleswhich significantly deviate from the main group (morespecifically, values of probability density function lessthan 10 percent). Figures 6 and 7 present theultimate pile axial capacities for 18-inch steel pipepiles calculated using the two CPT methods and thestatistical procedure.

An average undrained shear strength of 750 psfwas derived from the laboratory and field tests, whichcorresponds to an adhesion of approximately 656 psf

based on the factor recommended by AmericanPetroleum Institute (API, 1993). For the clayey siltlayer defined in the Driven program, undrained shearstrength of 500 and 1000 psf, corresponding toadhesion values of 400 and 800 psf based onTomlinson’s (1980) method, were used as the lowerand upper bound values, respectively.

Figure 8 presents comparison of the ultimate axialcapacities using the two CPT based methods versusthe Driven program. For the CPT based methods, theaverage pile capacities obtained through thestatistical procedure are presented. It appeared theultimate axial pile capacities calculated from thethree different methods agree relatively well witheach other. Back-calculation based on the pilecapacity vs. depth curves indicated the averageadhesion values of the clayey silt were 500 and 750psf for the French Method and the Eslami & FelleniusMethod, respectively.

Figure 6. Ultimate Compression Capacities for 18-in SteelPipe Pile Using CPT methods by Eslamic & Felleniusmethod.

An ultimate compression capacity of 200 to 280tons was recommended for 18-inch and 22-inch ODpipe piles, respectively, after the piles are driven intothe sand and gravel layer. The pile length will varywith elevations of the top of the sand and gravel layeras well as the depth of penetration into this layer. Apile tip elevation between -95 and -108 feet NAVD

can be expected for the purpose of preliminarydesign and estimates.

0

20

40

60

80

100

1200 50 100 150 200 250 300 350 400 450 500

D e p t h

( f t )

Ultimate Compression Capacity (tons)

Eslamic & Fellenius (1997) Direct CPT Method,10 to 90% of Normal Distribution


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Figure 7. Ultimate Compression Capacities for 18-inchSteel Pipe Pile by French Method.

Figure 8. Comparison of Compression Capacities byDifferent Methods.

4.2 Downdrag Force

The preliminary grading plan shows the final grade inthe tank areas will be at or near the existing sitegrade. There will be minimal increase of stresses inthe soils from the fill and grading in the tank area.Based on analyses presented in the previous section,

it was concluded that the clayey silts are normallyconsolidated. No downdrag force was considered forthe piles underneath the tanks. However, there areuncertainties associated with potential secondaryconsolidation and long-term decomposition oforganic materials in the soils. The risk associatedwith the above uncertainties is considered relativelysmall. For the piles embedded in the sand and gravellayer (Layer 4), there is an extra 100 to 150 toncompression capacity available to offset this highlyunlikely but potential downdrag force. TheConstruction quality control program will require all

the piles to be embedded into the sand and gravellayer (Layer 4) even though the piles may achievethe required pile capacities with the pile tips abovethis layer.

5 SUMMARY AND CONCLUSIONS

1. The subsurface conditions for the proposed BPCrown Landing LNG terminal site were explored byusing a combination of 12 soil test borings, 34 conepenetration test soundings and eight dilatometersoundings. The site features a thick clayey silt layerwith interbedded fine sand seams. The strength andcompressibility characteristics of this clayey silt layerhave a major impact on the costs and safety of thepile foundation. The soil properties were tested usinga series of field vane shear tests, pore pressuredissipation tests and laboratory tests.

2. The combined use of SPT, CPT and DMTsoundings was a well thought-out choice forsubsurface exploration. The samples from the SPTsamplers and Shelby tubes allowed the engineers toclosely examine the characteristics of theinterbedded layers, such as the depth intervals,thickness and particle sizes of the sand seams. CPTsoundings provided more accurate determination ofthe depth of soil interface and continuous data forderiving other engineering properties and subsequentpile capacity calculations.

3. The undrained shear strength of the clayey siltswas determined using three different methods: field

vane shear tests, laboratory triaxial tests andempirical correlations from the CPT soundings. Theresults from different methods agree reasonably wellafter proper corrections.

4. The consolidation history of the clayey silts wasanalyzed qualitatively based on the geological andgeotechnical considerations and quantitatively usinglaboratory and field test results. The analysesconsistently indicate that the clayey silts are normallyconsolidated or slightly overconsolidated. Nodowndrag force was considered necessary for pilessupporting the tanks, where no stress increase fromfill or grading is anticipated.

5. Axial pile capacities were calculated using threedifferent methods: based on adhesion and frictionvalues of the soils, directly calculated from the CPTdata and SPT blow count values. Results from thesemethods were evaluated and compared. Conepenetration test data was considered the bestmethod in calculating pile capacities. A statisticalanalysis procedure was developed to account for thevariations of the soil conditions to present the pilecapacities in upper and lower bounds.


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6 ACKNOWLEDGEMENTS

The authors would like to acknowledge the followingorganizations and individuals for their help andsupport for this project: BP and Mr. Junius Allen,CB&I and Messrs Greg Bertha and Donald Barrs, Dr.Felix Yokel, Site Blauvelt Engineers, GeotestingExpress, and many current and formerTerracon/WPC colleagues Messrs. William Wright,Wu Yang, Edward Hajduk, Jian Fang, ThomasCasey, William Anderson and Donovan Ledford.

REFERENCES

Aas, G., Lacasse, S., Lunne, T., & Hoeg, K. (1986).“Use of In-situ Tests for Foundation Design onClay”, Publikasjon-Norges Geotekniske Institutt ,(166): 1-15.

American Society for Testing and Materials (2004).Standard Test Methods for One-Dimensional

Consolidation Properties of Soils UsingIncremental Loading , ASTM D-2435.

American Society for Testing and Materials (2006).Standard Test Method for One-DimensionalConsolidation Properties of Saturated CohesiveSoils Using Controlled-Strain Loading , ASTM D-4186.

API (1993). “Recommended Practice for Planning,Designing and Constructing Fixed OffshorePlatforms – Working Stress Design”, 20th Edition, American Petroleum Institute, Washington, DC.

Bjerrum, L. (1972). “Embankments on Soft Ground”, Proceedings of Performance of earth and earth-supported structures, ASCE. 1-54.

Bustamante, M., & Gianeselli, L. (1982). “PileBearing Capacity Prediction by Means of StaticPenetrometer CPT”, Proceedings of the SecondEuropean Symposium on Penetration Testing .493-500.

Eslami, A., & Fellenius, B. H. (1997). “Pile Capacityby Direct CPT and CPTu Methods Applied to 102Case Histories”, Canadian Geotechnical Journal ,Vol.34(6): 886-904.

Federal Highway Administration’s Driven 1.2computer program (2001). Blue-Six Software, Inc.

Hannigan, P. J., Goble, G. G., Thendean, G., Likins,G. E., & Rausche, F. (1997). “Design and

Construction of Driven Pile Foundations-Volume I& II”, FHWA-HI-97-014, Washington, D.C.Kamey, T. & Iwasaki, K. (1995). “Evaluation of

Undrained Shear Strength of Cohesive Soils Usinga Flat Dilatometer ”, Soils and Foundations, Vol35(2): 111-116.

Mayne, P. W. (2002). “Equivalent CPT Method forCalculating Shallow Foundation Settlements in thePiedmont Residual Soils Based on the DMTConstrained Modulus Approach” from http://www. geosystems.ce.gatech.edu/~geosys/.

Powell, J. J. M., & Quarterman, R. S. T. (1988). “TheInterpretation of Cone Penetration Tests in Clays,with Particular Reference to Rate Effects”, Penetration Testing , Balkema, Rotterdam, TheNetherlands, Vol. 2: 903-909.

Tomlinson, M. J. (1980). Foundation Design andConstruction, Pitman, London, UK

Yang, W., Fang, J., and Lin, G.M. (2003). WPC ’sGeotechnical Report Liberty LNG Project .Savannah, Georgia:


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Technical Committee

TC-214

3ER SIMPOSIO INTERNACIONAL DE CIMENTACIONES PROFUNDAS



Low noise and low vibration press-in piling method in soft soil in congestedurban areas

Método de piloteo de baja presión de vibración y bajo ruido en suelos blandos en áreas urbanas

congestionadas

Takefumi TAKUMA1

1Giken America Corp.

ABSTRACT: Pile driving causes ground vibrations and noise by pile driving machines used duringconstruction. Conventional pile driving has all but disappeared from urban construction because of theemissions of deafening noise and earth shattering vibrations. The “Press-in Piling Method” was developed tosolve most of the problems associated with pile driving in urban construction. This innovative piling technique

allows sheet piles and other types of prefabricated piles or panels to be hydraulically pressed into the groundusing the reaction force generated by the previously installed piles’ surface friction with soil and the system’sown weight. The Press-in pile driving machine ‘walks’ on top of the pile wall, gripping on previously installedpiles while installing the next pile immediately adjacent to the one just installed. While the method is highlysuited for soft ground, the system can also efficiently deal with hard soil, such as dense sand, stiff clay,gravels, cobbles, boulders and soft rock with attachments without another set of large equipment for pre-drilling. Some of the urban projects require pile driving in low head room or with very small clearance fromexisting structures. In other cases, the pile driving may have to be conducted without an access road to thepiling location. This paper presents as to how the Press-in Piling Technology can effectively mitigate thenegative environmental impacts associated with pile driving on urban infrastructure projects along with casestudies in Japan, U.S.A. and Mexico.

1 INTRODUCTION

The Press-in Piling Method was invented out of purenecessity back in 1975 in Japan, where very manyinfrastructure projects were simultaneously builtnationwide due to the country’s rapid economicexpansion as well as the government’s policy at thattime. A sheet pile driving project in a regional city ofKochi, some 500 kilometers west of Tokyo, wasforced to shut down due to a noise and vibrationcomplaint filed by a local resident who lived rightnext to the project. He had to rest during the daytimedue to his night time work. This incident prompted Akio Kitamura, who was the president of the localfoundation contractor involved, to start thinkingabout an alternative pile driving method which wouldnot generate noise or vibration. By collaboration witha local inventor who was dubbed “Edison of Kochi”,he built the first Press-in piling machine. Althoughthe original purpose for creating the pile driver wasto utilize it for his company’s sheet pile drivingprojects, foundation contractors in other regions ofthe country, who were also looking for a low noiseand low vibration pile driving method, started to ask

about the equipment. That was the beginning of thesuccess story of the Press-in Piling Method. By now,it has been widely used not only in Japan but also inmany parts of Asia, Europe and North America,providing environmentally-friendly solutions tonumerous foundation projects.

2 HOW DOES THE PRESS-IN PILING WORK?

The Press-in Piling Method typically utilizes reactionforce derived from a few previously installed piles tohydraulically push the next pile into ground (see

Figure 1). The Press-in piling equipment of this typegrips the top of already-driven piles to drive the newone and moves forward or backward on its own(See Figure 2). Due to the fact that this method isnot using vibrating or purcussive force to drive thepiles, it is regarded as a very environmentally-friedlypiling method.


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12 Low noise and low vibration press-in piling method in soft soil in congested urban areas


Figure 1. Principle of the Press-in Piling Method.

Its advantages are;

Low noise and practically vibration free. The equipment size is relatively small and its

clamping points on the pile are much lowerthan those of other piling methods. Thisenables the equipment to work in physicallytight working conditions, horizontally and

vertically. With attachments it can effectively drive piles

into hard soil. It can achieve much more accurate pile

installation thanks to a combination of thebetter control of the pile and the lowerclamping points compared to other pilingmethods.

Figure 2. Sequence of the Press-in Pile Driving.

3 PRESS-IN PILE DRIVING IN HARD SOIL

3.1 Water Jetting

Dense sand, stiff clay, gravel, cobbles and boulders

are difficult to drive piles into. In some cases,limestone, mudstone and weathered rock layersmay exist in pile lines. The high pressure water jetand crush auger attachments as part of the Press-inpiling technology are very useful tools to drive piles

into some of these hard soil. The high pressurewater jetting will be quite effective in dense sand andsilt layers. A small nozzle attached to the toe of eachpile blasts out a small diameter of high pressurewater to create a pilot hole in a hard soil, loosen itand lubricate the pile surface, reducing pile’s skin

friction. See Figure 3.


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TAKUMA T. 13


Figure 3. Press-in Piling with Integrated High Pressure Water Jetting for Dense Sand and Silt.

3.2 Crush Auger Attachment

The integrated auger, which simultaneously drillsinto hard soil as the pile is pressed in, allows the pileto be advanced by loosening, crushing and partially

removing the hard soil to accomplish the smooth piledriving. Figure 4 shows how the auger systemworks.

Figure 4. Press-in Piling with Integrated Crush Auger Attachment for Hard Soil.


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4 NON-STAGING PRESS-IN PILING FORPROJECTS WITH LIMITED ACCESS

The Press-in pile driving can be done by having allthe necessary equipment moving on top of already-driven piles. In other words, a line of driven piles canbe used as construction road by the Non-stagingPress-in Piling Method. Pile Runner transports thepiles from a faraway access point to the pile driver.

Clamp Crane picks up the pile from Pile Runner andpitches it to the pile driver. See Figure 5. Themethod is highly useful for projects that have limitedaccess, such as those above shallow or deep water,ones on a sloped embankment without the need forstaging or dense jungle without any constructionroad.

Figure 5. Non-staging Press-in Piling Method with Clamp Crane and Pile Runner.

5 CASE STUDIES

5.1 Myoshoji River Restoration Project (Gekitoku-1Section), Tokyo, Japan

Myoshoji River is one of Kanda River’s tributarieslocated approximtely 15 km northwest of downtownTokyo. Although only 9.7 km long and its watershedbeing relatively small, the river runs through denselypopulated residential and commercial areas of thecity. Very heavy rainfall (263 mm) on one Septemberevening in 2005 flooded more than 3,300 units ofbuildings in the area. To reduce such flooding in thefuture, this project was to widen the river to increasethe drainage capacity and to reduce the flood risk byinstalling 634 of 1,000 mm diameter tubular pilesinto the existing concrete retainig walls. The piledepth varied from 11 to 22 m. Rotary Press-in Pilingequipment was utilized to effectively drive the pilesinto the concrete retaining walls without removingthem. Each pile had cutter bits welded at the toe ofthe pile to facilitate the cutting operations. Due to theroads on both sides of the river being quite narrow

for site access and also to the fact that they had tobe kept open for the local traffic almost all the time,the Non-staging Press-in Piling Method wasadopted. The tube piles were delivered to theproject’s material handling point by a flat bed truckand tranferred to Pile Runner that subsequentlytraveled on the rail placed on the pile top to ClampCrane’s pick-up point without blocking the roadtraffic.

Figure 6 shows the project’s sectional view andFigure 7 shows site’s soil conditions containingdense sand, sandy gravel and consolidated siltlayers with SPT values at or higher than 50 at 8 mand continuously beyond 12 m below ground. TheRotary Press-in Piling equipment used a smallquantity of water as “lubricant” for efficient rotarycutting operations. Figure 8 shows the Rotary PileDriver at work just in front of a local clinic.


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TAKUMA T. 15


Figure 6. Sectional View of the Project.

Figure 7. Soil Conditions.

Figure 8. Pile Driving in Densely-populated Area.

5.2 Sandalwood Canal Improvement Project(Hodges Bl. from Beach Bl. to Atlantic Bl., ProjectNo. P-80-01) in Jacksonville, Florida, U.S.A.

This project was to repair the damaged earthenlevees by an earlier flooding as well as to increasethe drainage capacity of an existing canal bywidening/deepening with sheet piles driven into thelevees running through a densely populated area ofthe City of Jacksonville, Florida. In order to minimize

noise/vibration and also to reduce in-streamexposure of the equipment during construction, twounits of the Press-in pile drivers were used and thework was done during the dry season of winter. Thewidths of levee shoulders were relatively narrow(approximately 3 m, see Figure 9) for a truck craneto maneuver through, so a 10 ton capacity ClampCrane was used for hoisting sheet piles to the piledrivers. The soil conditions were primarily sandy withthe SPT values of between 10 and 45 as shown inFigure 10. The noise and vibration during the sheetpile driving were limited by the specifications in thefollowing manner.

“The hydraulic press-in equipment shall not

produce more than 70dB of noise, at a distance of25 feet from the equipment, while in operation. Itshall not produce any measurable vibration at theground surface, at a distance of 25 feet from theequipment, while in operation.”

Approximately 950 pairs of 7.0 m to 9.0 m long Z-shaped PZC18 type sheet piles were driven withoutcausing damages to the nearby homes. Figures 11and 12 show the jobsite before and during the sheetpile driving. The channel was sandwiched by rows ofhouses.


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Figure 9. Typical Cross Section.

Figure 10. Soil Conditions.

Figure 11. Sandalwood Canal After Vegetation Removal.


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TAKUMA T. 17


Figure 12. Two Units of Press-in Pile Drivers With Clamp Crane.

5.3 Foundation Reinforcement Work of San Juande Ulua Fortress, Veracruz, Mexico

The 16th century fortress’ foundation needed to berehabilitated and also protected to allow nearbycanal’s widening construction. To protect andreinforce the foundation, sheet piles were driven toform permanent retaining walls outside theperimeter of the fortress standing in sea water.Vibration from pile driving had to be minimized by

any means not to damage this invaluable historicallandmark. The agency in charge decided to adoptthe Press-in Piling Method to achieve this goal.Sheet pile alignments were on the west, south andsoutheast sides of the fortress as shown on Figure13.

Figure 13. Plan View of the Sheet Pile Wall.

Although the water depth was relatively shallow (3to 4 meters) and the soil is generally soft, there weresome harder layers due to dense sand mixed withshells as seen on Figure 14. The high pressurewater jet attachment was employed to effectively

deal with the harder layer in order to drive 18 meterlong U-shaped LX32 sheet piles.

Figure 14. Boring Data.

Sheet piles were driven right against the fortress’foundation on east and west sides. There was oneY-shaped connecting point with four sharp anglecorners of sheet pile walls. A barge-mounted cranewas used to pitch the sheet piles to the Press-in piledriver working on top of the sheets as shown onFigures 15 and 16.

Sheet Pile Line

San Juan de UluaFortress


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Figure 15. Section View of Sheet Pile Driving Work.

Figure 16. Profile of Sheet Pile Driving Work.

The sheet piles were driven accurately withoutcausing damage to the foundation or the fortress’structure. The operator was operating the pile driveron its own staging affixed to the machine. SeeFigure 17.

Figure 17. Sheet Pile Driving at Southwest Corner of theFortress.

6 CONCLUSION

Conventional pile driving methods not only causehated noise and vibration but also are not useableon many projects in congested and denselypopulated cities due to various local conditions. Onthe other hand, the Press-in Piling Method canachieve the project’s goal in harmony with suchurban environment. With attachments and auxiliarysystems, it has wide range of applications in highlycongested conditions. With ever growing population,the author believes that major cities in the worldincluding Mexico City and other populous cities inthe country will be greatly benefitted by adoption ofthis method. It has shown the ability to preserve thenation’s historical landmark in Veracruz.

REFERECES

White, D., Finlay, T., Bolton, M., and Bearss, G.

(2002),“Press-in Piling: Ground Vibration and NoiseDuring Piling Installation”, Proceedings of the International Deep FoundationCongress, ASCE Special Publication 116

Motoyama M., Goh, T. and Yamamoto, M. (2005)“Silent Piling Technology and Its Application inHong Kong”, Proceedings of the 2005 conferenceof the Hong Kong Branch of the CharteredInstitution of Highways and Transportation


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Sociedad Mexicana de Ingeniería Geotécnica 3ER SIMPOSIO INTERNACIONAL DE CIMENTACIONES PROFUNDAS



Technical Committee

TC-214

The use of displacement piling technology in soft soil conditions

El uso de tecnología de pilotes de desplazamiento en condiciones de suelo blando

Antonio MARINUCCI, PhD MBA PE1, & Marco CHIARABELLI1

1Soilmec North America, Houston, Texas, USA

ABSTRACT: Displacement piles are cast-in-pace, reinforced concrete piles that are formed with little or no soil removal,

where the soil is displaced radially into the soil by the drilling tool. This piling technique is applicable in soft-to-firm ground

conditions – in loose to medium dense sands and in cohesive soils where the undrained shear strength is less than about

100 kPa (2,000 psf). There are many benefits to the use of displacement piles, including low vibrations during pile

construction, minimal amount of soil removal, no need for stabilizing fluids (slurry), and improvement of the load resistance

especially in side friction. The benefits of displacement piling make this technology ideal in contaminated and/or urban

environments. This paper provides an overview of the various types of displacement piles that have been used, applicability

of the technology, and general requirements for types of equipment and tooling needed. In addition, practical examples of

the technology and recent advancements to displacement piling tooling will be presented as mini case histories.

.

1 OVERVIEW

Drilled displacement piles (DDP) refers to aspecialized technology in which a bored pile isconstructed using a process in which (1) a speciallydesigned tool is advanced into the ground using bothrotation and downward thrust (“crowd force”) todisplace the in situ soil radially outward into thesurrounding formation, and (2) concrete is injectedand steel reinforcement (if required) is inserted to fillthe created hole and provide structural stiffness. Akey benefit of DDP is the minimal amount of drill spoilsgenerated, which provides a cost effective andpractical solution for sites with contaminated soils(e.g., typically found at landfills, brownfield sites, andindustrial facilities). In addition to the reducedenvironmental impact, other advantages of DDP suchas proven reliability, relatively rapid construction, highdaily production, minimal noise associated with DDP,and minimal ground vibrations have contributed to theincreased use of the technique especially forconstruction in urban areas, in congested spaces, andin close proximity to existing structures.

DDP has been used as structural foundationelements (e.g., support column loading) and forground improvement (e.g., column-supportedembankments) on both commercial and public worktype projects. The maximum diameter and depth thatcan be achieved are directly related to the capabilityof the drill rig used to construct the DDP. As reportedin the literature, displacement piles with diametersranging from about 300 to 800 mm (12- to 32-inches)and to a maximum depth of approximately 35 m (115ft).

1.1 Description and Classification

The myriad types of bored piles are typically classifiedaccording to the qualitative amount of disturbanceresulting from the piles’ construction, which can rangefrom non-displacement type to a complete or fulldisplacement type of pile. Drilled shafts fall under thenon-displacement type of piling, and continuous flight

auger (CFA) piles can be categorized under eithernon-displacement or partial displacement typedepending on whether (a) the concrete/grout isinjected under pressure, and (b) the ratio of the outerdiameter of the hollow drill stem to the diameter of theborehole is greater than about 50-60%, in which casea greater amount of soil will be displaced radially andcompacted into the borehole wall. That is, a narrowerhollow stem will result in minimal-to-partialdisplacement of the soil, while a wider hollow stem willresult in a greater amount of soil being displaced intothe surrounding soil during drilling.

DDP can be listed under either partial displacementor full displacement type according to the installationmethod and/or the type/shape of tooling used tocreate the pile, which can be grouped as essentiallycylindrical shaped (Figure 1a) or screw shaped(Figure 1b).


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20 The use of displacement piling technology in soft soil conditions


(a) (b)Figure 1. Schematic of (a) cylindrical shaped and (b) screwshaped displacement piles.

A schematic of a representative displacement toolis shown in Figure 2, which highlights many of the

common components found on modern DDP tools. Ingeneral, modern displacement tools will contain thefollowing common elements (Figure 2): (1)displacement body, which is an enlarged section nearthe bottom of the drill string that facilitates soilmovement radially outward, thereby displacing it intothe surrounding soil, (2) a drilling tip attached to thebottom of the drill string that is used to loosen the soilduring the advancement of the tool (if a re-usabledrilling tip is used, a pivoting gate located near thebottom of the tool or drill string is utilized for theinjection of the concrete or grout; otherwise, with asacrificial drilling tip, the concrete or grout is injectedthrough the bottom of the drill string), (3) a hollow stemdrill string with a diameter smaller than or equal to thediameter of the displacement body, (4) a lower augersegment with partial flights that moves the soil upwardtoward the displacement body, and (5) an upper augersegment with partial flights that moves the soildownward toward the displacement body.

Figure 2. Schematic of a representative DDP tooldelineating many of the common components found onmost modern DDP tools (DeWaal displacement pile toolshown; modified from Basu et al, 2010).

1.2 Benefits provided by Displacement Piles

Various practitioners (Basu et al, 2010; Paniagua,

2006; Baxter et al, 2006; Bottiau, 2006; Brown, 2012;

NeSmith, 2004; Pagliacci and Chiarabelli, 2015; etc.)

have extolled the benefits realized through the use of

displacement piles, which include the following:

• Environmentally friendly because minimal amountof drill spoils produced return to ground surface,thereby lowering both the risks associated withtransport of spoils (especially contaminated material)and the cost of disposal;• Minimal vibration induced during the construction ofthe displacement pile because the rotarydrilling technique does not induce large vibrations intothe soil;• Even in loose soils, the borehole can be formedwithout need of steel casing and/or slurry;• Cleanness of the working platform, lowering the

risk to injury of onsite personnel;• Compared with non-displacement bored piletechniques, the concrete overbreak is significantlylower; and• Compared to non-displacement bored piletechniques, higher unit side friction and end bearingresistance can be achieved through the compaction ofthe surrounding soil, which results in a lower cost (perton of load).

2 INSTALLATION-INDUCED CHANGES

During the construction, the soil surrounding the DDPwill undergo changes to its stress state (e.g., changein void ratio) as a function of the soil type, originalstress state and consistency, shape of the tool, andinstallation method. The changes are directly causedby the loading imposed on the soil by the tool fromboth radial compactive/torsional stresses and verticalshearing stresses during the advancement andextraction of the tool. Ultimately, the groundimprovement induced by the installation processresults in larger unit values of side shear.Consequently, the load-displacement response of adisplacement pile is comparatively stiffer than that ofa similarly sized non-displacement pile; therefore,compared with similarly sized non-displacement piles,

DDPs will be able to achieve a given load resistanceat a shorter length.In loose to medium-dense cohesionless soils, the

compactive effort of the tool produces greater radialdisplacement and results in a decrease of the voidratio (higher relative density than initial) relativelysoon after construction is completed. Brown (2005)reported that DDPs “increase the horizontal stress inthe ground and densify sandy soils around the pileduring installation…[achieving] a measure of groundimprovement around the pile.” For soft to stiff(displaceable) cohesive soils, the soil will be deformed


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MARINUCCI A. et al . 21


plastically, may require some time to realize theincrease in shear strength as the soil undergoesconsolidation within the affected zone. In sensitivesoils, the disturbance caused by the displacement toolduring advancement and extraction could result inremolding and formation of residual shear planes.

In partially saturated and fully saturated soils, theadvancement and extraction of the displacement toolmay generate excess pore water pressures in the soilsurrounding the pile. For cohesionless soils withminor fines content (15%) and for cohesive soils, however, thedissipation of the induced excess pore waterpressures will require time to dissipate, which willdepend on the length of the drainage path. Brown(2012) warned that the construction of DDPs “mayinduce excess pore water pressures in thesurrounding soil, which could result in water intrusion

into a newly constructed pile as the excess porepressure dissipates.”

3 APPLICABILITY

The technique is ideally suited for a wide spectrum ofsoil conditions ranging from sandy gravel to clay, withthe caveat that the soil is able to be both displacedand compacted. In cohesionless soils, displacementpiles are appropriate in loose to medium-dense soilconditions, where the relative density (Dr) is less thanabout 65%, the cone tip resistance (qc) is less thanabout 14 MPa (2,000 psi), and/or SPT N-values areless than 30 blows/0.3 m (or 30 blows/ft). Due to thecompactive nature of the displacement tool, the voidspace is decreased, the structure is reorganized, andthe relative density increased, which has a positiveeffect on the behavior of the DDP. NeSmith (2002)reported that the installation of displacement piles indense cohesionless soils (qc greater than 14 MPa or2,000 psi) can be difficult and uneconomical.

In cohesive soils, displacement piles areappropriate in soft to stiff soil consistency, where theundrained shear strength does not exceed about 100kPa (2,000 psf) or where SPT N-values are less thanabout 10 blows/0.3 m (or 10 blows/ft). During

installation, the cohesive soils undergo plasticdeformation and are compacted. Stiff cohesive soils,however, are difficult to compact. Brown (2012)indicated that “residual soil profiles, weak limerockformations, cemented sands, and stiff clays are soiltypes that favor easy construction” of displacementpiles. Reporting on conditions in the United Kingdom,Baxter et al (2006) described that applicableconditions for the use of DDP include sites with“alluvium, soft clays, loose sand, or chalk.” DDPsshould be considered as an alternative toconventional CFA piles in instances where a weak

layer is underlain by a stronger, more competentlayer(s) at moderate depths, and where potential soilmining and effects from ground vibrations would be aconcern (Brown, 2005).

According to Bustamante and Gianeselli (1998),the performance of DDP may be compromised due topossible difficulties encountered during installation invery loose sandy soils or very soft clayey soils(characterized by SPT N-values


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through a grout port (with disposable plug) or apivoting gate located near the bottom of the tool or drillstring (used with a re-usable drilling tip) or through thebottom of the drill string (used with a sacrificial drillingtip). The pressure used to pump the concrete or groutshould be correlated to the ground conditions at thepile location, and should be established using a pre-production test program. NeSmith (2002) indicatedthat for loose to medium-dense cohesionless soils,the initial “target lift-off” grout pressure should bewithin the range of about 140 to 210 kPa (20 to 30 psi)and between 70 to 105 kPa (10 and 15 psi) for theremainder of the grouting. As the bottom of the drillstring approaches the ground surface, the pressureshould be gradually decreased according to the in situstress state. When the tool is within about 1.5 to 3 m(5 to 10 ft) of the surface, the pressure should bedecreased to zero and the pumping stopped.

As described in Section 5, rotation of thedisplacement tool may or may not occur, depending

on the tool and technique utilized. The concrete mixor the grout mix contains many similar components:Portland cement, aggregate (fine aggregate for grout),water, fly ash, and admixtures. The admixtures affectand control the rate of hydration (for workability andset time), and the water reducers (e.g., plasticizers)affect the amount of water needed for fluidity andflowability to ensure the fresh concrete can get to itsintended location without clogging the lines. Brown(2005) reported that the concrete or grout mix shouldprovide “that all solids remain in suspension withoutexcessive bleed-water, must be capable of beingpumped without difficulty, penetrate and fill open voidsin the adjacent soil, and allow for insertion of the steel

reinforcement.” Therefore, a high slump, fluidconcrete or grout mix (with aggregates of fine gravelwith a máximum particle size of 18 mm (¾-inches))should be used. Through the action of thedisplacement tool, the borehole wall is compacted andis relatively smooth, which reduces the concreteoverbreak and eliminates risk of over-augering.

4.3 Insertion of Steel Reinforcement

Depending upon the technique used to constructthe DDP, the steel reinforcement (cages, bars,beams, etc.), when required, can be placed eitherprior to or after the extraction of the tool and

concreting. For displacement tools that have a largeinternal passage (Figure 3), it is possible to insert thesteel reinforcement inside the hollow stem prior to theplacement and injection of concrete. In this instance,the tip at the end of the tool is sacrificial, and servesas the injection location for the concrete. The tool isthen extracted during the concreting process.

For most techniques, however, the steelreinforcement is inserted after the tool has beenextracted, the concreting completed, and while theconcrete is still fresh. Depending upon depth,reinforcement configuration, and fluidity of the

concrete, the reinforcement may need to be pushedor vibrated into place.

Figure 3. Photograph of sacrificial tip, lower section of acylindrical displacement tool, and the internal passagewithin the hollow stem of the tool.

5 TYPES OF DISPLACEMENT PILES & TOOLS

As Brown (2012) explained, “the torque and crowdrequired to construct a drilled displacement pile issubstantial…the energy required to install the pile isrelated to the resistance of the soil to thedisplacement, and so the piles are often installed to adepth that is controlled by the capabilities of thedrilling rig.” For the installation of conventional DDPs,modern hydraulic drilling/piling rigs are capable ofproducing high torque (≥500 kN-m or ≥370,000 ft-lb)and large crowd forces (450 kN or 100,000 lb), whichare needed for the desired pile diameters and depths.

Paniagua (2006) provided a detailed history of theevolution of DDPs and the principal advancements

realized during each of these three generations. Basuet al (2010) present a comprehensive narrative andthorough review for many of the different tools andtechniques used to construct displacement piles inEurope and North America. It is important to note thatthe advancements made in DDP technology are thedirect result of contractors and equipment/toolingmanufacturers developing practical solutions to actualproblems and issues.

The early methods (prior to the 1970s) used toconstruct displacement piling (“first generation” piles)focused on either soil removal during theadvancement of the tool or on the insertion of largecasing into the ground during advancement.Moreover, relatively low torque (50-100 kN-m or37,000 to 74,000 ft-lb) was required by the drillingequipment to perform these piles, but the productionwas slow. The methods comprising these firstgeneration piles include: Atlas piles, DeWaal piles,Franki VB piles, Fundex piles, and Olivier piles. Thenext version of displacement piles emerged during the1970s and improved upon the production rateachievable during advancement by adding partialauger flighting near the bottom of the tooling.Methods comprising this second generation of


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displacement piling include: Pressodrill pile, Tubexpile, SVB pile, and SVV pile. Since the 1980s andeven moreso during the last two decades, there hasbeen advancements in the tooling (e.g., increaseddiameters, and design of the flights and body toincrease production), techniques (e.g., reducedvibrations, spoils, and noise), and drilling equipment(e.g., greater torque and pulldown crowd force, whichpermit larger diameters and greater depths). Methodscomprising this third generation of DDP include:Omega pile, Berkel Auger Pressure GroutedDisplacement (APGD) pile, Menard controlledmodulus columns, Trevi Discrepiles, anddisplacement piles constructed using the SoilmecTraction Compaction Tool (TCT).

To highlight the main differences among selectdisplacement piling methods, the following sectionsprovide a succinct overview of select techniques. Aschematic of four displacement piling methods(DeWaal pile Fundex pile, Omega pile, and Berkel

APGD pile), photographs of different SoilmecDiscrepile tools, and a schematic of the SoilmecTraction Compaction Tool are provided in Figures 4,5, and 8, whereby both the displacement mechanismcan be discerned and the differences in the shape ofthe completed DDP can imagined.

5.1 DeWaal Pile

During the drilling phase, the De Waal displacementtool (Figure 4b) is advanced downward into theformation using clockwise rotation and crowd force.Once the desired depth is reached, concrete is placedinto the hollow stem of the drill string to a prescribed

distance above the ground surface (i.e., head), andthen the sacrificial tip at the bottom of the

(a) (b) (c) (d)Figure 4. Schematic of select Displacement Pile methods:(a) DeWaal Pile, (b) Fundex Pile, (c) Omega Pile, and (d)Berkel APGD Pile (modified after Basu and Prezzi, 2005).

tool is released. The tool and drill string are extractedusing clockwise rotation while maintaining a constanthead of concrete within the hollow stem, resulting in arelatively smooth surface. The steel reinforcement is

typically inserted into the borehole after the concretehas been placed but while it is still fresh. In someinstances, the steel reinforcement can be inserted intothe hollow stem prior to the placement of concrete.Typical diameters achievable with this techniquerange from about 300 to 600 mm (12- to 24-inches),and to a maximum depth of about 25 m (82 ft).

5.2 Fundex Pile

For Fundex displacement piles, the tool with a conicalauger tip (Figure 4c) is advanced downward into theformation with clockwise rotation and crowd force,thereby displacing the soil radially outward. Once thedesired depth is reached, steel reinforcement isinserted into the hollow stem, the sacrificial drilling tip,which forms the enlarged pile bottom, is released, andconcrete is placed into the hollow stem. The tool/drillstring are then extracted using an oscillating up-and-down motion along with a 180° clockwise-counterclockwise rotation, while ensuring theconcrete is maintained at desired level within casing.The withdrawal process produces a nearly smoothshaft. The possible diameters and lengths for Fundexpiles range from about 450 to 675 mm (17.5- to 26.5-inches) and to a maximum depth of about 35 m (115ft), respectively (Basu et al, 2010).

5.3 Omega Pile

As shown in Figure 4d, the diameter of the flangealong the length of the Omega tool and partial augerflights increases gradually and similarly from bothends of the tool toward the displacement body (withmaximum diameter). For displacement pilesconstructed using this method, the tool (with a varyingdiameter) and drill string are advanced downward intothe formation using clockwise rotation and crowdforce. Once the desired depth has been reached,concrete is injected under pressure and the sacrificialtip is released. During the extraction of the tool whilemaintaining a clockwise rotation, concrete is injectedunder pressure until the tool and drill string are fullyextracted from the borehole. The reinforcement cageis inserted (assisted by vibratory means and/ordownward force) down into the fresh concrete. Forsome Omega piles, it is possible to place the steelreinforcement (e.g., cage or bar) into the drilling stemprior to the placement of concrete (Bottiau, 2006).

5.4 Berkel (APGD) Pile

For the Berkel Auger Pressure Grouted Displacement(APGD) pile, the tool (Figure 4e) is advanceddownward into the formation with clockwise rotationand crowd force. Once the desired depth is reached,high-strength grout is injected under pressure throughthe hollow stem of the drill string. Once the initialtarget pressure is achieved, the extraction of the toolmaintaining a clockwise rotation and grouting of the


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borehole is initiated. Pressurized grouting iscontinued along clockwise rotation of the tool until thetool and drill string are fully extracted from theborehole. After the tool is removed from the boreholeand while the grout is still fresh, the steelreinforcement is inserted in the grouted hole.Essentially, two types of APGD piles can beconstructed: (1) partial displacement piles in loose todense sands (with N


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5.5.1 Case History – La Prua Business Center;Rimini, Italy

To support the proposed mixed-use residential andbusiness structures for the new La Prua BusinessCenter located along the waterfront in Rimini (Figures6 and 7), the design engineer estimated that more

than 20,000 linear meters (65,000 linear feet) of boredand/or driven piling would be required to support thebuilding structures. At this site, the generalsubsurface profile consisted of a layer of silt with sandand clay to a depth of about 3.1 m (10 ft) underlain bya 7.8 m (25.5 ft) thick layer of medium-coarse sandwith silt and rounded pebbles, which was underlain bya 14.05 m (46 ft) thick layer of clayey silt with tracesof organics. Beneath the clayey silt layer, there is a2.1 m (6.9 ft) thick layer of medium sand with siltygravel, underlain by a 1.1 m (3.6 ft) layer of gravel withsand and silt, which is then underlain by a 6.8 m (22.3ft) thick layer of clayey silt and clay with interbeddedlenses of sand.

Figure 6. Aerial photograph of the location (outlined in red)for the proposed mixed use, residential-commercialstructure.

Figure 7. Axonometric illustration of the proposed mixeduse, residential-commercial structure.

The original foundation options (Figure 8) includedbored piles stabilized with bentonite slurry duringdrilling and driven piling. However, it was deemed thatthe driven piling operations would have causedexcessive environmental concerns (e.g., noise andvibrations) to the nearby residents and surroundingbuildings, respectively. In addition, there was concernthat the bored pile operations, especially the use ofbentonite slurry, would have issues related to thecleanliness of the jobsite and effect on thesurrounding roads resulting from the truckstransporting the excavated and removed the spoils.

Figure 8. A portion of the plan view of the foundationstructure layout beneath the curved structure and the middlestructure.

As an alternative to conventional piling, thegeotechnical specialty contractor, Trevi S.p.A.,proposed using unreinforced displacement pilesinstalled in a diamond shaped pattern for groundimprovement beneath the structures (Figure 9).There was concern expressed by the owner / engineerthat the unreinforced displacement pile elementswould not provide structural support should it berequired or needed. To ensure adequate support forthe structures and allay any concern by the owner, thecontractor performed a compression test on asacrificial, non-production displacement pile (Figure10). As shown in Figure 11, at a load of about 176tons, the top and creep displacements wereapproximately 8.5mm (5/16 inch) and 3mm (1/8 inch),respectively.


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(a)

(b)Figure 9. (a) Trucated plan view showing the pattern of theinstalled displacement piles, and (b) photograph of twoexposed tops of completed displacement piles.

Figure 10. A photograph of the compression test loadframe. Note: a steel sleeve was used to laterallyrestrain/support the exposed portion of the displacementpile.

(a)

(b)

Figure 11. Graphical depiction of the load-displacementbehavior from (a) a compression load test on anunreinforced displacement pile, and (b) a creep load testperformed with a constant load maintained for 60 minutes.

In total, about 1,600 piles with a diameter of about600 mm (24-inches) and an approximate length of 25m (82 ft) were installed using a conical displacementtool and a Soilmec SR-65 drill rig. Due to thecompactive nature of the tool and the resulting face ofthe borehole wall, the concrete overbreak was kept toa minimum, as anticipated, and averaged between5% and 10% above theoretical. In addition, the drillspoils that needed to be disposed were also kept to a

minimum, where the disposal volume averagedbetween 5% and 10% of the total volume of installedpiling.

5.5.2 Case History – Monselice Hospital; Monselice,Italy

Located southeast of the Euganean Hills andsouthwest of Padua in Italy, the Monselice Hospital islocated in a town with a population of 18,000inhabitants and in an area with substantial geothermicactivity, leading to the popularity of local hot springs


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and mud spas. By working with nature, the building’sdesigners incorporated the use of the undergroundgeothermal resource to heat and cool the hospital.The foundation for the hospital was constructed usingdisplacement piling technology to maximize thebenefit of minimal removal of the drilling spoils, noise,and vibration. The geology below the hospital wasvery amenable to displacement piling constructionbecause it was characterized by fine to medium-density sand (SPT N-values≤45) and silty clay with thegroundwater table located about 0.9 m (3 feet) belowthe ground surface.

The displacement piles were installed by TreviS.p.A. using a Soilmec SR-80 drill rig fitted with thedisplacement pile kit and the conical displacementtool (Figure 12). The in situ soil was displaced andcompacted radially during downward penetrationduring the drilling phase.

Figure 12. Installation of displacement piles using a SR-80drill rig and a conical displacement tool.

During the extraction phase, concrete was injectedat the tip of the tool as the drill string was extracted.When the tool was out of the hole, the reinforcementcages equipped with geothermal loops were theninstalled in the fresh concrete. The geothermal loopswere incorporated into the displacement piles to takeadvantage of the stable subterranean temperatureswhere to provide the hospital with heat in the winter

and air conditioning in the summer. The piles wereabout 600 mm (24-inches) in diameter and ranged inlength from about 17 to 24 m (55 to 80 ft), resulting ina total of about 44,000 linear meters (144,300 linearfeet) of displacement piling. The average dailyproduction of displacement piling was about 16 pilesper day or about 350-380 m per day (1,150 to 1,250ft/day).

To provide control and monitoring during the drillingand concreting phases, the contractor utilized themonitoring system (Soilmec Drilling Mate System,“DMS”) that was integrated into the SR-80 drill rig.

The monitoring system allowed the drill rig operatorsand jobsite personnel to monitor and accuratelycontrol the machine (e.g., drilling parameters and rigperformance) in real time. Data from the DMS wasalso streamed to a remote computer where jobsitemanagers were able to monitor, process, anddocument the project information.

6 SOILMEC TCT – A NEW DDP TOOL

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