june 15, 2016 alberta transportation floor, 803 manning ... landslides... · several slope...

160615DL S02 Instrumentation Priddis.docx A05115A03

Klohn Crippen Berger Ltd. • Suite 301, 2627 Ellwood Drive SW • Edmonton AB T6X 0P7 • CANADA 780.444.0706 t • 780.481.2431 f • www.klohn.com

June 15, 2016

Alberta Transportation 2nd Floor, 803 Manning Road NE Calgary, Alberta T2E 7M8 Ross Dickson Project Services Technologist Dear Mr. Dickson: CON0017609 Southern Region GRMP Instrumentation Monitoring Site S002; H22:14, km 12.95 Priddis Section C - 2016 Spring Readings DRAFT

1 GENERAL

Two slope inclinometers (SI#9 and SI#11) and four vibrating wire piezometers (VW98077, VW98079, VW98081, and VW98083) were read on June 13, 2016 by Mr. Peter Roy, P.Eng. of Klohn Crippen Berger Ltd. (KCB). The site is located on Highway 22:14, approximately 10 km southeast of Bragg Creek, Alberta. The slope failure site is located on the westbound lane and north shoulder of the highway.

The slope inclinometers (SIs) SI#9 and SI#11 were initialized on April 26, 2001 and June 27, 2000, respectively by AMEC. Instrument installation records were not available at the time of preparation of this report. The vibrating wire piezometers (VWPs) 98077 and 98079 were installed March 5, 2009; and 98081 and 98083 were installed April 16, 2009 by AMEC. Several slope inclinometer, pneumatic piezometers and settlement gauges are inoperable as they have either been destroyed, sheared, or lost (buried due to ongoing roadway maintenance). The SIs and piezometers were installed to monitor the performance of a pile wall and two pumping wells installed in the early 1990’s.

The slope inclinometers (SIs) were read using a different Slope Indicator SI probe and cable from previous readings. For similar reasons, AMEC reset the SI plot baselines in 2014 when they used a new probe to read the SIs. The VWPs were manually read using a Slope Indicator VW readout box model 52613500. The data from a VW mini-logger connected to 98077 was downloaded using the program Logger Manager. A second VW mini-logger connected to 98079, which was not functioning properly during AMEC’s last site visit in October 2015, was re-installed.

Instrumentation installation details are provided in Table 1.1. Instruments are located as shown on appended Figure S02-1, previously prepared and submitted by AMEC.

DRAFT

Alberta Transportation CON0017609 Southern Region GRMP

S02 Instrumentation Report 2016 Spring Readings

160615DL S02 Instrumentation Priddis.docx

A05115A03 June 2016

Table 1.1 Instrumentation Installation Details

Instrument # Location1 Date

Installed Stickup2

(m) Depth3

(m) Total Cumulative Resultant Movement

from A0 groove direction1 Lat Long SI#9 50°54’.446 114°25’.152 Apr 2001 -0.38 9.5 0o

SI#11 50°54’.443 114°28’.159 Jun 2000 -0.34 10.5 0o VW98077 50°54’.452 114°28’.091 Mar 2009 N/A 9.3 N/A VW98079 50°54’.477 114°28’.107 Mar 2009 N/A 8.7 N/A VW98081 50°54’.452 114°28’.091 Apr 2009 N/A 7.0 N/A VW98083 50°54’.477 114°28’.107 Apr 2009 N/A 10.9 N/A

1Instrument locations and A0 directions previously reported by AMEC were confirmed by handheld GPS +/- 5 m. 2 The op of SI casings were buried, discussed further below. 3 SI installation depths were not available at the time of preparation of this report. Depths are based on SI readings.

2 INTERPRETATION

2.1 General

Plots of the SI and piezometric data are appended and summarized in the following sections.

Reading SIs using two different SI probes and cables can create errors when the data collected with a “new” probe is compared to previous datasets collected with another probe. Errors created and exacerbated by the tilt of the SI casing are further discussed in Section 2.3.

2.2 Zones of Movement

The identification of new movement zones was hindered by data interpretation issues encountered from changing SI probe and cable from previous recordings and the tilt recorded in the SI casings.

Previous readings of the Sis indicated movement in the upper 2 m in SI#9 and in the upper 3 m in SI#11. However, no significant movement has been measured since the plots were re-initialized in May 2014.

2.3 Interpretation of Monitoring Results

Errors created by changing SI cables and probes during monitoring programs are created when casing tilt is greater than or equal to three degrees. The tilt of the SI casings in the A- and B-directions are shown on the absolute position plots for both SI#9 and SI#11, appended. Furthermore, in non-vertical casing, depth control becomes an issue, and slight differences between the old control cable and the new control cable can make difference in readings which are observed in the A- and B-direction incremental deflection plots for both SI#9 and SI#11, appended. Dataset errors can also be identified when the incremental deflection plots have sinusoidal or ‘snaking’ trends.

The absolute position and tilt angle for each SI casing is summarized in Table 2.1.

DRAFT




A05115A03 June 2016

Table 2.1 Absolute Position and Tilt of SI Casing

Instrument Date Initialized

A-Direction Absolute Position and Casing Tilt

Angle

B-Direction Absolute Position and Casing

Tilt Angle Comment

SI#9 2001 300 mm from top to bottom. Tilt varies

between 0o – 6o

400 mm from top to bottom. Tilt varies

between 0o – 4o

Tilt angle greater than recommended range (see absolute position plot)

SI#11 2000 150 mm from top to bottom. Tilt of 1o

350 mm from top to bottom. Tilt varies

between 2o – 3o

Tilt angle near recommended maximum (see absolute position plot)

Each SI read had tilts up to or greater than three degrees identified in the absolute position plots appended. In addition, the incremental deflection plots for both SIs have a ‘snaking’ trend as a results from a change in depth control from SI cable change and operator change.

In the interim, the 2016 spring readings will be used as a new initial data set for future interpretation using the same SI cable and probe. As a result, there is currently no SI monitoring data to interpret as readings will be considered initialization of a new dataset. Instrument summary tables will be included in the fall 2016 Section C instrument letter.

Both SI#9 and SI#11 were covered with about 20 cm of sand and gravel inside of their flush-mounted head boxes, below the highway surface. Furthermore, some of the fine debris had entered the SI casing can caused some obstruction to the probe during readings. These installs may become inoperable as they were difficult to read due the depth below grade resulting from ongoing asphalt placement during maintenance over the years.

A summary of VWPs 98077, 98079, 98081, and 98083 are in Table 2.2. Plots of the piezometric elevation for each are appended.

Table 2.2 VW Readings Summary

Instrument Date Installed Tip El. (m)1 Ground

El. (m)

Current Pressure

Head Above Tip (m)

Previous Pressure

Head Above Tip (m)

Current Water Level

(mbgs1)

Change from Previous

Reading (m)

98077 Mar 2009 1290.7 1300 1.67 1.68 7.62 -0.01

98079 Mar 2009 1291.30 1300 0.24 0.91 8.46 -0.67

98081 Apr 2009 1293.00 1300 Dry Dry N/A N/A

98083 Apr 2009 1289.10 1300 1.70 2.36 9.2 -0.66

1 meters below ground surface (mbgs) 2 Elevations are relative to an approximate site datum previously reported by AMEC.

DRAFT




A05115A03 June 2016

The initial data transmission from AMEC only included raw data; all plots and calculations, including VW calibrations, were removed from the files. The calibration factors were subsequently provided upon request. However, as part of our review of the data, calibration certificates of all VWP piezometers at this site were requested from Slope Indicator and review of the calibration factors provided by both Slope Indicator and AMEC matched. The resulting pore water pressures processed by KCB do not match that reported by AMEC in previous reports. The KCB processed data indicates lower recorded pore water pressures varying between 1.5 and 1.6 m.

Piezometric elevations presented in Table 2.2 are based on data processing completed by KCB.

3 RECOMMENDATIONS

3.1 Future Work

The instruments should continue to be read semi-annually at this site.

3.2 Instrument Repairs

None required.

4 CLOSURE

Please contact the undersigned if you have any questions or comments regarding this report.

This is a draft letter only and we solicit your review and comments within 4 weeks of submission. Upon issue of the final letter, we request that all draft letters be destroyed or returned to Klohn Crippen Berger Ltd. This draft letter should not be relied upon as a final document for design and/or construction.

KLOHN CRIPPEN BERGER LTD. Chris Gräpel, M.Eng., P.Eng Senior Civil Engineer Attachments Figure Appendix I Slope Inclinometer and Piezometer Plots

DRAFT




A05115A03 June 2016

FIGURE AMEC 2015 Site Plan

DRAFT




A05115A03 June 2016

APPENDIX I Slope Inclinometer and Piezometer Plots

DRAFT

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0

Elev.

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LEGEND

Initial 6 May 2014

1 Oct 2014

12 May 2015

20 Oct 2015

13 Jun 2016*

Cumulative Deflection

Direction A

Deflection (mm)


Direction B

Deflection (mm)

Ref. Elevation m

Z:\A\EDM\A05115A03 ABT SOUTHERN REGION GRMP\300 DESIGN\2016\2. PART C INSTRUMENTATION\S02 - PRIDDIS\SI\PRIDDIS-9-NEW.GTL

S2 - 22:14 Priddis, Inclinometer #9

Alberta Transportation

Sets marked * include zero shift and/or rotation corrections.

Klohn Crippen Berger Ltd. - Calgary, AB

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-20 -10 0 10 20

LEGEND

Initial 6 May 2014

1 Oct 2014

12 May 2015

20 Oct 2015

13 Jun 2016*

Incremental Deflection

Direction A

Deflection (mm)


Direction B

Deflection (mm)

Ref. Elevation m






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LEGEND

6 May 2014

1 Oct 2014

12 May 2015

20 Oct 2015

13 Jun 2016*

Absolute Position

Direction A

Position (mm)

Absolute Position

Direction B

Position (mm)

Ref. Elevation m






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0

-50 -25 0 25 50

LEGEND

Initial 6 May 2014

1 Oct 2014

12 May 2015*

20 Oct 2015

13 Jun 2016*


Direction A

Deflection (mm)


Direction B

Deflection (mm)

Ref. Elevation m






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(m)

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0

-20 -10 0 10 20

LEGEND

Initial 6 May 2014

1 Oct 2014

12 May 2015*

20 Oct 2015

13 Jun 2016*


Direction A

Deflection (mm)


Direction B

Deflection (mm)

Ref. Elevation m






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Elev.

(m)

-500 -250 0 250 500

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-500 -250 0 250 500

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(m)

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0

-500 -250 0 250 500

LEGEND

6 May 2014

1 Oct 2014

12 May 2015*

20 Oct 2015

13 Jun 2016*

Absolute Position

Direction A

Position (mm)

Absolute Position

Direction B

Position (mm)

Ref. Elevation m






A05115A03.

AT Southern Region GRMP

2016-06-13

160613 S02-Piezometer Data Priddis.xlsx

1288.0

1290.0

1292.0

1294.0

1296.0

1298.0

1300.0

1302.0

12/18/08 12/03/09 11/18/10 11/03/11 10/18/12 10/03/13 09/18/14 09/03/15 08/18/16

Elev

atio

n (

m)

Date

S02H22:14 Priddis Piezometric Elevation

Ground Elev 98083 Piezo Elev 98083 Piezo Tip El 98077 Tip Elev 98077 Piezo Tip El

98079 Piezo Elev 98079 Piezo Tip El 98081 Piezo Elev 98081 Piezo Tip El

june 15, 2016 alberta transportation floor, 803 manning ... landslides... · several slope...

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