December 2, 2010 Alberta Transportation Landslides... · December 2, 2010 R:\Projects\Calgary...

$: December 2, 2010 Alberta Transportation Landslides... · December 2, 2010 R:\Projects\Calgary Geo\CG25332 - AT Southern Region 2010\300 - Semi-Annual Readings (C)\S10A\Fall Report\Fall$
AMEC Earth & Environmental A division of AMEC Americas Limited 140 Quarry Park Blvd. SE Calgary, AB, CANADA T2C 3G3 Tel +1 (403) 248-4331 Fax +1 (403) 248-2188 www.amec.com

R:\Projects\Calgary Geo\CG25332 - AT Southern Region 2010\300 - Semi-Annual Readings (C)\S10A\Fall Report\Fall 2010 Monitoring - S10(A),FINAL,ab,bb,tc.doc

Page 1

December 2, 2010

CG25332.300

Mr. Ross Dickson

Alberta Transportation

2nd Floor, 803 Manning Road NE

Calgary, AB T2E 7M8

Dear Ross:

Re: Southern Region Geohazard Assessment

Fall 2010 Instrumentation Monitoring Results

Site S10(A): Highway 762:02, Archery Range

This letter documents the Fall 2010 instrument readings at the above-noted site and can be

inserted into Section C of the site binder. The updated site plan, instrument data, and plots are

also attached and can be inserted into Section D of the site binder.

1.0 OBSERVATIONS

1.1 Field Program and Instrumentation Status

Three slope inclinometers (SI’s) and two pneumatic piezometers were read at the S10(A) –

Archery Range site, on Hwy 762:02, on October 12, 2010 by Mr. Tyler Clay, EIT, of AMEC

Earth and Environmental (AMEC), a division of AMEC Americas Limited.

The SI’s were read using a metric Slope Indicator probe and Digitilt Datamate readout

manufactured by Durham Geo Slope Indicator (DGSI). Inclinometer reading depths were

referenced to the top of the SI casing. The piezometers were read with a readout unit

manufactured by DGSI.

The SI’s and piezometers at the site were installed to monitor a landslide downslope of the road

with a headscarp through the southbound lane. Please refer to Figure S10-1 attached in

Section D for a site plan showing the instrument locations.

Alberta Transportation Fall 2010 Instrumentation Monitoring Results Southern Region Site S10(A) – Highway 762:02, Archery Range December 2, 2010


Page 2

2.0 INTERPRETATION AND RECOMMENDATIONS

2.1 General

Plots of the SI data are presented in Section D and are summarized in the following sections.

Where applicable, the resultant movement has also been plotted. Note that all elevations are

referenced to a site datum of 1000 m.

2.2 Zones of Movement

No new movement zones have been detected since the previous readings in May 2010. Zones

of previous movement and historical results are summarized in Table S10-1.

2.3 Interpretation of Monitoring Results and Recommendations

2.3.1 Interpretation

SI 2007-11 Southbound Lane

(Figures S10-3, 4 and 9)

The readings from this SI indicate continued movement at the previously-noted

movement zone around 991.6 m elevation (roughly 7 m depth below the road

surface), with approximately 20 mm of movement since May 2010. The rate of

movement has had a seasonal acceleration since the previous reading in

May 2010, increasing from 7 mm/yr to 45 mm/yr. The movement rate is

comparable to the acceleration measured during the summer of 2008. There is a

second zone of lesser movement at approximately 988 m elevation that has

shown approximately 6 mm of displacement since initialization in 2007. The

movement rate here appears to have increased from 0.4 mm/yr in May 2010 up

to 2 mm/yr based on the current readings.

SI 2007-12 Northbound Lane


Since May 2007, there has been approximately 5 to 6 mm of movement at a

compass bearing of 235° around 991 m elevation, which corresponds to the

boundary between the native soils and the underlying till at approximately 8 m

depth at this location. As shown on the displacement vs. time plot on Figure S10-

9, the movement has been ongoing at a very slow, steady rate without any sign

of the seasonal (summer) movements as measured in SI’s 2007-11 and 2009-01.

SI 2009-01 Adjacent To Toe of Highway Embankment Slope


This SI was installed and initialized in February 2009, and has detected ongoing

movement at approximately 988 m elevation (contact between native silt and clay



Page 3

and underlying till), and also at 991 m elevation (within the native silt and clay).

The rate of movement has had a seasonal acceleration since the previous

reading in May 2010. The movement rate is comparable to the rate measured at

SI 2007-11 during the summer of 2008.

Borehole 2007-13 Piezometer Data (Figure S10-10):

• The October 2010 reading of piezometer 60225 shows a slight increase in pressure from

the Spring 2010 reading. The reading is comparable to readings since 2007. This tip is

located within the native silt and clay.

• The piezometer tip (60224) installed in the granular road fill has measured a slight

increase in piezometric pressure since the Spring 2010 reading.

As shown on the cross-section on Figure S10-2, the ground movement detected in SI’s 2007-11

and 2009-01 along with the apparent toe bulge in the forested area further downslope of the

highway line up well along an arc-shaped failure surface connecting to an oversteepened

headscarp daylighting around the centerline of the highway (consistent with visible damage

along the road). If this is the case, the minor, slow movements detected in SI 2007-12 as well as

around 987.5 m elevation in SI 2007-11 may be indications of impending progressive

movements in response to the main movement that is causing the damage to the highway.

2.3.2 Recommendations

AMEC recommends the following for this site:

• Proceed with a repair design for this site. AMEC has submitted a report on repair

alternatives, and has selected the toe berm option as the most favourable. AMEC can

proceed with a repair design and a draft tender package preparation upon AT’s

approval.

• The semi-annual instrument readings and annual site inspections by AT and

geotechnical consultant personnel should be continued in order to monitor the active

ground movement.



Page 4

3.0 INSTRUMENTATION REPAIRS AND MAINTENANCE REQUIRED

The top of the casing at SI 2007-11 is now well below the road surface elevation due to

successive overlays. The casing protector should be raised, and an extension should be

installed on the SI casing. AMEC will submit a proposal to perform this repair under separate

cover.



Page 5

TABLE S10-1

FALL 2010 – ARCHERY RANGE

Slope Inclinometer Instrumentation

Reading Summary

Date Monitored: October 12, 2010

INSTRUMENT

NAME AND

COORDINATES

(LATITUDE

AND

LONGITUDE)

DATE

INITIALIZED

TOTAL

CUMULATIVE

RESULTANT

MOVEMENT AT

DEPTH SINCE

INITIAL

READING

MAXIMUM

RATE OF

MOVEMENT

CURRENT

STATUS

DATE OF

PREVIOUS

READING

SINCE PREVIOUS READING

INCREMENTAL

MOVEMENT

RATE OF

MOVEMENT

CHANGE IN

RATE OF

MOVEMENT

2007-11

(50°49’.680N,

114°29’.399W)

May 22, 2007

73.6 mm over

5.9 to 7.1m at

226°

82mm/yr

(May to Sept

2008)

Operational May 3, 2010 20.2 mm 45.5 mm/yr +44.6 mm/yr

2007-12

(50°49’.680N,

114°29’.399W)

May 22, 2007 5.5 mm at 7.7m

at 244°

2.6mm/yr (June

to September

2007)

Operational May 3, 2010 0.9mm 2.1 mm/yr +2.0 mm/yr

2009-01

(co-ords n/a)

February 23,

2009

44.8 mm at 4 to

5.5 m depth, at

274°.

71.1mm/yr (Early

May to Mid

October 2010)

Operational May 3, 2010 31.6 mm 71.1 mm/yr +69.4 mm/yr



Page 6

TABLE S10-2

FALL 2010 – ARCHERY RANGE

Piezometer Instrumentation

Reading Summary

Date Monitored: October 12, 2010

INSTRUMENT

TIP SERIAL

NUMBER AND

COORDINATES

(LATITUDE AND

LONGITUDE)

DATE

INITIALIZED

TIP

ELEVATION*

(m)

GROUND

ELEVATION*

(m)

CURRENT

STATUS

MAXIMUM

PIEZOMETRIC

ELEVATION

(m)

CURRENT

PIEZOMETRIC

ELEVATION

(m)

PREVIOUS

PIEZOMETRIC

ELEVATION

(m)

CHANGE IN

CALCULATED

EQUIVALENT

GROUNDWATER

ELEVATION SINCE

PREVIOUS READING

(m)

PORE

WATER

PRESSURE

RATIO

(ru)

60225

(50°49’.676N,

114°29’.401W)

4/12/2007 991.51 999.13 Operational 999.1 m

(October 2009) 993.77 993.18 +0.59 m 0.16

60224

(50°49’.676N,

114°29’.401W)

4/12/2007 994.56 999.13 Operational 995 m

(October 2009) 995.43 994.66 +0.77 m 0.1

*Relative to assumed site bench mark of 1000 m.



Page 7

4.0 CLOSURE

This report has been prepared for the exclusive use of Alberta Transportation for the specific

project described herein. Any use which a third party makes of this report, or any reliance on or

decisions to be made based on it are the responsibility of such third parties. AMEC Earth &

Environmental, a division of AMEC Americas Limited, cannot accept responsibility for such

damages, if any, suffered by any third party as a result of decisions made or actions based on

this report. This report has been prepared in accordance with accepted geotechnical

engineering practices. No other warranty, expressed or implied, is made.

We trust that this meets your needs at this time. Please contact the undersigned if you have any

questions or require any further information.

Respectfully Submitted,

AMEC Earth & Environmental,

a division of AMEC Americas Limited

ORIGINAL SIGNED:

DECEMBER 2, 2010

Tyler Clay,B.A.Sc., EIT Bryan Bale, M.Sc., P.Eng.

Geological Engineer Geotechnical Engineer

Reviewed by: APEGGA Permit to Practice No. P-04546

Andrew Bidwell, M.Eng., P.Eng.

Associate Geological Engineer

R:\Projects\Calgary Geo\CG25332 - AT Southern Region 2010\300 - Semi-Annual Readings (C)\S10A\Fall Report\Fall 2010 Monitoring -

S10(A),FINAL,ab,bb,tc.doc

SECTION D

Southern Region Geohazard Assignment

Site S10(A) – Archery Range

Fall 2010 Instrument Data and Plots

1000

1005A A'

NORTHEAST SOUTHWEST

Fill

Fe

nce

line

Bo

reh

ole

2

00

7-1

2

Bo

reh

ole

2

00

7-1

1

Fe

nce

line

Tre

elin

e/S

W e

dg

e o

f cle

are

d r

igh

t-o

f-w

ay

Cracking/headscarp visible around road centerline

985

990

995

1000

1005

Ele

va

tio

n (

m)

Bo

reh

ole

2

00

9-0

1

Minor movement, possibly secondary to main movement detected at SI's 2007-11 and 2009-01

A A'

NORTHEAST SOUTHWEST

Fill(granular)

Fill(reworked till)

Native Silt &Clay

Till

Fe

nce

line

Bo

reh

ole

2

00

7-1

2

Bo

reh

ole

2

00

7-1

1

Fe

nce

line

Lobe of possible toe bulge visible in treed area

Tre

elin

e/S

W e

dg

e o

f cle

are

d r

igh

t-o

f-w

ay


?

?

?

975

980

985

990

995

1000

1005

Ele

va

tio

n (

m)

Bo

reh

ole

2

00

9-0

1


A A'

NORTHEAST SOUTHWEST

Fill(granular)

Fill(reworked till)

Native Silt &Clay

Till

Fe

nce

line

Bo

reh

ole

2

00

7-1

2

Bo

reh

ole

2

00

7-1

1

Fe

nce

line


Tre

elin

e/S

W e

dg

e o

f cle

are

d r

igh

t-o

f-w

ay


?

?

?

Possible, minor.

Client

Project Revision

Nov-10Job No.

File No.:

CG25332.300

Site S10(A) Archery Range Site


Cross Section A

Fig S10-2Date:

975

980

985

990

995

1000

1005

0 5 10 15 20 25 30 35 40 45 50 55 60

Ele

va

tio

n (

m)

Horizontal Distance (m)

Bo

reh

ole

2

00

9-0

1


A A'

NORTHEAST SOUTHWEST

October 2010 equivalent groundwater level calculated from pressure measured by Piezometer 60225 installed at 991.5 m elevation in the native silt and clay.

Movement zone measured in SI

Potential landslide failure surface

Legend

Fill(granular)

Fill(reworked till)

Native Silt &Clay

Till

Fe

nce

line

Bo

reh

ole

2

00

7-1

2

Bo

reh

ole

2

00

7-1

1

Fe

nce

line


Tre

elin

e/S

W e

dg

e o

f cle

are

d r

igh

t-o

f-w

ay

Interpreted Soil Boundary


?

?

?

Possible, minor.

14

12

10

8

6

4

2

0

Depth

(m)

-100 -50 0 50 100

14

12

10

8

6

4

2

0

-100 -50 0 50 100

14

12

10

8

6

4

2

0

Depth

(m)

-50 -25 0 25 50

14

12

10

8

6

4

2

0

-50 -25 0 25 50

LEGEND

Initial 12 Apr2007

7 Jun2007

17 Sep2007

23 Sep2008

20 Oct2009

3 May2010

12 Oct2010

Downslope

Figure S10-3

Downslope

Cumulative Deflection

Direction A

Deflection (mm)

Incremental Deflection

Direction A

Deflection (mm)

Ref. Elevation 998.6m

R:\Projects\Calgary Geo\CG25332 - AT Southern Region 2010\300 - Semi-Annual Readings (C)\S10A\Fall Data\2007-11.GTL

Site S10(A), Inclinometer 2007-11


AMEC Earth & Environmental - Calgary, AB

14

12

10

8

6

4

2

0

Depth

(m)

-100 -50 0 50 100

14

12

10

8

6

4

2

0

-100 -50 0 50 100

14

12

10

8

6

4

2

0

Depth

(m)

-50 -25 0 25 50

14

12

10

8

6

4

2

0

-50 -25 0 25 50

LEGEND

Initial 12 Apr2007

7 Jun2007

17 Sep2007

23 Sep2008

20 Oct2009

3 May2010

12 Oct2010

Northwest

Figure S10-4

Northwest


Direction B

Deflection (mm)


Direction B

Deflection (mm)






14

12

10

8

6

4

2

0

Depth

(m)

-50 -25 0 25 50

14

12

10

8

6

4

2

0

-50 -25 0 25 50

14

12

10

8

6

4

2

0

Depth

(m)

-10 -5 0 5 10

14

12

10

8

6

4

2

0

-10 -5 0 5 10

LEGEND

Initial 12 Apr2007

7 Jun2007

17 Sep2007

23 Sep2008

4 May2009

20 Oct2009

3 May2010

12 Oct2010

Downslope

Figure S10-5

Downslope


Direction A

Deflection (mm)


Direction A

Deflection (mm)






14

12

10

8

6

4

2

0

Depth

(m)

-50 -25 0 25 50

14

12

10

8

6

4

2

0

-50 -25 0 25 50

14

12

10

8

6

4

2

0

Depth

(m)

-10 -5 0 5 10

14

12

10

8

6

4

2

0

-10 -5 0 5 10

LEGEND

Initial 12 Apr2007

7 Jun2007

17 Sep2007

23 Sep2008

4 May2009

20 Oct2009

3 May2010

12 Oct2010

Northwest

Figure S10-6

Northwest


Direction B

Deflection (mm)


Direction B

Deflection (mm)






13

12

11

10

9

8

7

6

5

4

3

2

1

0

Depth

(m)

-75 -37.5 0 37.5 75

13

12

11

10

9

8

7

6

5

4

3

2

1

0

-75 -37.5 0 37.5 75

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Depth

(m)

-30 -15 0 15 30

13

12

11

10

9

8

7

6

5

4

3

2

1

0

-30 -15 0 15 30

LEGEND

Initial 23 Feb2009

16 Apr2009

4 May2009

12 Jun2009

20 Oct2009

3 May2010

12 Oct2010

Downslope

Figure S10-7

Downslope


Direction A

Deflection (mm)


Direction A

Deflection (mm)






13

12

11

10

9

8

7

6

5

4

3

2

1

0

Depth

(m)

-50 -25 0 25 50

13

12

11

10

9

8

7

6

5

4

3

2

1

0

-50 -25 0 25 50

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Depth

(m)

-10 -5 0 5 10

13

12

11

10

9

8

7

6

5

4

3

2

1

0

-10 -5 0 5 10

LEGEND

Initial 23 Feb2009

16 Apr2009

4 May2009

12 Jun2009

20 Oct2009

3 May2010

12 Oct2010

Northwest

Figure S10-8

Northwest


Direction B

Deflection (mm)


Direction B

Deflection (mm)






70

80

Ma

gn

itu

de

of

Re

su

lta

nt

Dis

pla

ce

me

nt

(mm

) S

inc

e B

as

elin

e R

ea

din

g

S10(A) - Archery RangeGround Movement Measured By Slope Inclinometers

2007-11 - Southbound (Downslope) Lane

2007-12 - Northbound (Upslope) Lane

2009-01 - Toe Of Highway Embankment

40

50

60

Ma

gn

itu

de

of

Re

su

lta

nt

Dis

pla

ce

me

nt

(mm

) S

inc

e B

as

elin

e R

ea

din

g

May 4, 2009 - 2007-11 could not be read (paved over).

Please refer to slope cross-section on Figure S10-2 for illustration of elevations and relative positions of ground movement detected in the SI's.

September 2007 to May 2008 -minor movements in both SI's

May to September 2008 -seasonal acceleration of movement in SI 2007-11 with steady movement at a much slower rate in SI 2007-12.

Spring 2009 to Spring 2010 -

May to October 2010 -seasonal acceleration of movement with similiar rates in SI 2007-11 and SI 2007-12.

10

20

30

Ma

gn

itu

de

of

Re

su

lta

nt

Dis

pla

ce

me

nt

(mm

) S

inc

e B

as

elin

e R

ea

din

g

April 2007 - baseline reading of 2007-11 and 2007-12. February 2009 - baseline

reading of 2009-01.

April to September 2007 -active movement in SI 2007-11 with concurrent, minor movement in 2007-12.

minor movements in both SI's 2007-11 and 2007-12.

Movement starts in SI 2009-01 around mid-April and continues through to October 2009 reading.

Spring 2009 to Spring 2010 -movement rates in SI 2007-11 and SI 2009-01 appear to be similar.

2007-12.

Figure S10-9

0

21-Aug-06 29-Nov-06 9-Mar-07 17-Jun-07 25-Sep-07 3-Jan-08 12-Apr-08 21-Jul-08 29-Oct-08 6-Feb-09 17-May-09 25-Aug-09 3-Dec-09 13-Mar-10 21-Jun-10 29-Sep-10 7-Jan-11

Ma

gn

itu

de

of

Re

su

lta

nt

Dis

pla

ce

me

nt

(mm

) S

inc

e B

as

elin

e R

ea

din

g

reading of 2009-01.

995

996

997

998

999

1000

EL

EV

AT

ION

(m

)

Borehole 2007-13 Piezometers

Ground Surface

Tip 60224 - Piezometric Elevation

Tip 60224 - Tip Elevation



Sand and Gravel Fill

Figure S10A -10

991

992

993

994

995

996

997

998

999

1000

12-Apr-07 29-Oct-07 16-May-08 2-Dec-08 20-Jun-09 6-Jan-10 25-Jul-10 10-Feb-11

EL

EV

AT

ION

(m

)

DATE

Borehole 2007-13 Piezometers

Ground Surface





Sand and Gravel Fill

Native Clay Soil

TABLE S10A - 3

PROJECT:

File No.

DESCRIPTION: Hwy 762 S10A

PIEZOMETER:

NUMBER: 60224

STATION: LOCATION: 2007-13

SOIL TYPE: TILL SOIL DENSITY (AVG.): 1790 kg/m3

ELEVATION INITIAL GROUND: 999.13 PIEZOMETER TIP: 994.56DATE PRESENT FIELD FIELD PIEZO PIEZO Ru Rue REMARKS

GROUND READING READING HEAD ELEV.ELEV. (above tip)

(m) (psi) (kpa) (m) (m)12-Apr-07 999.13 0.15 -1.4 0.00 994.56 0.0022-May-07 999.13 0.58 1.6 0.16 994.72 0.0217-Sep-07 999.13 0.09 -1.8 0.00 994.56 0.0021-May-08 999.13 0.00 -2.4 0.00 994.56 0.0020-Oct-09 999.13 1.06 4.9 0.49 995.05 0.063-May-10 999.13 0.49 0.9 0.10 994.66 0.0112-Oct-10 999.13 1.60 8.5 0.87 995.43 0.10 slowly dropping

TABLE S10A-4

PROJECT:

File No. DESCRIPTION: Hwy 762 at S10A

PIEZOMETER:

NUMBER: 60225STATION: LOCATION: 2007-13SOIL TYPE: SILT AND CLAY SOIL DENSITY (AVG.): 1790 kg/m3ELEVATION INITIAL GROUND: 999.13 PIEZOMETER TIP: 991.51

DATE PRESENT FIELD FIELD PIEZO PIEZO Ru Rue REMARKSGROUND READING READING HEAD ELEV.

ELEV. (above tip)(m) (psi) (kpa) (m) (m)

12-Apr-07 999.13 2.84 15.5 1.58 993.09 0.1122-May-07 999.13 3.86 22.5 2.29 993.80 0.1617-Sep-07 999.13 3.69 21.3 2.17 993.68 0.1621-May-08 999.13 3.25 18.3 1.87 993.38 0.1320-Oct-09 999.13 11.60 75.2 7.67 999.18 0.55 Slowly dropping.3-May-10 999.13 2.97 16.4 1.67 993.18 0.1212-Oct-10 999.13 3.82 22.2 2.26 993.77 0.16

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