20 December 2017 Amec Foster Wheeler Reference No.: TT163003 · of track mounted rig and Minute Man (hand-operated rig) equipped with solid stem augers. As the Minute Man was not

20 December 2017

Amec Foster Wheeler Reference No.: TT163003.9000

CH2M HILL Canada Limited

245 Consumers Road

North York, Ontario, M2J 1R3

Canada

Attention: Mr. Rob Wiersma

Dear Sir:

Re: ADDENDEM TO GEOTECHNICAL INVESTIGATION REPORT

(TT163003, dated 16 June 2016)

PROPOSED TEMPORARY BRIDGES A TO F

HIGHLAND SEWERSHED TRUNK SEWER REHABILITATION

SOUTH MIMICO SITE, TORONTO, ONTARIO

Amec Foster Wheeler Environment & Infrastructure, a Division of Amec Foster Wheeler

Americas Limited (“Amec Foster Wheeler”), is pleased to submit this letter report to

provide the results of geotechnical investigation and slope stability analysis for the six

proposed temporary bridges A to F to be constructed at the South Mimico site in the City

of Toronto, Ontario.

This report should be considered as an addendum to Amec Foster Wheeler’s previously-

submitted geotechnical investigation report titled “Geotechnical Investigation Report,

Highland Sewershed Trunk Sewer Rehabilitation, South Mimico Site, Toronto, Ontario”,

Reference No.: TT163003, dated 16 June 2016. Therefore, the previous 2016 report should

be considered as an integral part of this letter report. All the precautionary statements

on how to use the report and the Report Limitations included in the 2016 report are

applicable to this letter report.

This letter report supersedes all reports previously submitted for the six proposed

bridges.


Addendum to Geotechnical Investigation Report

(TT163003, dated 16 June 2016)

Proposed Temporary Bridges A to F

Highland Sewershed Trunk Sewer Rehabilitation

South Mimico Site, Toronto, Ontario Page 2 of 15

Amec Foster Wheeler Environment & Infrastructure

50 Vogell Road

Richmond Hill, Ontario, L4B 3K6

Canada

Tel. No.: (905) 403-5014

amecfw.com

1.0 INTRODUCTION

The purpose of the geotechnical investigation was to characterize the subsurface

conditions at the six proposed bridge foundation locations by means of drilling a total of

eight (8) boreholes (BH 17-1 to BH 17-8) and to provide recommendations on the

geotechnical design of bridge foundations. These eight boreholes were drilled to provide

additional subsurface soil information to the previously-drilled boreholes (BH 4, BH 6,

BH 7 and BH 8, with Record of Boreholes shown in Appendix A) reported in the 2016

report, resulting in two boreholes for each proposed bridge (i.e., one on each bank).

The six proposed temporary bridges (A to F) will be constructed over South Mimico

Creek, as shown on Figure Nos. 1 and 2, as parts of access routes for the rehabilitation

construction.

Authorization to proceed with this investigation was received from Mr. Joshua

VanRavenswaay, Staff Consultant of CH2M, on 1 September 2017. The work carried out

for this investigation was completed in accordance with Contract No.: 10201-7-100848-

M0004, dated 8 June 2017 and Amec Foster Wheeler's proposal dated 22 August 2017.

2.0 INVESTIGATION PROCEDURES

The field work for borehole drilling was conducted from 29 September 2017 to 19 October

2017 under full time oversight of Amec Foster Wheeler personnel.

A total of eight (8) boreholes (BH 17-1 to BH 17-8) were advanced within or close to the

proposed bridge foundation locations as shown on Figure No. 2. Among the eight (8)

boreholes, six (6) boreholes were drilled for each bridge at the west bank, and two (2)

boreholes were drilled for Bridges B and E at the east bank, where no existing borehole

information was available.



(TT163003, dated 16 June 2016)





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All boreholes were terminated in weathered shale, which could be augered through by

the drilling rig, at depths of between 1.7 m and 4.7 m below grade, using a combination

of track mounted rig and Minute Man (hand-operated rig) equipped with solid stem

augers. As the Minute Man was not sufficiently powerful to drill through the fill, a mini

excavator was used to conduct test pits where granular pavement present at ground

surface.

Due to access difficulty, a small drilling equipment (“Minute Man”) was used at all

borehole locations except for BH 17-6. Soil sampling for these boreholes was conducted

by freely dropping a 32 kg (70 lbs.) hammer for a vertical distance of 0.76 m (30 inches)

to drive a 50 mm (2 inch) diameter O.D. split-barrel (split spoon) sampler into the ground.

Half of the number of blows by the smaller hammer weight was recorded as SPT ‘N’

value of the soil.

Soil samples were taken at 0.76 m interval, while performing Standard Penetration Test

(SPT) in accordance with ASTM D1586. The SPT sampling consisted of freely dropping

a 63.5 kg (140 lb) hammer for a vertical distance of 0.76 m (30 inches) to drive a 50 mm (2

inch) diameter O.D. split-barrel (split spoon) sampler into the ground. The number of

blows of the hammer required to drive the sampler into the relatively-undisturbed

ground by a vertical distance of 0.30 m (12 inches) was recorded as SPT ‘N’ value of the

soil which indicated the compactness of cohesionless soils or implied the consistency of

cohesive soils. The results of SPT are shown in the Record of Boreholes.

The MTM NAD 27 coordinates system was used to survey the as-drilled borehole

locations upon completion of drilling, and the geodetic ground elevations of the

boreholes were surveyed using the elevations of the maintenance hole covers provided

by CH2M, as shown in Figure No. 2 and Table 2.1.



(TT163003, dated 16 June 2016)





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The soil samples were transported to Amec Foster Wheeler’s Advanced Soil Laboratory in Scarborough (Toronto). All the soil samples were re- examined and selected samples were tested for water contents, Atterberg Limits and grain size distribution. The test results are shown on the Record of Boreholes and summarized in Section 3.0.

3.0 SUBSURFACE CONDITIONS

Based on the OGS Map M2544, Bedrock Geology of Ontario, the underlying bedrock at

the site is the Georgian Bay Formation, which comprises shale, dolostone, interbedded

siltstone and minor limestone.

Based on the soil conditions encountered at the boreholes, the soil profile comprised, in

descending order, topsoil, sandy gravel and /or sandy silt fill, silty clay, weathered shale

which could be augered through and shale bedrock which typically caused auger refusal.

The subsurface soil conditions are briefly described herein and additional information is

provided in the Record of Boreholes.

3.1 Stratigraphic Units

3.1.1 Ground Surface Cover

Topsoil

Topsoil was present at the ground surface of Boreholes BH 17-1 to BH 17-3, BH 17-7 and

BH 17-8. The thickness of topsoil varied from 100 mm to 225 mm. Water contents of the

topsoil varied from 12 % to 15 %.

Sandy Gravel Fill

Sandy gravel fill was present at the ground surface of Boreholes BH 17-4 to BH 17-6 with

a thickness of 0.3 m to 0.9 m. Water contents of the sandy gravel fill were between 3 %

and 7 %.



(TT163003, dated 16 June 2016)





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3.1.2 Fill Soils

Brown to grey sandy silt fill was found at all the borehole locations below the ground

surface cover at the site, and extended to a depth of 1.1 m to 2.1 m below the existing

grade. The sandy silt fill contained rock fragments, trace to some clay, trace gravel, rootles

and organic matter. Water contents for the sandy silt fill ranged from 4 % and 12 %.

3.1.3 Silty Clay

Native brown to grey silty clay was found below the sandy silt fill at Boreholes BH 17-2,

BH 17-3, BH 17-7 and BH 17-8; and extended to depths varying between 1.7 m and 2.6 m

below the existing grade. The silty clay contained some sand and trace gravel.

SPT ‘N’ values for the silty clay were ranged from 16 blows per 0.3 m to higher than 25

blows per 0.05 m (very stiff to hard in consistency), and its water contents ranged from 4

% to 9 %.

Grain size distribution and Atterberg Limits for the silty and clay are shown on Record

of Boreholes and in Appendix B, and summarized in Table 3.1.

Table 3.1 – Results of Laboratory Testing (Silty Clay)

Location Borehole

No

Sample

No.

Depth

(m)

Grain Size Distribution Atterberg Limits

Gravel

(%)

Sand

(%)

Silt

(%)

Clay

(%)

Liquid

Limit

Plastic

Limit

Plasticity

Index

Bridge B BH 17-2 SS 4 2.3 – 2.5 2 15 47 36 38 19 19

Bridge B BH 17-3 SS 4 1.5 – 1.6 0 18 48 34 35 17 18

Bridge E BH 17-7 SS 4 1.5 – 1.8 3 22 50 25 33 19 14

Bridge F BH 17-8 SS 4 1.5 – 2.0 1 10 59 30 39 21 18



(TT163003, dated 16 June 2016)





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3.1.4. Weathered Shale

Weathered shale of the Georgian Bay Formation, which could be augered through, was

encountered at all borehole locations below the sandy silt fill at Boreholes BH 17-1, BH

17-4 to BH 17-6 or the native silty clay at Boreholes BH 17-2, BH 17-3, BH 17-7 and BH 17-

8. The weathered shale extended to about 4.6 m below grade at Borehole BH 17-6 and to

the borehole termination depths of 1.7 m to 2.9 m at the rest of boreholes.

SPT ‘N’ values for the weathered shale ranged from 25 blow per 0.15 m to 50 blows per

0.05 m, and the water contents ranged from 4 % to 9 %.

Auger refusal was encountered within the weathered shale at all the boreholes drilled by

the Minute Man. The auger refusal could be due to the presence of sound shale bedrock.

3.1.5. Shale Bedrock

Shale bedrock was found at 4.6 m below grade at Borehole BH 17-6 location. Auger

refusal occurred at the termination depth of 4.7 m below the existing grade.

3.2 Groundwater Conditions

Groundwater was encountered at 0.9 m and 4.6 m below grade at BH 17-5 and BH 17-6,

respectively, upon completion of drilling. The remaining boreholes were dry.

It should be noted that groundwater level can fluctuate and can be higher during spring

months, precipitation and/or high creek water levels.

4.0 DISCUSSIONS AND RECOMMENDATIONS

The subsurface soil conditions at the proposed temporary bridge locations are provided

in this letter report, together with discussion and recommendations for bridge

foundations. General discussion and recommendations of geotechnical and



(TT163003, dated 16 June 2016)





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Table 2.1 – Maintenance Hole Elevations

Maintenance

Hole No. Location

Geodetic

The coordinates and geodetic elevations for the boreholes are shown on the Record of

Boreholes and summarized in Table 2.2.

Table 2.2 – Borehole Locations

Borehole

No.

Drilling Date Borehole

Depth (m)

NAD 27 Geodetic

Ground

Elevation (m) From To Easting Northing

BH 17-1 Sep.29, 17 Oct. 19, 17 1.7 304284 4832884 101.1

BH 17-2 Sep. 29, 2017 2.9 304336 4832794 100.3

BH 17-3 Oct. 10, 17 Oct. 12, 17 1.9 304371 4832759 99.3

BH 17-4 Oct. 6, 17 Oct. 19, 17 2.3 304468 4832650 97.7

BH 17-5 Oct. 6, 17 1.7 304502 4832573 95.6

BH 17-6 Oct. 13, 17 4.7 304765 4832433 92.7

BH 17-7 Oct. 5, 17 2.2 304785 4832395 93.7

BH 17-8 Oct. 5, 17 2.6 304871 4832277 92.4

Elevation (m)

MH 322-025-1 Bridge A location, west bank of South Mimico Creek 101.4

MH 322-024-1 Bridge B location, west bank of South Mimico Creek 100.9

MH 322-023-1 Bridge B location, east bank of South Mimico Creek 99.6

MH 322-021-1 Bridge C location, west bank of South Mimico Creek 98.0

MH 322-019-1 Bridge D location, east bank of South Mimico Creek 96.0

MH 322-017-1 Bridge E location, east bank of South Mimico Creek 94.6

MH 322-016-1 Bridge E location, west bank of South Mimico Creek 94.0

MH 322-014-1 Bridge F location, west bank of South Mimico Creek 92.6



(TT163003, dated 16 June 2016)





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Tel. No.: (905) 403-5014

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hydrogeological aspects for the South Mimico site provided in Amec Foster Wheeler’s

previously-submitted geotechnical investigation report titled “Geotechnical

Investigation Report, Highland Sewershed Trunk Sewer Rehabilitation, South Mimico

Site, Toronto, Ontario”, Reference No.: TT163003, dated 16 June 2016, should be

considered where applicable.

According to the information by CH2M, the proposed temporary bridges will be Acrow

Panel Bridge or equivalent with an open truss system. The bridge lengths vary from 21.4

m to 49.0 m, while the width is 3.15 m for Bridge B and 4.20 m for the rest of the bridges,

as shown on Drawing C40 to C42 in Appendix C.

Based on the soil profiles encountered, spread/strip footings founded on native silt and

clay, silty clay, or weathered shale should be capable of supporting the bridge abutment

foundations.

4.1 Foundation

Based on the soil conditions encountered in Boreholes BH 17-1 to BH 17-8, and BH 4 to BH 8, the weathered shale should be capable of supporting spread/strip footings for the proposed bridges. Due to the shallow depth of the weathered shale, the bridge footings should be founded on or within the weathered shale. The recommended geotechnical reactions / resistances for the weathered shale, according to the Canadian Highway Bridge Design Code, are summarized in Table 4.1.



(TT163003, dated 16 June 2016)





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Table 4.1 - Founding Stratum and Soil Bearing Capacity for Bridge Foundations

Bridge Reference

Borehole

Founding

Stratum

Approximate

Depth

Below Grade

(m)

Geodetic

Elevation

(m)

Geotechnical

Pressure

Reaction at

SLS

(kPa)

Factored

Geotechnical

Pressure

Resistance

(Factored ULS)*

(kPa)

A

BH 8 Weathered

shale 1.4 100.2 400 600

BH 17-1 Weathered

shale 1.2 99.9 400 600

B

BH 17-3 Weathered

shale 1.3 98.0 400 600

BH 17-2 Weathered

shale 2.1 98.2 400 600

C

BH 7 Weathered

shale 1.4 100.2 400 600

BH 17-4 Weathered

shale 2.0 95.7 400 600

D

BH 6 Weathered

shale 1.4 96.7 400 600

BH 17-5 Weathered

shale 1.4 94.2 400 600

E

BH 17-6 Weathered

shale 1.2 91.5 400 600

BH 17-7 Weathered

shale 1.1 92.6 400 600

F

BH 4 Weathered

shale 2.5 90.1 400 600

BH 17-8 Weathered

shale 1.4 90.9 400 600

Note: * A resistance factor of Φ = 0.5 has been applied to the Ultimate Limit State (ULS) values

provided.



(TT163003, dated 16 June 2016)





50 Vogell Road


Canada

Tel. No.: (905) 403-5014

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Engineered fill, if used, should be constructed as mentioned in the 2016 report and

designed with a SLS value of 150 kPa and a factored ULS value of 225 kPa.

The Serviceability Limit State (SLS) bearing values correspond to settlements of up to

25 mm.

In order to achieve the SLS/ULS soil bearing pressures provided in Table 4.1, the exposed

subgrade should be free of loose/soft, disturbed wet or otherwise deleterious materials.

The subgrade should be inspected and evaluated by a Geotechnical Engineer to confirm

that the proposed footings are founded on the competent subgrade which is capable of

the design loads. The exposed subgrade should not be disturbed by construction

activities.

4.2 Earthquake Considerations

In conformance with the criteria in Table 4.1, Section 4 of the Canadian Highway Bridge

Design Code (S6-14) from CSA on 16 February 2015, the project site should be classified

as Site Class C – “Very Dense Soil and Soft Rock”.

4.3 Slope Stability of Creek Bank

The South Mimico Creek meandered on the study site and generally drained

southbound. Along the creek, bank erosion was observed at several locations as

evidenced by the exposed soil surface and shale outcrop. The creek water level was about

0.2 m to 0.8 m deep during the field investigation, and the photographs for the bridge

profiles are provided in Appendix D.

A total of seven (7) slope stability analyses were conducted with respect to the proposed

temporary Bridge A to F locations, as per the site conditions. The analytical model, as

shown in Figure Nos. 3 to 16, considered a 1.5 m wide bridge footing founded on granular

“A” pad (if necessary), or the weathered shale with a bearing pressure of 400 kPa (SLS

value). A surcharge of 16 kPa was applied on the bridge approach to represent traffic



(TT163003, dated 16 June 2016)





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load according to the Canadian Highway Bridge Design Code. In addition, a small soil

ramp to the bridge abutment was included. The bridge foundation was located about 3.5

m from the top of the slope according to CH2M's drawings in Appendix C.

Slope stability analyses were carried out using the software package GeoStudio

SLOPE/W (Version 7.17) produced by GEO-SLOPE International Limited, employing the

Morgenstern-Price method of analyses with circular slip surfaces. The weathered shale

was considered conservatively as soil through which circular slip surfaces were

applicable.

The following conservative soil parameters were considered for the slope stability

analyses, as shown in Table 4.2.

Table 4.2 - Geotechnical Parameters for Slope Stability Analyses

Soil Type

Unit Weight: γ Effective Stress Analysis

(kN/m3) Cohesion: c’

(kPa)

Friction Angle: ’

(°)

Foundation 24 200* 0

Engineered Fill (slope grade) 21 0 30

Gravel (staging area) 21 0 30

Granular “A” Pad 21 0 30

Sandy Silt/Silty Sand Fill 18 0 28

Sandy Silt / Silty Sand 18 0 28

Silty Clay / Clayey Silt Fill 19 20 5

Silty Clay 19 25 5

Weathered Shale 22 25 30



(TT163003, dated 16 June 2016)





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Two cases were considered - one with measured groundwater level and with dry creek

(Figure Nos. 3 to 9) and the other with a groundwater level at 2 year flood line and with

rapid drawdown from 2 year flood line (Figure Nos. 10 to 16). As the creek bottom was

not shown in CH2M’ drawings, the creek bottom was assumed 0.5 m below the creek

water surface in the analyses. The calculated minimum factors of safety for the two cases

are summarized in Table 4.3.

Table 4.3 - Calculated Minimum Safety Factor against Slope Instability

Case of Analysis Figure

No. Location

Corresponding

Borehole

Groundwater

Elevation (m)

Factor of

Safety

Measured

groundwater

level and dry

creek

3 Bridge A (east bank) BH 8 – 1.89

4 Bridge A (west bank) BH 17-1 – 1.73

5 Bridge B (west bank) BH 17-2 – 1.76

6 Bridge C (east bank) BH 7 98.6 1.71

7 Bridge D (west bank) BH 6 97.0 1.53

8 Bridge E (east bank) BH 17-7 – 2.18

9 Bridge F (west bank) BH 4 - 2.15

Groundwater

level at 2 year

flood line and

rapid drawdown

of creek

10 Bridge A (east bank) BH 8 101.2 1.65

11 Bridge A (west bank) BH 17-1 101.2 1.58

12 Bridge B (west bank) BH 17-2 99.0 1.59

13 Bridge C (east bank)* BH 7 97.5 1.74

14 Bridge D (west bank)* BH 6 95.9 1.65

15 Bridge E (east bank) BH 17-7 93.0 1.90

16 Bridge F (west bank) BH 4 90.3 1.99

Note: * 2 year flood line is lower than the measured groundwater level



(TT163003, dated 16 June 2016)





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Tel. No.: (905) 403-5014

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According to Ontario Ministry of Natural Resources (MNR) “Technical Guide – River

and Stream Systems: Erosion Hazard Limit”, the common range of minimum Factor of

Safety is 1.2 to 1.5 for slope stability analysis. The slope stability analysis results

presented in Table 4.3 indicate that the proposed bridge footings founded on weathered

shale and located at least 3.5 m from the eroded creek bank (Drawing C40 to C42) should

be stable against slope instability since the minimum calculated factor of safety is 1.53 at

proposed Bridge B location under high groundwater level and 2 year flood line of the

creek. The rest of slope stability analyses performed should meet the MNR requirement

for 'a study using accepted geotechnical and engineering principles'.

It should be noted that the bank erosion was observed at the west bank of the proposed

Bridge B location (BH 17-2 location), the bank itself is not stable and could be eroded

further. The foundation for the proposed bridges should not impose any additional

loading onto the existing slopes (creek banks) between the bridge foundations and the

existing creek banks. The eroded banks should be protected against further erosion

during the bridge construction as a precaution.

As mentioned earlier, the actual width of the bridge footing depends on the actual bridge

loading and structural design which are not known at the time of this slope stability

analysis. Should the bridge footing width and location be significantly different from

those shown in the analysis (Figure Nos. 3 to 14), a new slope stability analysis may be

required.

4.4 Recommendations for Proposed Bridge Foundations

The bridge foundation founded on weathered shale should be stable against slope

instability if it is located at least 3.5 m from the top of bank slope as shown in CH2M's

drawings in Appendix C. All creek banks should be protected against creek erosion as

required by Ontario Ministry of Natural Resources (MNR) “Technical Guide – River and

Stream Systems: Erosion Hazard Limit”.

As a summary, the following recommendations should be considered in designing the

foundations for the proposed bridges:



(TT163003, dated 16 June 2016)





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a. Found the bridge footings on the weathered shale, native silty clay or granular

“A” pad at a minimum distance of 3.5 m from the crest of the creek bank. Design

the footing with the SLS value of 400 kPa such than all vertical and horizontal

loads are supported by the weathered shale (e.g., footing with load eccentricity),

or SLS value of 150 kPa by the native silty clay /silt and clay without imposing

any additional load onto the existing creek bank within the 3.5 m distance.

b. Alternatively, as planned by CH2M (Drawing C40 to C42 in Appendix C), replace

the incompetent existing fill with engineered fill (compacted Granular 'A' pad)

with the following considerations:

Place the Granular 'A' pad at a minimum distance of 3.5 m from the crest of

the creek bank.

The width of the Granular 'A' pad should extend at least 0.5 m from the

edges of the footing.

No additional fill and surcharge loads should be placed between the

Granular 'A' pad and the existing creek bank.

Design the footing with a SLS value of 150 kPa such than all vertical and

horizontal loads are supported by the Granular 'A' pad and the weathered

shale without imposing any additional load onto the existing creek bank

within the 3.5 m distance.

If the bridge footing is placed on the Granular 'A' pad without being

covered by a minimum 1.2 m thick soil, the bridge footing may undergo

movement due to freezing and thawing.

5.0 CLOSURE

This report should be read in conjunction with Amec Foster Wheeler’s previously-

submitted geotechnical investigation report “Geotechnical Investigation Report,

Highland Sewershed Trunk Sewer Rehabilitation, South Mimico Site, Toronto, Ontario”,

Reference No.: TT163003, dated 16 June 2016.



(TT163003, dated 16 June 2016)





50 Vogell Road


Canada

Tel. No.: (905) 403-5014

amecfw.com

Linda Ji, M.Sc., P. Eng., P. Geo. Prapote Boonsinsuk, Ph.D., P. Eng.

Project Manager/Geotechnical Engineer Principal Geotechnical Engineer

This report has been prepared by Linda Ji, M. Sc., P. Eng. and P. Geo., and reviewed by

Prapote Boonsinsuk, Ph.D., P. Eng.

The Report Limitations included in the 2016 report are an integral part of this report.

Sincerely,

Amec Foster Wheeler Environment & Infrastructure,

a Division of Amec Foster Wheeler Americas Limited

FIGURES

REV. NO.:

A

DATE:

OCTOBER 2017

PROJECT NO:

TT163003.9000

FIGURE No.

1

N.T.S. -

PROJECTION:

-

DATUM:

DWN BY:

CHK'D BY:

SCALE:

WJ

KW

SITE LOCATION PLAN

PROJECT

TITLE


CLIENT LOGOCLIENT


104 Crockford Boulevard, Scarborough, ON, M1R 3C3

CH2M HILL

Canada Limited

N

Bridge 'A'

Bridge 'B'

Bridge 'C'

Bridge 'D'

Bridge 'E'

Bridge 'F'

SITE

ADDENDUM TO GEOTECHNICAL INVESTIGATION REPORT



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Road Park

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MH322-025-1

MH322-024-1

MH322-023-1

MH322-021-1

MH322-019-1

MH322-017-1

MH322-016-1

MH322-014-1

TEMPORARY

BRIDGE 'E'

TEMPORARY

BRIDGE 'D'

TEMPORARY

BRIDGE 'C'

TEMPORARY

BRIDGE 'B'

TEMPORARY

BRIDGE 'A'

TEMPORARY

BRIDGE 'F'

MH322-026-1

BH 8

BH 7

BH 6

BH 4

0 100 200m

APPROXIMATE SCALE

REV. NO.:

A

DATE:

OCTOBER 2017

PROJECT NO:

TT163003.9000

FIGURE No.

2

AS SHOWN -

PROJECTION:

-

DATUM:

DWN BY:

CHK'D BY:

SCALE:

WJ

KW

BOREHOLE LOCATION PLAN

PROJECT

TITLE

ADDENDUM TO GEOTECHNICAL INVESTIGATION REPORT




CLIENT LOGOCLIENT


104 Crockford Boulevard, Scarborough, ON, M1R 3C3

CH2M HILL

Canada Limited

N

50 150

LEGEND

BOREHOLE LOCATION

BOREHOLE LOCATION (2016 Investigation)

EXISTING SEWER

1.89

Weathered Shale

Silty Sand Fill

GravelEngineered Fill

Foundation

Silty Sand Fill

Bearing Pressure = 400 kPa

Figure No. 3 Slope Stability Analysis for Proposed Temporary Bridge A (East Bank)

Measured Groundwater Level with Dry Creek

Surcharge: 16 kPa

Sandy Silt

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3094.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Name: Foundation Unit Weight: 24 kN/m³ Cohesion: 200 kPa Phi: 0 °

Name: Gravel Unit Weight: 21 kN/m³ Cohesion: 0 kPa Phi: 30 °

Name: Silty Sand Fill Unit Weight: 18 kN/m³ Cohesion: 0 kPa Phi: 28 °

Name: Sandy Silt Unit Weight: 18 kN/m³ Cohesion: 0 kPa Phi: 28 °

Name: Wheathered Shale Unit Weight: 22 kN/m³ Cohesion: 25 kPa Phi: 30 °

Name: Engineered Fill Unit Weight: 21 kN/m³ Cohesion: 0 kPa Phi: 30 °

CH2M HILLCanada Limited

Addendum Geotechnical Investigation Report

Proposed Temporary Bridge A, BH 8 Location

Highland Sewershed Trunk Sewer Rehabilitation, South Mimico Site

Amec Foster Wheeler Reference Number: TT163003.9000

1.73

Weathered Shale

Sandy Silt Fill Sandy Silt Fill


Foundation


Figure No. 4 Slope Stability Analysis for Proposed Temporary Bridge A (West Bank)

Measured Goundwater Level with Dry Creek

Surcharcge: 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3095.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0



Proposed Temporary Bridge A, BH 17-1 Location





Name: Weathered Shale Unit Weight: 22 kN/m³ Cohesion: 25 kPa Phi: 30 °


Name: Sandy Silt Fill Unit Weight: 18 kN/m³ Cohesion: 0 kPa Phi: 28 °

1.76

Weathered Shale

Silty Clay

Sandy Silt Fill

Gravel Engineered Fill

Foundation

Sandy Silt Fill

Bearing Pressure = 400kPa

Silty Clay

Figure No. 5 Slope Stability Analysis for Proposed Temporary Bridge B (West Bank)


Surcharge = 16kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3093.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

Ele

va

tio

n

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0




Name: Silty Clay Unit Weight: 19 kN/m³ Cohesion: 25 kPa Phi: 5 °





Proposed Temporary Bridge B, BH 17-2 Location



1.71

Silty Clay

Weathered Shale







Figure No. 6 Slope Stability Analysis for Proposed Temporary Bridge C (East Bank)


Engineered FillFoundation


Surcharge = 16 kPa

Gravel

Distance

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 3495.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0



Proposed Temporary Bridge C, BH 7 Location



1.53

Weathered Shale

GravelSilty Clay/Clayey Silt Fill


Figure No. 7 Slope Stability Analysis for Proposed Temporary Bridge D (West Bank)



Surcharge = 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 2891.0

92.0

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

Ele

va

tio

n

91.0

92.0

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0



Proposed Temporary Bridge D, BH 6 Location







Name: Silty Clay / Clayey Silt Fill Unit Weight: 19 kN/m³ Cohesion: 20 kPa Phi: 5 °

2.18

Weathered Shale

Silty Clay


GravelEngineered FillFoundation







Name: Amourstone Cover Unit Weight: 24 kN/m³ Cohesion: 25 kPa Phi: 30 °


Silty Clay

Figure No. 8 Slope Stability Analysis for Proposed Temporary Bridge E (West Bank)

Measured Goundwater Level with Dry Creek

Amourstone Cover

Surcharcge: 16 kPa

Distance

-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 2287.0

87.5

88.0

88.5

89.0

89.5

90.0

90.5

91.0

91.5

92.0

92.5

93.0

93.5

94.0

94.5

95.0

95.5

96.0

Ele

va

tio

n

87.0

87.5

88.0

88.5

89.0

89.5

90.0

90.5

91.0

91.5

92.0

92.5

93.0

93.5

94.0

94.5

95.0

95.5

96.0



Proposed Temporary Bridge E, BH 17-7 Location



2.15

Weathered Shale

Silty Clay/Clayey Silt Fill

Gravel









Figure No. 9 Slope Stability Analysis for Proposed Temporary Bridge F (West Bank)


Surcharge = 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3085.0

86.0

87.0

88.0

89.0

90.0

91.0

92.0

93.0

94.0

Ele

va

tio

n

85.0

86.0

87.0

88.0

89.0

90.0

91.0

92.0

93.0

94.0



Proposed Temporary Bridge F, BH 4 Location



1.65

Figure No. 10 Slope Stability Analysis for Proposed Temporary Bridge A (East Bank)

Groundwater Level at 2 Year Flood Line with Rapid Drawdown of Creek Water Level

Weathered Shale



Name: Silty Sand Fill Unit Weight: 18 kN/m³ Cohesion: 0 kPa Phi: 28 °




Silty Sand Fill


Foundation

Silty Sand Fill


Surcharge: 16 kPa

Sandy Silt

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3094.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0



Proposed Temporary Bridge A, BH 8 Location



1.58

Weathered Shale


Gravel

Figure No. 11 Slope Stability Analysis for Proposed Temporary Bridge A (West Bank)




Surcharcge: 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3095.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0



Proposed Temporary Bridge A, BH 17-1 Location








1.59

Figure No. 12 Slope Stability Analysis for Proposed Temporary Bridge B (West Bank)

Groundwater Level at 2 Year Flood Line with Repid Drawdown of Creek Water Level

Weathered Shale

Silty Clay

Sandy Silt Fill

Gravel Engineered Fill

Foundation

Sandy Silt Fill


Silty Clay

Surcharge = 16kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3093.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

Ele

va

tio

n

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0









Proposed Temporary Bridge B, BH 17-2 Location



1.74

Figure No. 13 Slope Stability Analysis for Proposed Temporary Bridge C (East bank)

Groundwater Level at 2 Year Flood Line with Repid Drawdown of Creek Water Level

Silty Clay

Weathered Shale



Surcharge = 16 kPa

Gravel

Distance

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 3495.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0

Ele

va

tio

n

95.0

96.0

97.0

98.0

99.0

100.0

101.0

102.0

103.0

104.0



Proposed Temporary Bridge C, BH 7 Location









1.65

Weathered Shale

Figure No. 14 Slope Stability Analysis for Proposed Temporary Bridge D (West Bank)


GravelSilty Clay/Clayey Silt Fill



Surcharge = 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 2891.0

92.0

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0

Ele

va

tio

n

91.0

92.0

93.0

94.0

95.0

96.0

97.0

98.0

99.0

100.0



Proposed Temporary Bridge D, BH 6 Location








1.90

Weathered Shale

Silty Clay


Gravel

Figure No. 15 Slope Stability Analysis for Proposed Temporary Bridge E (West Bank)









Name: Amourstone Cover Unit Weight: 24 kN/m³ Cohesion: 25 kPa Phi: 30 °


Silty Clay

Surcharcge: 16 kPa

Amourstone Cover

Distance

-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 2287.0

87.5

88.0

88.5

89.0

89.5

90.0

90.5

91.0

91.5

92.0

92.5

93.0

93.5

94.0

94.5

95.0

95.5

96.0

Ele

va

tio

n

87.0

87.5

88.0

88.5

89.0

89.5

90.0

90.5

91.0

91.5

92.0

92.5

93.0

93.5

94.0

94.5

95.0

95.5

96.0



Proposed Temporary Bridge E, BH 17-7 Location



1.99

Weathered Shale

Figure No. 16 Slope Stability Analysis for Proposed Temporary Bridge F (West Bank)




Foundation


Bearing Pressure = 400 kPa Surcharge = 16 kPa

Distance

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 3085.0

86.0

87.0

88.0

89.0

90.0

91.0

92.0

93.0

94.0

Ele

va

tio

n

85.0

86.0

87.0

88.0

89.0

90.0

91.0

92.0

93.0

94.0



Proposed Temporary Bridge F, BH 4 Location








RECORD OF BOREHOLES

Documents

20 December 2017 Amec Foster Wheeler Reference No.: TT163003 · of track mounted rig and Minute Man (hand-operated rig) equipped with solid stem augers. As the Minute Man was not