Appendix H. Geotechnical Investigation Report. Krosno Creek Flood Reduction Project PROJECT FILE REPORT CITY OF PICKERING

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1 Krosno Creek Flood Reduction Project PROJECT FILE REPORT CITY OF PICKERING Appendix H Geotechnical Investigation Report TMIG THE MUNICIPAL INFRASTRUCTURE GROUP LTD

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3 Report on Geotechnical Investigation Proposed Replacement of Three Culverts of Krosno Creek At Morden Lane, Reytan Boulevard and Alyssum Street Pickering, Ontario Prepared For: TMIG 8800 Dufferin Street, Suite 200 Vaughan, Ontario L4K 0C5 July, SPL Consultants Limited

4 Table of Contents 1. INTRODUCTION FIELD AND LABORATORY WORK SUBSURFACE CONDITIONS Culvert at Morden Lane (BH14 1 & BH14 2) Soil Conditions Groundwater Conditions Culvert at Reytan Boulevard (BH14 & BH14 4) Soil Conditions Groundwater Conditions Culvert at Alyssum Street (BH14 5 & BH14 6) Soil Conditions Groundwater Conditions DISCUION AND RECOMMENDATIONS FOUNDATIONS Discussion on Foundation Options Recommended Culvert Foundations EARTH PREURES AND BACKFILLING SCOUR AND EROSION PROTECTION CONSTRUCTION COMMENTS FROST PROTECTION GENERAL COMMENTS AND LIMITATIONS OF REPORT July, 2014

5 Drawings Borehole Location Plan for Culvert at Morden Lane 1 Borehole Location Plan for Culvert at Reytan Boulevard 2 Borehole Location Plan for Culvert at Alyssum Street General Notes on Sample Descriptions 4 Borehole Logs 5 to 10 Gradation Curves 11 Appendix A: General Comments on Shale Bedrock July, 2014

6 1 1. INTRODUCTION SPL Consultants Limited (SPL) was retained by TMIG to carry out a geotechnical investigation for the proposed replacement of three culverts of Krosno Creek at Morden Lane, Reytan Boulevard and Alyssum Street in Pickering, Ontario. It is understood that the three existing CSP culverts will be replaced with twin m wide X 1.8m high concrete box culverts. It is also understood that there will not be any grade raise at the culvert locations / road levels. The objectives of the investigation were to determine the subsurface conditions at the locations of the proposed culverts by means of exploratory boreholes, and to provide geotechnical recommendations for the design and construction of the new culvert structures. This report is provided on the basis of the terms of reference presented above and on the assumption that the design will be in accordance with applicable codes and standards. If there are any changes in the design features relevant to the geotechnical analyses, or if any questions arise concerning the geotechnical aspects of the codes and standards, this office should be contacted to review the design. It may then be necessary to carry out additional borings and reporting before the recommendations of this office can be relied upon. This report has been prepared for TMIG, Durham Region and their designers. Third party use of this report without SPL Consultants Limited consent is prohibited. The limitations conditions presented in this report form an integral part of the report and they must be considered in conjunction with this report. 2. FIELD AND LABORATORY WORK The fieldwork for this project was performed in May 2014 and consisted of drilling and sampling six boreholes to depths varying from 11.1 to 12.8 m below the existing grades. The locations of the boreholes at the site are shown on the borehole location plans (Drawing Nos. 1, 2 and ). The borehole locations and depths at each culvert location are as follows: Two boreholes (BH14 1 and BH14 2) were drilled on Morden Lane to a depth of 12.m. Two boreholes (BH14 and BH14 4) were drilled on Reytan Boulevard to a depth of 12.m. Two boreholes (BH14 5 and BH14 6) were drilled on Alyssum Street to depths varying from 11.1 to 12.8 m. The borehole locations were established in the field by SPL engineering staff. Prior to drilling operations, all underground utilities were cleared at the borehole locations by representatives of the public utilities locate companies. July, 2014

7 2 Boreholes were advanced using a truck mounted drilling rig owned and operated by Drilltech of Newmarket, Ontario, under the full time supervision of technical personnel from SPL. The boreholes were advanced using solid stem augers. Samples in the boreholes were taken at frequent intervals of depth by the Standard Penetration Test method (SPT), in general accordance with ASTM D1586. The test consists of freely dropping a 6.5 kg hammer a vertical distance of 0.76 m to drive a 51 mm 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 0.0 m is recorded as the Standard Penetration Resistance or the N value of the soil which is indicative of the compactness condition of granular (or cohesionless) soils (gravels, sands and silts) or the consistency of cohesive soils (clays and clayey soils). The samples were logged in the field and returned to the SPL Consultants Limited laboratory for detailed examination by the project engineer and for laboratory testing. In situ field vane shear tests were conducted in the weak silty clay deposit as shown on the borehole logs. As well as visual examination in the laboratory, all samples were tested for moisture contents. Selected five soil samples were subjected to grain size analysis and their gradation curves are presented on Drawing 11 of this report. Selected four soil samples were subjected to Atterberg limits testing and the results are presented on the respective borehole logs. Groundwater conditions in the boreholes were observed during and on completion of drilling in the open boreholes. One monitoring well was installed at each culvert location (BH14 1, BH14 4, and BH14 5) to determine the stabilized groundwater level over a prolonged period of time. The ground surface elevations at the borehole locations were measured by SPL personnel.. SUBSURFACE CONDITIONS Details of the subsurface conditions encountered in the boreholes are presented on the borehole logs, Drawings 5 to 10. General notes on samples descriptions are presented on Drawing 4. The following description of the individual soil strata is to assist the designers of the project with an understanding of the anticipated subsurface conditions underlying the site. It should be noted that the soil and groundwater conditions may vary in between and beyond borehole locations. The summarized subsurface conditions for each culvert location are described in the following paragraphs..1 Culvert at Morden Lane (BH14 1 & BH14 2).1.1 Soil Conditions In general, below the topsoil and fill, the boreholes encountered weak silty clay deposit, overlying silty sand till, underlain by bedrock. Details of the subsurface conditions encountered in the boreholes are presented in the individual borehole logs, Drawings 5 and 6, and are briefly summarized below. July, 2014

8 Topsoil/Fill Material Topsoil layer, about 175 to 250 mm thick, was encountered in the boreholes at surface. Fill material consisting of clayey silt to silty clay was encountered in both the boreholes below topsoil, extending to a depth of 2.7m. Trace to some topsoil / organics inclusions were noted in the fill material. Fill material was present in a firm to stiff consistency, with measured SPT N values ranging from 4 to 15 blows per 00 mm of penetration. Measured moisture content in the tested fill samples ranged from 10 to 26%. Silty Clay Below the fill material in the boreholes, upper native soil consisting of silty clay was encountered, extending to depths varying from 5.0 to 5.6m. Silty clay deposit was present in a firm to stiff consistency, with measured SPT N values ranging from 2 to 10 blows per 00 mm of penetration. Measured moisture content in the tested silty clay samples ranged from 20 to 2%. As shown on the borehole logs, three () vane shear tests were conducted in the silty clay deposit, with measured undrained shear strength ranging from 5 to over 100 kpa. Two grain size analyses were carried out on the selected silty clay samples (BH14 1/5 and BH14 2/5). The results are presented on the borehole logs, and the gradation curves are presented in Drawing 11, with the following fractions: Clay: 4 to 8% Silt: 59 to 64% Sand: 2 to % Atterberg Limits tests were performed on two samples (BH14 1/5 and BH14 2/5) from the silty clay deposit. The results are shown on the borehole logs and are summarized as follows: Liquid Limit: 0 to 1% Plastic Limit: 18% Plasticity Index: 12 to 1% The soil is classified as inorganic clay of low plasticity (CL). Silty Sand Till Below the silty clay in the boreholes, silty sand till deposit was encountered, overlying shale bedrock. Silty sand till was present in a compact to very dense state, with measured SPT N values ranging from 15 to over 50 blows per 00 mm of penetration. Measured moisture content in the tested silty sand till samples ranged from 5 to 10%. A 00 mm thick silty sand layer was encountered in BH14 1 at a depth of 5.2m, above silty sand till. July, 2014

9 4 Grain size analysis was carried out on selected silty sand till sample (BH14 1/7). The results are presented on the borehole log, and the gradation curves are presented in Drawing 11, with the following fractions: Shale Bedrock Clay: 14% Silt: 9% Sand: 42% Gravel: 5% The shale bedrock was encountered in both the boreholes, at depths ranging from 11.0 to 12.2 m from the existing grade. The shale bedrock was not proven by rock core drilling. The depth and elevation of the shale bedrock surface in the boreholes are listed on Table 1 below. Borehole No. Table 1: Depth and Elevation of Shale Bedrock Surface Depth of Shale Bedrock Surface below Existing Ground (m) Approximate Elevation of Shale Bedrock Surface (m) Notes BH Augered BH Augered Commonly the till overlying the shale contains slabs of limestone which would give a false indication of the bedrock level. Similarly the depth of weathering cannot be determined accurately due to the presence of limestone layers. The shale bedrock generally contains layers of sandstone, limestone and dolostone. Typically the hard layers comprise about 10 to 20 percent of the unit. However, higher concentrations of hard layers can be present. The hard layers are usually less than 100 to 150 mm thick but some layers are much thicker. The thicker layers have been observed to be as much as 750 to 900 mm at other sites. The layers are actually lenses and they can vary significantly in thickness over short distance. Methane gas is anticipated in the bedrock. Appropriate care and monitoring is essential in all confined bedrock excavations, particularly for caissons. Stress relief features such as folds and faults are common in the shale bedrock. Appendix A presents more details and general comments about the shale bedrock..1.2 Groundwater Conditions The observed short term groundwater levels in the boreholes upon completion of drilling varied from.7 to 4.6m below the existing grade. However, the groundwater table observed in the monitoring well installed in BH14 1 was at a depth of 2.2m, corresponding to Elevation 78.1 m on June 18, July, 2014

10 5 It should be noted that the groundwater at the site would be subject to seasonal fluctuations as well as fluctuations due to weather events and the water level in the creek..2 Culvert at Reytan Boulevard (BH14 & BH14 4).2.1 Soil Conditions In general, below the topsoil and fill, the boreholes encountered weak silty clay deposit, overlying gravelly sand /sand followed by silty sand till, underlain by bedrock. Details of the subsurface conditions encountered in the boreholes are presented in the individual borehole logs, Drawings 7 and 8, and are briefly summarized below. Topsoil/Fill Material Topsoil layer, about 170 to 200 mm thick, was encountered in the boreholes at surface. Fill material consisting of clayey silt to silty clay and sandy silt was encountered in the boreholes, extending to depths varying from 2.0 to 2.8m. Trace to some topsoil / organics inclusions were noted in the fill material. Fill material was present in a firm to stiff consistency / compact state, with measured SPT N values ranging from 4 to 18 blows per 00 mm of penetration. Measured moisture content in the tested fill samples ranged from 7 to 1%. Silty Clay Below the fill material in the boreholes, upper native soil consisting of silty clay was encountered, extending to depths varying from 7.6 to 9.4m. Silty clay deposit was present in a firm to very stiff, generally in firm to stiff consistency, with measured SPT N values ranging from 2 to 2 blows per 00 mm of penetration. Measured moisture content in the tested silty clay samples ranged from 16 to 6%. As shown on the borehole logs, four (4) vane shear tests were conducted in the silty clay deposit, with measured undrained shear strength ranging from 0 to over 100 kpa. Grain size analysis was carried out on a selected silty clay sample (BH14 /6). The results are presented on the borehole log, and the gradation curves are presented in Drawing 11, with the following fractions: Clay: 41% Silt: 58% Sand: 1% Atterberg Limits test was performed on the same silty clay sample (BH14 /6). The results are shown on the borehole log and are summarized as follows: Liquid Limit: 29% Plastic Limit: 17% Plasticity Index: 12% July, 2014

11 6 The soil is classified as inorganic clay of low plasticity (CL). Gravelly Sand/ Sand: A 900 mm thick gravelly sand layer was encountered in BH14 at a depth of 7.6m, above silty sand till. Sand layer about 1.m was encountered in BH14 4 below silty clay and overlying silty sand till. Gravelly sand / sand were water bearing and present in a very loose to compact state. Grain size analysis was carried out on gravelly sand sample (BH14 /8 top portion). The results are presented on the borehole log, and the gradation curve is presented in Drawing 11, with the following fractions: Silty Sand Till Clay: 5% Silt: 17% Sand: 52% Gravel: 26% Below the gravelly sand or sand in the boreholes, silty sand till deposit was encountered extending to a depth of about 12.2m, overlying the shale bedrock in BH14 and clayey silt in BH14 4. Silty sand till was present in a dense to very dense state, with measured SPT N values ranging from 0 to over 50 blows per 00 mm of penetration. Measured moisture content in the tested silty sand till samples ranged from 8 to 12%. Shale Bedrock The shale bedrock was encountered in BH14 at a depth of 12.2m below the existing grade, corresponding to Elevation 66.6m. The shale bedrock was not proven by rock core drilling. Commonly the till overlying the shale contains slabs of limestone which would give a false indication of the bedrock level. Similarly the depth of weathering cannot be determined accurately due to the presence of limestone layers. The shale bedrock generally contains layers of sandstone, limestone and dolostone. Typically the hard layers comprise about 10 to 20 percent of the unit. However, higher concentrations of hard layers can be present. The hard layers are usually less than 100 to 150 mm thick but some layers are much thicker. The thicker layers have been observed to be as much as 750 to 900 mm at other sites. The layers are actually lenses and they can vary significantly in thickness over short distance. Methane gas is anticipated in the bedrock. Appropriate care and monitoring is essential in all confined bedrock excavations, particularly for caissons. Stress relief features such as folds and faults are common in the shale bedrock. Appendix A presents more details and general comments about the shale bedrock. July, 2014

12 7.2.2 Groundwater Conditions The observed short term groundwater levels in the boreholes upon completion of drilling varied from 2.7 to 4.m depth. The stabilized groundwater table observed in the monitoring well installed in BH14 4 was at a depth of 1.m, corresponding to Elevation 77.7 m on June 18, It should be noted that the groundwater at the site would be subject to seasonal fluctuations as well as fluctuations due to weather events and the water level in the creek.. Culvert at Alyssum Street (BH14 5 & BH14 6)..1 Soil Conditions In general, below the topsoil and fill, the boreholes encountered weak silty clay deposit, overlying silty sand / silty sand till, underlain by bedrock. Details of the subsurface conditions encountered in the boreholes are presented in the individual borehole logs, Drawings 9 and 10, and are briefly summarized below. Topsoil/Fill Material Topsoil layer, about 100 to 180 mm thick, was encountered in boreholes at the surface. Fill material consisting of clayey silt to silty clay was encountered in both the boreholes, extending to a depth of 2.6m. Trace topsoil / organics inclusions were noted in the fill material. Fill material was present in a firm to stiff consistency, with measured SPT N values ranging from 4 to 15 blows per 00 mm of penetration. Measured moisture content in the tested fill samples ranged from 9 to 2%. Clayey Silt to Silty Clay Below the fill material in the boreholes, upper native soil consisting of clayey silt to silty clay was encountered in both the boreholes, extending to depths varying from 9.1 to 9.5m. Clayey silt to silty clay was present in a soft to stiff consistency, with measured SPT N values ranging from 2 to 15 blows per 00 mm of penetration. Measured moisture content in the tested clayey silt to silty clay samples ranged from 17 to 47%. As shown on the borehole log, a vane shear test was conducted in the silty clay deposit, with measured undrained shear strength of 46 kpa. Grain size analysis was carried out on selected clayey silt to silty clay sample (BH14 5/6). The results are presented on the borehole log, and the gradation curve is presented in Drawing 10, with the following fractions: Clay: 2% Silt: 75% Sand: 2% July, 2014

13 8 Atterberg Limits test was performed on the same sample (BH14 5/6) from the clayey silt to silty clay deposit. The results are shown on the borehole log and are summarized as follows: Liquid Limit: 20% Plastic Limit: 14% Plasticity Index: 6% The soil is classified as inorganic clayey silt of low plasticity (CL ML). Silty Sand Below the clayey silt to silty clay in the boreholes, a silty sand layer was encountered, overlying silty sand till. Silty sand was water bearing and present in a loose to very dense state, with measured SPT N values ranging from 6 to over 50 blows per 00 mm of penetration. Measured moisture content in the tested silty sand samples ranged from 10 to 12%. Silty Sand Till Silty sand till deposit was encountered in both the boreholes below silty sand, extending to the maximum explored depths. This deposit was present in a very dense state, with measured SPT N values of over 50 blows per 00 mm of penetration. Measured moisture content in the tested silty sand till samples ranged from 5 to 7%...2 Groundwater Conditions The observed short term groundwater levels in the boreholes upon completion of drilling varied from.7 to 4.6m depth. The stabilized groundwater table observed in the monitoring well installed in BH14 5 was at a depth of 1.1m, corresponding to Elevation 77.1 m on June 18, It should be noted that the groundwater at the site would be subject to seasonal fluctuations as well as fluctuations due to weather events and the water level in the creek. 4. DISCUION AND RECOMMENDATIONS It is understood that the three existing CSP culverts will be replaced with twin m wide X 1.8m high concrete box culverts. It is also understood that there will not be any grade raise at the culvert locations and road levels will remain same as the present levels. At the culvert locations, the creek beds are generally 2.5 to m below the top of the road level. Proposed founding/invert elevations of the box culverts are presented Table 2. The traditional footing types for the concrete culverts are either open box, founded on native soil base by narrow strip footings, or closed box with an integral concrete base acting as the footing. As the culvert structures will be underlain by compressible soils, a closed box culvert is considered more appropriate in comparison to open box, in terms of its ability to tolerate more differential settlements. July, 2014

14 9 4.1 FOUNDATIONS Based on the subsurface conditions explored in the boreholes, geotechnical comments and recommendations for the culvert foundations are presented as follows Discussion on Foundation Options Similar soil conditions were encountered in the boreholes at locations of the three culverts. The native soils below some fill materials generally consisted of a layer of relatively weak (firm to stiff) silty clay, overlying sandy deposits (generally silty sand). In BH14 1 to BH14 4, shale bedrock was encountered at depths of 11 to 12 m. The groundwater table was generally at about 1 to 2 m below the existing grade. Based on the soil and groundwater conditions explored at the site, the following foundation options can be considered: Option 1: Shallow foundations (footings and/or mat foundations) Option 2: Deep foundations (Driven piles) Drilled caissons are not recommended for supporting the culverts, due to the presence of saturated sand deposits between the silty clay deposit and the shale bedrock. Footings (Option 1) can be adopted for supporting the culverts, to be founded on the undisturbed silty clay deposit. The increased loading conditions from the concrete culvert structures will lead to the longterm (post construction) consolidation settlements of the underlying weak silty clay soils. The estimated total consolidation settlements of the weak silty clay encountered in the boreholes ranges from 0 to 50mm for the proposed culverts. In this case, the culverts will settle together with the approach fill. The differential settlement between the road surface over the culvert and the road surface adjacent to and beyond the culvert will be minimized. This magnitude of settlements should be tolerable for the proposed concrete culverts. More flexible CSP culverts can also be considered to better accommodate the anticipated settlement. Another way to reduce the post construction settlement of the culverts is to adopt preloading surcharge and wick drains to consolidate the ground before paving. Simple surcharging without wick drains can take a few years for the settlement to occur and may not be practical. Soil consolidation using wick drains can rapidly increase settlement rates and reduce the project durations drastically. SPL can provide detailed recommendations for preloading and wick drains, if required. Driven piles (Option 2) founded in the very dense sand deposit or shale bedrock. However, this option is not preferred, mainly due to the concerns of high costs for the construction of the piles and the pile caps. In addition, the post construction settlement of the culverts supported by driven will be minimal. However, the approach fill adjacent to and beyond the culvert will settle with time. The differential settlement between the road surface over the culvert and the road surface adjacent to and beyond the culvert will essentially be the settlement of the approach fill. Some long term cracking of the pavement will occur along both culvert. sides of the July, 2014

15 10 It is recommended that the proposed culverts be supported by shallow foundations (footings or mat foundations) founded on the undisturbed silty clay deposits Recommended Culvert Foundations Based on the information obtained from the boreholes, the closed bottom culverts founded on the undisturbed native firm to stiff silty clay deposit can be designed for bearing capacity values of 120 kpa at SLS and 160 kpa at ULS. The bearing values and the corresponding founding elevations at the borehole locations for each culvert location are summarized on Table 2 below. Table 2: Bearing Values and Founding Levels of Culverts Minimum Founding Culvert Bearing Bearing Depth Level At or Culvert Invert BH Founding Capacity Capacity below Below Location Elev. No. Soils at SLS at ULS Existing Elevation (m) (kpa) (kpa) Ground (m) (m) Morden BH14 1 Silty Clay ~77.5 Lane BH14 2 Silty Clay Reytan BH14 Silty Clay ~76.0 Blvd BH14 4 Silty Clay Alyssum BH14 5 Silty Clay ~75.5 Street BH14 6 Silty Clay The post construction settlement of the culverts will mainly result from the consolidations of the silty clay deposits. Foundations designed to the specified bearing capacity of 120 kpa at SLS are expected to settle less than 0 to 50 mm total and 20 to 0 mm differential. The anticipated maximum settlements of the proposed culverts are summarized on Table below. Table 2: Estimated Settlements of Culverts for Bearing Capacity of 120 kpa at SLS Approximate Max. Culvert Culvert Borehole Thickness of Max. Total Differential new culvert may consist of either: Location Invert Elev. (m) No. Founding Silty Clay (m) Settlement (mm) Settlement (mm) Morden Lane ~77.5 BH14 1, BH to m 0 20 Reytan Blvd ~76.0 BH14, BH to 6 m Alyssum BH14 5, ~75.5 Street BH to 7 m 50 0 Bedding, cover and backfill details for the new culvert should be as per MTOD Bedding for the July, 2014

16 mm of compacted Granular A or Granular B Type II; or 00 mm of compacted Granular A or Granular B Type II placed over a lean concrete working slab. If constructed properly, either bedding treatment is considered adequate from a foundations perspective. A 75 mm levelling course of additional Granular A or fine aggregate should also be provided between the bedding and the culvert. In order to minimize the potential for piping and undermining of the culvert foundations the bedding should be wrapped in a non woven geotextile which meets the requirements of OP Cover for the new culverts should be a minimum of 00 mm thick and may include either Granular A or Granular B with a maximum particle size of 75 mm (as per OP 422 and Special Provision 422S01). 4.2 EARTH PREURES AND BACKFILLING Backfilling behind culvert walls and any retaining (wing) walls should consist of granular materials in accordance with the applicable Standards. Free draining backfill materials, weepholes, etc. should be provided in order to prevent hydrostatic pressure build up. Backfilling around the culverts can consist of Granular A or Granular B material, placed in shallow lifts, not exceeding 200 mm loose thickness. Granular fill immediately below the roadway and adjacent to the culvert should be compacted to a minimum of 100% of their Standard Proctor Maximum Dry Density (SPMDD). Remaining fills may be compacted to a minimum of 98% of SPMDD. To avoid damaging or laterally dislocating it, care should be exercised for the compaction of the backfill adjacent to and immediately on top of the culvert structure and compaction equipment should be restricted in size. Computation of earth pressures acting against culvert walls, retaining walls and any wing walls should be in accordance with the Canadian Highway Bridge Design Code, (CHBDC) S6 06. For design purposes, the following properties can be assumed for backfill. Compacted Granular A or Granular B Type II Angle of Internal Friction =5 (unfactored) Unit weight = 22 kn/m Coefficient of Lateral Earth Pressure: July, 2014

17 12 Level Backfill Backfill Sloping at H:1V Backfill Sloping at 2H:1V K a =0.27 K a =0.4 K a =0.40 K b =0.5 K b =0.44 K b =0.50 K o =0.4 K o =0.56 K o =0.62 K*=0.45 K*=0.60 K*=0.66 Note: Compacted Granular B Type I Angle of Internal Friction =2 (unfactored) Unit Weight = 21 kn/m Coefficient of Lateral Earth Pressure: Level Backfill Backfill Sloping at H:1V Backfill Sloping at 2H:1V K a =0.1 K a =0.9 K a =0.47 K b =0.9 K b =0.49 K b =0.57 K o =0.47 K o =0.62 K o =0.69 K*=0.54 K*=0.68 K*=0.78 K a is the coefficient of active earth pressure K b is the backfill earth pressure coefficient for an unrestrained structure including compaction efforts K o is the coefficient of earth pressure at rest K* is the earth pressure coefficient for a soil loading a fully restrained structure and includes compaction effects These values are based on the assumption that the backfill behind the retaining structures is freedraining granular material and adequate drainage is provided. The earth pressure coefficient to be adopted will depend on whether the retaining structure is restrained or some movement can occur such that the active state of earth pressure can develop. The effect of compaction should also be taken into account in the selection of the appropriate earth pressure coefficients. The use of vibratory compaction equipment behind the culvert walls and the retaining walls should be restricted in size. 4. SCOUR AND EROSION PROTECTION Erosion and scour protection should be provided at the culvert inlet and outlet (including the slopes and sides). The erosion/scour protection should be designed by a specialist River Engineer/Scientist (as erosion and scour largely depend on the velocity of water in the watercourse and its regime) who is familiar with the findings of this report. The following are some general suggestions, considering that the subgrade could consist of erodible silty soils. July, 2014

18 1 We recommend that a concrete cut off (apron) be constructed both at the inlet and outlet to prevent seepage beneath and around the culvert. Beneath the culvert, the concrete cut off wall should extend to a suitable depth (e.g. below any possible scour depth). Consideration may also be given to an impervious seal at the inlet and outlet. At the inlet, consideration may also be given to the use of a clay seal. The purpose of the clay seal is to ensure that water flow is channeled through the culvert and does not seep through the backfill around the structure and from beneath the structure. The clay seal should therefore be continuous and typically 0.6 m thick. It should comply with the material specifications given in OP It should be extended around the culvert from at least 0.5 m above the high water level in the watercourse down to the channel bed and up the other side in a continuous manner. It should be ensured that it extends to cover all the granular backfill materials to prevent any seepage through them. Typically, the clay seal is protected by laying a 0.6 m thick rock protection over it. The clay seal would generally be extended at about 8 m beyond the inlet. At the outlet as well as at the inlet (if clay seal is not used), in addition to the concrete cut off and/or impervious seal or in conjunction with these, a 0.6 m thick rock protection, consisting typically of 00 mm size rock can be considered. This would generally be extended about 8m along the channel and the sides (to at least 0. m above high water level). A geotextile separator (non woven, Class II FOS 75 to 150 m) should be placed behind the rockfill to prevent migration of fine particles into the rockfill due to seepage pressure. A toe for the filter and rip rap protection should be provided at the edge of the lining and protective cover to key the lining into the natural ground to provide protection to erosion and scour. 4.4 CONSTRUCTION COMMENTS All excavations should be carried out in accordance with the Occupational Health and Safety Act (OHSA). The following soil classifications can be expected for temporary excavations in accordance with OHSA. Fill : Type soil above groundwater level and Type 4 soil below groundwater level. Weak Silty Clay : Type 4 Soil below groundwater level Dewatering will be required to stabilize the soil and to facilitate construction where excavations are required below the groundwater table or creek level. It is our opinion that in the silty clay deposits, the groundwater can be controlled by means of gravity drainage and strategically spaced and located filtered sumps. A system of cofferdams to cut off the water flow from creek into the excavation may be required to assist in excavation. Water must be lowered to at least 0.5 m below the lowest excavation level. July, 2014

19 14 Possible large obstructions such as buried concrete pieces are also anticipated in the fill material. Provisions must be made in the excavation contract for the removal of possible obstructions in the fill material. Allowance should be made to place a skim coat of concrete (mud slab) once the excavation is completed, inspected and approved, without any delay. It is recommended that the joints of the pre cast concrete box culvert be wrapped with 2 layers of geotextile (such as Terrafix 400R or equivalent) in order to minimize any loss of fine soil through the joints. The length of the geotextile along the culvert alignment should be minimum 2.4 m, i.e. extending minimum 1.2 m beyond both sides of the joints. 4.5 FROST PROTECTION Design frost protection for the general area is 1.2 m. A permanent soil cover of at least 1.2 m or its thermal equivalent is therefore required for frost protection. In case of riprap (rock fill), only one half of the rock fill thickness should be assumed to be effective in providing frost protection. 5. GENERAL COMMENTS AND LIMITATIONS OF REPORT SPL Consultants Limited should be retained for a general review of the final design and specifications to verify that this report has been properly interpreted and implemented. If not accorded the privilege of making this review, SPL Consultants Limited will assume no responsibility for interpretation of the recommendations in the report. The comments given in this report are intended only for the guidance of design engineers. The number of boreholes required to determine the localized underground conditions between boreholes affecting construction costs, techniques, sequencing, equipment, scheduling, etc., would be much greater than has been carried out for design purposes. Contractors bidding on or undertaking the works should, in this light, decide on their own investigations, as well as their own interpretations of the factual borehole and test pit results, so that they may draw their own conclusions as to how the subsurface conditions may affect them. This report is intended solely for the Client named. The material in it reflects our best judgment in light of the information available to SPL Consultants Limited at the time of preparation. Unless otherwise agreed in writing by SPL Consultants Limited, it shall not be used to express or imply warranty as to the fitness of the property for a particular purpose. No portion of this report may be used as a separate entity, it is written to be read in its entirety. The conclusions and recommendations given in this report are based on information determined at the test hole locations. The information contained herein in no way reflects on the environment aspects of the project, unless otherwise stated. Subsurface and groundwater conditions between and beyond the test holes may differ from those encountered at the test hole locations, and conditions may become apparent during construction, which could not be detected or anticipated at the time of the site July, 2014

20 15 investigation. The benchmark and elevations used in this report are primarily to establish relative elevation differences between the test hole locations and should not be used for other purposes, such as grading, excavating, planning, development, etc. The comments made in this report on potential construction problems and possible methods are intended only for the guidance of the designer. The number of test holes may not be sufficient to determine all the factors that may affect construction methods and costs. For example, the thickness of surficial topsoil or fill layers may vary markedly and unpredictably. The contractors bidding on this project or undertaking the construction should, therefore, make their own interpretation of the factual information presented and draw their own conclusions as to how the subsurface conditions may affect their work. This work has been undertaken in accordance with normally accepted geotechnical engineering practices. 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. SPL Consultants Limited accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. We accept no responsibility for any decisions made or actions taken as a result of this report unless we are specifically advised of and participate in such action, in which case our responsibility will be as agreed to at that time. July, 2014

21 16 We trust that the information contained in this report is satisfactory. Should you have any questions, please do not hesitate to contact this office. Yours very truly, SPL Consultants Limited Alka Sangar, M. Eng., P. Eng. Fanyu Zhu, Ph. D., P. Eng. Shabbir Bandukwala, M.Eng., P. Eng. July, 2014

22 1 Drawings July, 2014

23 Key Map (only for Dwg 1) BH14 1 Site BH14 2 Client: TMIG Project No: Drawing No: 1 Drawn: PM Approved: AS Title: Borehole Location Plan - Morden Lane Date: 24-Jun-14 Scale: NTS Project: Geotechnical Investigation - Proposed Replacement of Krosno Creek Culverts, Pickering, ON Original Size: Tabloid Rev: N/A

24 Key Map (only for Dwg 2) BH14 Site BH14 4 Client: TMIG Project No: Drawing No: 2 Drawn: PM Approved: AS Title: Borehole Location Plan - Reytan Boulevard Date: 24-Jun-14 Scale: NTS Project: Geotechnical Investigation - Proposed Replacement of Krosno Creek Culverts, Pickering, ON Original Size: Tabloid Rev: N/A

25 Key Map (only for Dwg ) BH14 5 Site BH14 6 Client: TMIG Project No: Drawing No: Drawn: PM Approved: AS Title: Borehole Location Plan - Alyssum Street Date: 24-Jun-14 Scale: NTS Project: Geotechnical Investigation - Proposed Replacement of Krosno Creek Culverts, Pickering, ON Original Size: Tabloid Rev: N/A

26 Drawing 4: Notes On Sample Descriptions 1. All sample descriptions included in this report generally follow the Unified Soil Classification. Laboratory grain size analyses provided by SPL also follow the same system. Different classification systems may be used by others, such as the system by the International Society for Soil Mechanics and Foundation Engineering (IMFE). Please note that, with the exception of those samples where a grain size analysis and/or Atterberg Limits testing have been made, all samples are classified visually. Visual classification is not sufficiently accurate to provide exact grain sizing or precise differentiation between size classification systems. IMFE SOIL CLAIFICATION CLAY SILT SAND GRAVEL COBBLES BOULDERS FINE MEDIUM COARSE FINE MEDIUM COARSE FINE MEDIUM COARSE EQUIVALENT GRAIN DIAMETER IN MILLIMETRES CLAY (PLASTIC) TO FINE MEDIUM CRS. FINE COARSE SILT (NONPLASTIC) SAND GRAVEL UNIFIED SOIL CLAIFICATION 2. Fill: Where fill is designated on the borehole log it is defined as indicated by the sample recovered during the boring process. The reader is cautioned that fills are heterogeneous in nature and variable in density or degree of compaction. The borehole description may therefore not be applicable as a general description of site fill materials. All fills should be expected to contain obstruction such as wood, large concrete pieces or subsurface basements, floors, tanks, etc., none of these may have been encountered in the boreholes. Since boreholes cannot accurately define the contents of the fill, test pits are recommended to provide supplementary information. Despite the use of test pits, the heterogeneous nature of fill will leave some ambiguity as to the exact composition of the fill. Most fills contain pockets, seams, or layers of organically contaminated soil. This organic material can result in the generation of methane gas and/or significant ongoing and future settlements. Fill at this site may have been monitored for the presence of methane gas and, if so, the results are given on the borehole logs. The monitoring process does not indicate the volume of gas that can be potentially generated nor does it pinpoint the source of the gas. These readings are to advise of the presence of gas only, and a detailed study is recommended for sites where any explosive gas/methane is detected. Some fill material may be contaminated by toxic/hazardous waste that renders it unacceptable for deposition in any but designated land fill sites; unless specifically stated the fill on this site has not been tested for contaminants that may be considered toxic or hazardous. This testing and a potential hazard study can be undertaken if requested. In most residential/commercial areas undergoing reconstruction, buried oil tanks are common and are generally not detected in a conventional preliminary geotechnical site investigation.. Till: The term till on the borehole logs indicates that the material originates from a geological process associated with glaciation. Because of this geological process the till must be considered heterogeneous in composition and as such may contain pockets and/or seams of material such as sand, gravel, silt or clay. Till often contains cobbles (60 to 200 mm) or boulders (over 200 mm). Contractors may therefore encounter cobbles and boulders during excavation, even if they are not indicated by the borings. It should be appreciated that normal sampling equipment cannot differentiate the size or type of any obstruction. Because of the horizontal and vertical variability of till, the sample description may be applicable to a very limited zone; caution is therefore essential when dealing with sensitive excavations or dewatering programs in till materials. GEOTECHNICAL INVESTIGATION REPLACEMENT OF KROSNO CREEK CULVERTS, ONTARIO SPL PROJECT NO.: DATE: JULY, 2014

27 LOG OF BOREHOLE BH OF 1 PROJECT: Geotechnical Investigation-Proposed Replacement of Three Culverts CLIENT: TMIG PROJECT LOCATION: Krosno Creek - Various Streets, Pickering, ON DATUM: Geodetic BH LOCATION: Morden Lane (m) ELEV DEPTH SOIL PROFILE DESCRIPTION TOPSOIL: 250mm FILL: silty clay mixed with topsoil, trace sand, trace rootlets, trace organic, trace gravel, brown, moist, firm to stiff STRATA PLOT NUMBER 1 2 SAMPLES TYPE "N" BLOWS 0. m 4 15 GROUND WATER CONDITIONS ELEVATION Concrete DRILLING DATA Method: Solid Stem Auger Diameter: 150mm Date: May/20/2014 DYNAMIC CONE PENETRATION RESISTANCE PLOT SHEAR STRENGTH (kpa) PLASTIC LIMIT FIELD VANE UNCONFINED & Sensitivity QUICK TRIAXIAL LAB VANE WATER CONTENT (%) w P NATURAL MOISTURE CONTENT w REF. NO.: Drawing No.: 5 LIQUID LIMIT w L POCKET PEN. (Cu) (kpa) NATURAL UNIT WT (Mg/m ) REMARKS AND GRAIN SIZE DISTRIBUTION (%) GR SA SI CL grey below 2.m SILTY CLAY: trace gravel, trace sand, grey, moist, firm to stiff. SILTY SAND: trace clay, trace gravel, grey, wet, compact. SILTY SAND TILL: some clay, trace gravel, grey, moist, compact to very dense trace shale fragments below 8.2m SH VANE / 100mm W. L m Jun 18, Holeplug Sand / 50mm Screen 69 SPL SOIL LOG LOGS.GPJ SPL.GDT 4/7/ SHALE BEDROCK: weathered, blackish grey. END OF THE BOREHOLE Notes: 1) Borehole open and water level 4.6mbgs upon completion of drilling. 2) 20mm monitoring well was installed upon completion. Water Level Readings: Date W.L. Depth (m) June 18/ / initial 25mm 68 GROUNDWATER ELEVATIONS GRAPH NOTES, : Numbers refer to Sensitivity =% Strain at Failure Shallow/ Single Installation Deep/Dual Installation

28 LOG OF BOREHOLE BH OF 1 PROJECT: Geotechnical Investigation-Proposed Replacement of Three Culverts CLIENT: TMIG PROJECT LOCATION: Krosno Creek - Various Streets, Pickering, ON DATUM: Geodetic BH LOCATION: Morden Lane (m) ELEV DEPTH SOIL PROFILE DESCRIPTION TOPSOIL: 175mm FILL: clayey silt to silty clay, trace topsoil, brown, moist, stiff. STRATA PLOT NUMBER 1A 1B SAMPLES TYPE "N" BLOWS 0. m 10 GROUND WATER CONDITIONS ELEVATION 80 DRILLING DATA Method: Solid Stem Auger Diameter: 150mm Date: May/1/2014 DYNAMIC CONE PENETRATION RESISTANCE PLOT SHEAR STRENGTH (kpa) PLASTIC LIMIT FIELD VANE UNCONFINED & Sensitivity QUICK TRIAXIAL LAB VANE WATER CONTENT (%) w P NATURAL MOISTURE CONTENT w REF. NO.: Drawing No.: 6 LIQUID LIMIT w L POCKET PEN. (Cu) (kpa) NATURAL UNIT WT (Mg/m ) REMARKS AND GRAIN SIZE DISTRIBUTION (%) GR SA SI CL SILTY CLAY: trace sand, brown, very moist to wet, firm to stiff grey below.1m SILTY SAND TILL: trace to some clay, trace gravel, grey, moist, compact to very dense trace shale fragments below 9.1m VANE VANE / initial 50mm SHALE BEDROCK: weathered, blackish grey / 150mm 69 SPL SOIL LOG LOGS.GPJ SPL.GDT 4/7/ END OF THE BOREHOLE Notes: 1) Borehole open and water level.7mbgs upon completion of drilling / initial 75mm GROUNDWATER ELEVATIONS GRAPH NOTES, : Numbers refer to Sensitivity =% Strain at Failure Shallow/ Single Installation Deep/Dual Installation

29 LOG OF BOREHOLE BH14-1 OF 1 PROJECT: Geotechnical Investigation-Proposed Replacement of Three Culverts CLIENT: TMIG PROJECT LOCATION: Krosno Creek - Various Streets, Pickering, ON DATUM: Geodetic BH LOCATION: Reytan Boulevard (m) ELEV DEPTH SOIL PROFILE DESCRIPTION TOPSOIL: 200mm FILL: sandy silt, some clay, trace to some topsoil, dark brown, moist, compact trace topsoil with silty clay pockets at 0.8m FILL: silty clay, trace organics, dark brown to dark grey, moist, stiff silty sand pockets at 2.m SILTY CLAY: trace sand, brown mottled with grey, moist, firm to stiff silty seams at 4.6m GRAVELLY SAND: some silt, trace clay, grey, wet, very loose to compact SILTY SAND TILL: some gravel, trace clay, grey, wet, dense. STRATA PLOT NUMBER SAMPLES TYPE VANE SH VANE "N" BLOWS 0. m GROUND WATER CONDITIONS ELEVATION DRILLING DATA Method: Solid Stem Auger Diameter: 150mm Date: May/1/2014 DYNAMIC CONE PENETRATION RESISTANCE PLOT SHEAR STRENGTH (kpa) PLASTIC LIMIT NATURAL MOISTURE CONTENT w LIQUID LIMIT FIELD VANE UNCONFINED & Sensitivity QUICK TRIAXIAL LAB VANE WATER CONTENT (%) w P REF. NO.: Drawing No.: 7 w L POCKET PEN. (Cu) (kpa) NATURAL UNIT WT (Mg/m ) REMARKS AND GRAIN SIZE DISTRIBUTION (%) GR SA SI 1 CL SPL SOIL LOG LOGS.GPJ SPL.GDT 4/7/ SHALE BEDROCK: weathered, greyish black. END OF THE BOREHOLE Notes: 1) Borehole open and water level 2.7mbgs upon completion of drilling. 9 50/ initial 25mm 67 GROUNDWATER ELEVATIONS GRAPH NOTES, : Numbers refer to Sensitivity =% Strain at Failure Shallow/ Single Installation Deep/Dual Installation

30 LOG OF BOREHOLE BH OF 1 PROJECT: Geotechnical Investigation-Proposed Replacement of Three Culverts CLIENT: TMIG PROJECT LOCATION: Krosno Creek - Various Streets, Pickering, ON DATUM: Geodetic BH LOCATION: Reytan Boulevard (m) ELEV DEPTH SOIL PROFILE TOPSOIL: 170mm FILL: clayey silt, trace sand, trace organics, brown, moist, firm to stiff mm layer of sand SILTY CLAY: trace sand, occasional wet silt seams, brown, moist, firm to stiff. grey below.8m DESCRIPTION SAND: trace to some silt, trace gravel, grey, wet, compact SILTY SAND TILL: trace to some clay, trace gravel, grey, wet, very dense. STRATA PLOT NUMBER SAMPLES TYPE VANE VANE "N" BLOWS 0. m GROUND WATER CONDITIONS ELEVATION Cement 78 W. L m Jun 18, Bentonite Sand 70 Screen DRILLING DATA Method: Solid Stem Auger Diameter: 150mm Date: May/12/2014 DYNAMIC CONE PENETRATION RESISTANCE PLOT SHEAR STRENGTH (kpa) PLASTIC LIMIT NATURAL MOISTURE CONTENT w LIQUID LIMIT FIELD VANE UNCONFINED & Sensitivity QUICK TRIAXIAL LAB VANE WATER CONTENT (%) w P REF. NO.: Drawing No.: 8 w L POCKET PEN. (Cu) (kpa) NATURAL UNIT WT (Mg/m ) REMARKS AND GRAIN SIZE DISTRIBUTION (%) GR SA SI CL SPL SOIL LOG LOGS.GPJ SPL.GDT 4/7/ some clay, moist below 12.2m END OF THE BOREHOLE Notes: 1) Borehole cave in 11.6mbgs and water level 4.mbgs upon completion of drilling. 2) 20mm monitoring well was installed upon completion. Water Level Readings: Date W.L. Depth (m) June 18/ / initial 75mm Sand 67 GROUNDWATER ELEVATIONS GRAPH NOTES, : Numbers refer to Sensitivity =% Strain at Failure Shallow/ Single Installation Deep/Dual Installation

31 LOG OF BOREHOLE BH OF 1 PROJECT: Geotechnical Investigation-Proposed Replacement of Three Culverts CLIENT: TMIG PROJECT LOCATION: Krosno Creek - Various Streets, Pickering, ON DATUM: Geodetic BH LOCATION: Alyssum Street (m) ELEV DEPTH SOIL PROFILE DESCRIPTION TOPSOIL: 100mm FILL: clayey silt to silty clay, trace topsoil, trace gravel, brown, moist, firm to stiff mm gravelly sand layer at 0.5m CLAYEY SILT TO SILTY CLAY: trace sand, brownish grey, very moist, firm to stiff wet at.8m mm sandy silt layer at 8.2m SILTY SAND: trace clay, trace gravel, grey, wet, loose SILTY SAND TILL: trace to some clay, trace gravel, trace shale fragment, grey, moist, very dense. STRATA PLOT NUMBER 1A 1B SAMPLES TYPE SH "N" BLOWS 0. m GROUND WATER CONDITIONS ELEVATION 78 Concrete W. L m Jun 18, Holeplug DRILLING DATA Method: Solid Stem Auger Diameter: 150mm Date: May/07/2014 DYNAMIC CONE PENETRATION RESISTANCE PLOT SHEAR STRENGTH (kpa) PLASTIC LIMIT NATURAL MOISTURE CONTENT w LIQUID LIMIT FIELD VANE UNCONFINED & Sensitivity QUICK TRIAXIAL LAB VANE WATER CONTENT (%) Sand Screen w P REF. NO.: Drawing No.: 9 w L POCKET PEN. (Cu) (kpa) NATURAL UNIT WT (Mg/m ) REMARKS AND GRAIN SIZE DISTRIBUTION (%) GR SA SI 0 2 CL 75 2 SPL SOIL LOG LOGS.GPJ SPL.GDT 4/7/ END OF THE BOREHOLE Notes: 1) Borehole open and water level.7mbgs upon completion of drilling. 2) 20mm monitoring well was installed upon completion. Water Level Readings: Date W.L. Depth (m) June 18/ Sand GROUNDWATER ELEVATIONS GRAPH NOTES, : Numbers refer to Sensitivity =% Strain at Failure Shallow/ Single Installation Deep/Dual Installation