GEOTECHNICAL INVESTIGATION. Adelaide Street at Canadian Pacific Rail Underpass Mile Galt Subdivision London, Ontario

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1 GEOTECHNICAL INVESTIGATION Adelaide Street at Canadian Pacific Rail Underpass Mile Galt Subdivision London, Ontario Submitted to: Mr. Ardian Spahiu, P.Eng., Transportation Design Engineer Corporation of the City of London 300 Dufferin Avenue London, Ontario N6A 4L9 REPORT Report Number: R01 Distribution: 2 Copies - Corporation of the City of London 1 E-Copy - Golder Associates Ltd.

2 ADELAIDE STREET AT CPR UNDERPA Table of Contents 1.0 INTRODUCTION SITE DESCRIPTION SITE GEOLOGY FIELD PROCEDURES SUBSURFACE CONDITIONS Soil Conditions Groundwater DISCUION AND RECOMMENDATIONS Excavations and Groundwater Control Rail Bridge Foundations Shallow Foundations Deep Foundations CP Rail Detour Seismic Analysis Seismic Hazard Assessment Retaining Walls Lateral Earth and Water Pressures Secant Pile (Caisson) Walls Soldier-Pile and Lagging Walls Cast-in Place Concrete and R/MSE Retaining Walls Global Stability of Retaining Walls Tie-Backs/Ground Anchors Monitoring of Track Protection Retaining Walls Backfill Pavements Permanent Drainage System Additional Geotechnical Services Report No R01 i

3 ADELAIDE STREET AT CPR UNDERPA Important Information and Limitations of This Report Method of Soil Classification Abbreviations and Terms Used on Records of Boreholes and Test Pits List of Symbols Record of Boreholes FIGURES Figure 1: Figure 2: Figure 3: Location Plan Grain Size Distribution - Silty Sand Grain Size Distribution - Silt Report No R01 ii

4 ADELAIDE STREET AT CPR UNDERPA 1.0 INTRODUCTION The purpose of the work described in this report was to explore the subsurface soil and groundwater conditions at the site and to provide geotechnical engineering recommendations for design of the proposed Adelaide Street underpass and related bridge structure for the Canadian Pacific Rail (CPR) tracks. Authorization to proceed with the work described in this report, which was carried out in accordance with our proposal dated September 23, 2016 and subsequent correspondence, was provided via Purchase Order No from the Corporation of the City of London (City). Based on the preliminary information provided by the City, a new rail underpass is to be constructed on Adelaide Street at the CPR tracks between Pall Mall Street and Central Avenue. The existing Adelaide Street grade will be lowered as much as 7 metres and the proposed rail bridge will be a single or two span bridge. Important information on the limitations of this report is attached. 2.0 SITE DESCRIPTION The subject section of Adelaide Street carries four lanes of at-grade traffic across the CPR tracks between Pall Mall Street and Central Avenue in London, Ontario, as shown on the Key Plan, Figure 1. Land use in the area of the site is primarily commercial with a park located to the northeast. The ground surface topography at the site is relatively flat with ground surface elevations of about 249 metres. A profile of the proposed Adelaide Street grade lowering was provided by the City for reference. The new Adelaide Street pavement surface will be at about elevation metres at its deepest point. Detailed design information for the proposed bridge structure was not known at the time of preparing this report. 3.0 SITE GEOLOGY The site is located in the physiographic region of southwestern Ontario known as the Caradoc Sand Plains and London Annex as indicated in The Physiography of Southern Ontario, by Chapman and Putnam (1984). The area is characterized by sands or other light textured, water-laid deposits. Based on the Ontario Department of Mines Preliminary Map P.606 titled Pleistocene Geology, St. Thomas Area (East Half), Southern Ontario, the surficial soils at the bridge site consist of valley trains and deltaic deposits covered by silty sand. The site is reportedly underlain by middle Devonian-age limestone of the Dundee Formation of the Hamilton Group. Based on the Ontario Department of Mines Preliminary Map P.482 titled Bedrock Topography Series, St. Thomas Sheet, Southern Ontario, the bedrock surface is at about elevation 216 metres at the underpass site or some 33 metres below the ground surface. 4.0 FIELD PROCEDURES Field work for this investigation was carried out on November 2 and 3, 2016 during which time two boreholes, labelled BH-101 and BH-102, were drilled at the approximate locations shown on the Location Plan, Figure 1. Standard penetration testing and sampling was carried out in both of the boreholes using 38 millimetre inside diameter split spoon sampling equipment in accordance with the standard penetration test (SPT) procedures Report No R01 1

5 ADELAIDE STREET AT CPR UNDERPA (ASTM D 1586) and an automatic hammer. The soil stratigraphy encountered in the boreholes is shown in detail on the Record of Borehole sheets following the text of this report. Groundwater seepage conditions were observed in the boreholes during drilling and a temporary piezometer was installed in BH-101 as detailed on the corresponding Record of Borehole sheet. Upon completion of sampling, in situ testing and piezometer installation, the boreholes were backfilled in accordance with Ontario Regulation (O.Reg.) 903, as amended. All of the samples obtained during the investigation were transported to our London laboratory for further examination and representative classification testing. The results of the field and laboratory testing are shown on the Record of Borehole sheets and on Figures 2 and 3. The borehole locations were designated in the field by members of our engineering staff who also arranged for underground utility clearances, supervised the drilling, sampling and standard penetration testing, logged the boreholes, cared for the samples and provided temporary traffic control. The ground surface elevations at the borehole locations were surveyed by Golder Associates Ltd. (Golder) using GPS survey equipment and referenced to geodetic datum. 5.0 SUBSURFACE CONDITIONS The subsurface conditions encountered in the boreholes advanced at the site are shown on the attached Record of Borehole sheets. The following paragraphs provide simplified descriptions of the subsurface conditions in terms of major soil strata for the purposes of geotechnical design. The soil boundaries have been inferred from noncontinuous samples and observations of sampling and drilling resistance. The soil boundaries shown represent transitions from one soil type to another and should not necessarily be interpreted to represent exact planes of geological change. Further, the subsurface conditions will vary between and beyond the borehole locations. 5.1 Soil Conditions The soil conditions encountered in the boreholes generally consisted of the existing pavement structure or surficial topsoil overlying granular fill materials, buried topsoil, clayey silt, silt, sand, silty sand, gravelly sand and glacial till. Asphaltic concrete (asphalt) was encountered at the pavement surface in BH-102, drilled immediately east of the sidewalk east of Adelaide Street. The thickness of the asphalt was 60 millimetres. Gravelly sand, interpreted to be granular base based on visual examination, was encountered in BH-102 beneath the asphalt and was about 400 millimetres thick. Topsoil was encountered at the ground surface in BH-101. The surficial topsoil was about 180 millimetres thick. Buried topsoil was encountered beneath fill materials in BH-101 and beneath the pavement structure in BH-102. The buried topsoil was about 0.5 and 0.9 metres thick at the borehole locations. Samples of the buried topsoil had water contents of about 19 and 26 per cent. Materials designated as topsoil in this report were classified solely based on visual and textural evidence. Testing of organic content or for other nutrients was not carried out. Therefore, the use of materials classified as topsoil cannot be relied upon for support and growth of landscaping vegetation. Report No R01 2

6 ADELAIDE STREET AT CPR UNDERPA Granular fill materials, consisting of sandy silt and sand, were encountered beneath the surficial topsoil in BH-101 and beneath the buried topsoil in BH-101 and BH-102. The granular fill was about 0.3 to 1.8 metres thick. The fill had standard penetration test (SPT) N 1 values of 3 and 8 blows per 0.3 metres with water contents ranging from about 11 to 20 per cent. The fill materials also contained varying amounts of topsoil. Layers of cohesive soils were encountered beneath the granular fill in BH-101 and BH-102 which consisted of clayey silt about 0.8 and 1.5 metres in thickness. The clayey silt had SPT N values ranging from 8 to 19 blows per 0.3 metres with water contents ranging from about 9 to 11 per cent. Granular deposits, consisting of sand, silty sand and silt, were encountered below the clayey silt in BH-101 and BH-102. The granular deposits were about 3.1 and 4.6 metres thick at the borehole locations. The granular soils had SPT N values ranging from 19 to greater than 100 blows per 0.3 metres with water contents ranging from about 9 to 26 per cent. The results of grain size analyses carried out on standard penetration test samples of the silty sand are shown on Figure 2. A grain size distribution curve for a sample of the silt is provided on Figure 3. Sandy silt to clayey silt glacial till was encountered beneath the granular deposits in both boreholes. The boreholes were terminated in the glacial till after exploring the layers for about 5.4 and 5.9 metres. The glacial till in BH-101 contained layers of very dense gravelly sand. The glacial till and associated gravelly sand layers had SPT N values ranging from 54 to greater than 100 blows per 0.3 metres, inferred from the effective refusal to split spoon sampler penetration within the deposit. Water contents within the glacial till ranged from about 8 to 19 per cent. Although not encountered in the boreholes, the glacial till and gravelly sand should be expected to contain cobbles and boulders. 5.2 Groundwater Groundwater conditions were observed in the boreholes during drilling and a piezometer was installed in borehole BH-101 as shown on the Record of Borehole sheets. The results of the observations and measured groundwater levels are shown on the Record of Borehole sheets. The encountered groundwater level in BH-101 and BH-102 ranged from depths of 2.9 to 7.5 metres below ground surface or between elevations and metres. Groundwater levels measured in the piezometer installed in BH-101 on November 15 and 30, 2016, were at depths of about 4.4 and 5.0 metres below ground surface or approximately elevations and metres, respectively. It should be noted that groundwater levels encountered during drilling are not necessarily indicative of long-term conditions and groundwater levels will vary significantly in response to significant precipitation events. 1 The SPT N value is defined as the number of blows required by a 63.5 kilogram hammer dropped from a height of 760 millimetres to drive a split spoon sampler a distance of 300 millimetres into the soil after having first penetrated 150 millimetres. Report No R01 3

7 ADELAIDE STREET AT CPR UNDERPA 6.0 DISCUION AND RECOMMENDATIONS Based on the information provided to Golder, Adelaide Street will be lowered as much as 7 metres and a new single or two span rail bridge will be constructed to carry rail traffic over Adelaide Street. A preliminary design profile was provided by the City for reference during preparation of this report. All recommendations provided below are preliminary and should be reviewed and revised upon receiving updated design information. This section of the report provides our interpretation of the factual geotechnical data obtained during the field work and laboratory testing and it is intended for the guidance of the design engineer. Where comments are made on construction, they are provided only to highlight those aspects which could affect the design of the project. Contractors bidding on or undertaking the work should make their own interpretation of the subsurface information provided as it affects their proposed construction methods, equipment selection, scheduling and the like. Based on the profile provided by the City to Golder, the Adelaide Street grade lowering will be as much as 7 metres in depth. Based on our interpretation of the factual data obtained from the boreholes advanced in the vicinity of the proposed underpass during the subsurface investigation at this site, the subsurface soil conditions consist of about 2.1 metres of very loose to loose topsoil and fill materials underlain by stiff to very stiff clayey silt which overlie compact to very dense granular deposits and very dense or hard glacial till with interbedded gravelly sand layers. The groundwater elevation at the at the site is about 4.5 metres below the ground surface or at approximately elevation metres, some 2.5 metres above the planned road surface elevation. It is estimated that as much as 200 metres of the new Adelaide Street pavements will be below the groundwater level. As the new bridge structure to carry rail traffic at grade over Adelaide Street will support a railway line, the geotechnical recommendations in the following sections are in accordance with the American Railway Engineering and Maintenance-of-Way Association (AREMA) Manual for Railway Engineering, where applicable. The most significant issue for this project will be short and long-term management of groundwater levels. Based on the borehole and observation well (piezometer) data, the future road surface will be on the order of 2.5 metres below groundwater levels at its deepest point. The ground conditions above the future road level consist of layered silt, sand and gravel soils that will likely produce significant flows of water that, unless the work is designed to be effectively water tight, will need significant, multilevel dewatering systems for construction as well as either a permanent groundwater cut-off system (e.g., secant pile wall) with a supplementary internal drainage and pumping system, or a long-term groundwater drawdown pumping system. 6.1 Excavations and Groundwater Control Based on the results of the field work, excavations at this site will be difficult, generally due to the presence of groundwater about 2.5 metres above the planned pavement surface and the requirement to depressurize the glacial tills and silts. Excavations for the project are expected to encounter the existing pavement structure, topsoil, fill materials (both those identified in the boreholes and those associated with the backfill for the existing services), cohesive soils, granular deposits and glacial till, depending on excavation depth. The groundwater elevation at the site is estimated to be at approximately metres. However, groundwater levels should be expected to fluctuate seasonally and in response to significant precipitation events which could result in groundwater levels being higher than those encountered during this investigation. Report No R01 4

8 ADELAIDE STREET AT CPR UNDERPA Proactive dewatering and depressurization will be required, likely using vacuum well points and eductors or deep wells at properly spaced intervals together with strategically placed bleeder wells. The well point and eductors or deep well systems will likely be required to control the groundwater flows from the granular soils into the open excavations. In addition, depending on the final depths of excavations required, the deep wells will likely be required to control the water at the granular/glacial till interface and reduce the potential for loss of ground due to flowing of these materials. Granular layers beneath the clayey silt till and sandy silt till, particularly those encountered in BH-101, are likely pressurized and, depending on excavation depths and success of the dewatering, may require depressurization using bleeder wells to prevent base heave, or hydraulic uplift, due to the water pressures. A two-tiered (at grade well points and additional well points installed in a pre-cut) system will be necessary based on the anticipated depths of excavations. Groundwater pressure relief holes (bleeder wells), for preliminary consideration, would be drilled on regular intervals of about 5 metres centre-to-centre prior to commencement of the excavations and extend to about elevation 238 metres. Following drilling, the holes would be backfilled with concrete sand to allow controlled upward flow of water and relief of groundwater pressures. A Permit to Take Water (PTTW) from the Ministry of Environment and Climate Change will be required. A detailed hydrogeological assessment will also be required. Some relief of these dewatering requirements could be made should the project area below the anticipated water level be enclosed within a diaphragm system socketed into the glacial till. Provided the system is sufficiently water tight, a sump and pump operation could be utilized to remove the water to complete construction in the dry. However, depending on the actual depths of excavation required, bleeder wells may still be required to address upward water pressures. It is anticipated that a diaphragm system will be the most practical and feasible alternative. All excavations should be carried out in accordance with the current Occupational Health and Safety Act and Regulations for Construction Projects (Act) criteria. All open cut slopes should be maintained at inclinations of 1 horizontal to 1 vertical or flatter and may need to be flatter in the existing fill materials. Based on the Act, the existing fill materials would be considered Type 3 soils where these are above the water level. The cohesive soils are expected to behave as Type 2 soils as would the native granular soils above the water level. Fill, if present, and the native granular soils below the groundwater level would be classified as Type 3 or Type 4 soils and the glacial tills would be classified as Type 1 soils. If properly dewatered, the native granular soils could be considered Type 2 or Type 3 soils, depending on the method and effectiveness of the dewatering. Care should be taken to direct all surface water away from open excavations. Long term groundwater management systems will likely be required. Long term pumping systems will need to be installed for the underpass to avoid hydraulic uplift pressures of the underlying granular soils on the roadway pavements. Also, permanent, full perimeter cut-off wall systems may be needed to limit long term pumping flows within the perimeter retaining wall systems. Report No R01 5

9 ADELAIDE STREET AT CPR UNDERPA 6.2 Rail Bridge Foundations Shallow Foundations The new bridge structure may be founded on conventional spread/strip foundations, depending on settlement tolerances and constructability considerations. Provided appropriate groundwater control is implemented during and following construction and protection against freezing is provided, spread foundations for the bridge abutments and, if required, piers may be founded at or below elevation 240 metres or about 9 metres below the existing ground surface in the very dense granular deposits or very dense to hard glacial tills. A factored geotechnical resistance at ULS of 750 kilopascals (kpa) and a geotechnical reaction at SLS of 500 kpa may be used for preliminary design of shallow foundations at or below the elevations noted above. Typically, SLS values correspond to an estimated total settlement of 25 millimetres. For the purposes of this report, a footing width on the order of 3.5 metres and footing length of about 13.5 metres have been assumed. Prior to final design, however, detailed settlement estimates should be completed once detailed foundation load information is available. All footings should be provided with a minimum of 1.2 metres of earth cover or thermal equivalent for frost protection purposes (in accordance with Section of the AREMA Manual for Railway Engineering). Construction of spread foundations for the abutments and piers will require extensive dewatering/unwatering since the excavations will extend approximately 4 to 5 metres below the anticipated water levels. Excavation support systems would also be required to support the relocated rail lines and adjacent infrastructure. The geotechnical resistance ( bearing capacity ) values provided above are recommended under the assumption that the loads will be applied perpendicular to the surface of the footings. Where the load is not applied perpendicular to the surface of the footing, inclination and eccentricity of the load should be taken into account (in accordance with Section 3.5 of the AREMA Manual for Railway Engineering). The bearing stratum for the footings founded at the above elevation is expected to be very dense granular deposits or hard glacial till. As such, the resistance against sliding between a cast-in-place concrete footing and the bearing stratum should be based on an unconfined compressive strength of 150 kpa (in accordance with Section of the AREMA Manual for Railway Engineering). The above resistance should not be greater than the sliding resistance derived using a coefficient of friction of Deep Foundations If, once detailed foundation load information is available, spread foundations are not suitable, deep foundations may be used for support of the abutments or piers, although pile or drilled shaft foundations may be relatively short. Due to the very dense to hard founding soils at the site, steel H-piles or steel tube piles would likely encounter refusal at nominal depths below the future road elevation of metres, depending on the elevations at which pile driving commenced, and would not be practical for this project. Drilled shaft foundations (caissons) could also be used for the foundations of the abutments or piers and would be the preferable geotechnical option if deep foundations were required. Alternatively, H piles could be installed in pre-drilled, lined holes and concreted in place though, for the purposes of this report, drilled shafts and H piles installed in pre-drilled holes filled with structural concrete are considered equivalent. Drilled shafts (drilled piles or caissons) with tip elevations at about elevation metres or below may be designed using the geotechnical resistances noted in the following table. The SLS values correspond to a maximum of 25 millimetres of total settlement for new construction. Higher capacity foundations could be achieved, Report No R01 6

10 ADELAIDE STREET AT CPR UNDERPA if necessary, by extending the drilled diameter, depth or both. Appropriate drilling diameters and depths should be evaluated for high capacity foundations once structural loads are defined. Pile Type Assumed Tip Elevation (m) Approximate Cut-off (Top) Elevation (m) Approximate Pile Length (m) Factored Geotechnical Resistance at ULS (kn) Geotechnical Reaction at SLS (kn) 0.6 m diameter Drilled Shafts 0.9 m diameter Drilled Shafts , The maximum ultimate resistance of two times the factored ULS value shown in the above table should be noted on the foundation drawing. The drilled shaft operations should be carefully monitored by this office to confirm that the design capacities are being achieved. The drilled shafts will require lining of the holes during construction and use of drilling fluids to maintain the integrity of the soils surrounding the drilled hole and at the drilled hole base. Drilling slurry might not be required during concrete placement if the drilled shafts extend below elevation 236 metres where the tips are fully within the glacial till. However, during drilling, water or slurry will likely be required to avoid ground losses while drilling through the saturated granular deposits. Concreting of the drilled shafts using tremie techniques may also be required. All pile caps should be provided with a minimum of 1.2 metres of soil cover for frost protection (in accordance with Section of the AREMA Manual for Railway Engineering). For preliminary design purposes, the ultimate lateral resistance of individual piles can be based on the passive soil resistance applied over a horizontal distance (vertical plane) equal to the minimum of either three times the pile diameter or the spacing between piles. Horizontal resistances and corresponding displacements for the piles shafts can be estimated using the following equation and ranges in subgrade reaction coefficient where: k h = where: d coefficient of horizontal subgrade reaction (MPa/m) nh Su z = nh (z/d) for cohesionless soils = 67 Su_ for cohesive soils d = Pile or shaft width or diameter (m) = constant of horizontal subgrade reaction (MPa/m) = undrained shear strength of the soil (MPa) = depth below ground surface grade (m) Report No R01 7

11 ADELAIDE STREET AT CPR UNDERPA The stratigraphy presented in the table below has been simplified for the purposes of this report. The range in values reflects the variability in subsurface conditions as well as the two extremes of design: the requirement for flexibility if integral abutments are selected, and the requirement for lateral support in the cases of non-integral abutment foundations. In this case, the lateral load resistance in any fill and organic soils should be neglected. Location Soil Type Elevation (m) nh (MPa/m) Su (MPa) Native soils Stiff to very stiff cohesive soils Compact to very dense native granular soils Hard or very dense glacial till or very dense granular soils From to From to to Below to 0.3 If the design is found to be sensitive to the horizontal modulus of subgrade reaction, additional analyses should be carried out to refine these parameters given specific foundation sizes, displacement tolerance(s), and static and dynamic load characteristics along with sufficient information to ascertain whether the shafts are most representative of fixed or free end conditions at the pile cap elevation. Group action for lateral loading should be considered when the pile or shaft spacing in the direction of the loading is less than six to eight pile diameters. Group action can be evaluated by reducing the coefficient of horizontal subgrade reaction in the direction of loading by a reduction factor R as follows: Pile or Shaft Spacing in Direction of Loading, d = Pile Diameter Subgrade Reaction Reduction Factor R 8d d d d CP Rail Detour A temporary rail detour will be required to direct the rail traffic during construction of the new rail bridge structure. Based on the soil conditions encountered in the boreholes, the subsurface conditions in the area of a proposed detour (either north or south of the existing tracks, depending on rail alignment constraints) consist of about 2.1 metres of fill material or buried topsoil underlain by layers of clayey silt, silts, sands and glacial tills. As the railway detour has not been finalized, the following section of this report provides general geotechnical comments related to the design and construction of the temporary track detour. Report No R01 8

12 ADELAIDE STREET AT CPR UNDERPA The buried topsoil and very loose to loose fill materials are not considered suitable for support of the temporary rail detour and should be removed. Engineered fill may be constructed at the rail detour to bring the area to grade. Following removal of all topsoil and fill material, the prepared subgrade should be heavily proofrolled under the supervision of a geotechnical engineer. Any poorly performing areas of the subgrade should be sub-excavated and replaced with engineered fill. The engineered fill should consist of select granular earth fill approved by the geotechnical engineer or imported City of London Select Granular B. The approved engineered fill materials should be placed in maximum 300 millimetre thick loose lifts and compacted to at least 98 per cent standard Proctor maximum dry density (SPMDD). Filling should continue until the design subgrade elevations are achieved. Care will be required to ensure that the prepared area extends far enough to encompass the limits of the engineered fill. The lateral limit of the engineered fill is defined as the depth of the fill to be placed plus one metre and is to be applied beyond the outside edge of the ballast. Golder can provide input regarding required ballast and subballast thicknesses, if required; however, information will be required from CN regarding train frequency, loads and any specific design criteria. 6.4 Seismic Analysis Based on the results of the boreholes, a Site Class C designation could be used for design in accordance with Section 4 of the Canadian Highway Bridge Design Code (CHBDC). According to Table A of the CHBDC, the zonal acceleration ratio, A, applicable to London, Ontario is The corresponding acceleration related seismic zone, Za is 0. The following seismic performance zones (SPZ) are applicable to the proposed structure based on the assigned importance category: Importance Category Seismic Performance Zone Lifeline bridge 2 Emergency route and other bridges 1 It is understood that this structure is not considered to be a lifeline bridge and is classified as Seismic Performance Zone 1. Multi-span bridges of construction other than a truss, as we assume the subject structure is not, need not be analyzed for seismic loads if they are classified as Seismic Performance Zone 1. However, design forces for restraining elements and bridge support lengths must meet the minimum requirements as outlined in CHDBC Clause The effects of site conditions on the bridge response are to be included in the determination of the seismic loads. The stratigraphy generally consists of the existing pavement structure or topsoil overlying very loose fill materials, stiff to very stiff cohesive deposits and compact cohesionless soils. The density/consistency of the deposits are very dense/hard below approximately elevation metres. None of the boreholes advanced at this site encountered bedrock. The available mapping indicates that limestone of the Dundee Formation is present at approximately elevation metres. Based on the site stratigraphy, the soil profile type is categorized as Type I with a seismic site response coefficient, S, of 1.0 based on the CHBDC criteria. Report No R01 9

13 ADELAIDE STREET AT CPR UNDERPA Seismic Hazard Assessment The site location has historically been considered to be in an area of low seismicity with a peak ground acceleration (PGA) of 0.04g from an earthquake with a 10 per cent probability of exceedance in 50 years. A preliminary screening of the soil stratigraphy was conducted using the procedure outlined in the Federal Highway Administration recommended procedures 2. The granular layers generally have a normalized N value of greater than 30 blows per 0.3 metres and often greater than 50 blows per 0.3 metres. These deposits also date to the Pleistocene era. Deposits from the Pleistocene era historically have a very low to low susceptibility to liquefaction upon strong ground shaking. Therefore, the liquefaction potential is considered to be low based on the soil profile type, age of the deposits, relative density and the historically low seismicity. Therefore, a detailed evaluation of the liquefaction potential of the foundation soils, impact of liquefaction on the bridge foundations and the effect of seismic forces on embankment stability is not considered warranted. 6.5 Retaining Walls The following sections of this report discuss the temporary and/or permanent retaining/shoring structures that may be feasible and practical for the site, as follows: Secant pile (caisson) walls; Soldier pile and lagging walls for permanent construction above groundwater or for temporary support when dewatering is provided; and Conventional cast-in-place concrete or retained soil system (R)/mechanically stabilized earth (MSE) walls for permanent construction above groundwater levels. Sheet pile or driven pipe pile systems are not considered feasible due to the very dense granular soils and very dense/hard glacial tills Lateral Earth and Water Pressures The shape of the soil pressure distribution diagram behind a retaining system depends upon the type of soil to be retained, the flexibility of the wall and the amount of movement that can be permitted. Typically, permanent retaining systems are designed to be relatively rigid and shoring systems are design to be stiff and restrained against movement or flexible depending on the need to protect nearby infrastructure. The sequence of work may also alter the shape of the pressure diagram during the various construction phases. Earth pressure computations must also take into account the groundwater level. Above the groundwater level, earth pressure is computed using the bulk unit weight of the retained soil. Below the groundwater level, the earth pressures are computed using the submerged unit weight of the soil. A hydrostatic pressure is also applied if the retained soil is not fully drained. Calculation of earth pressures acting on retaining structures due to strip loads, 2 Federal Highway Administration (FHWAp). (1997). Design Guidance: Geotechnical Earthquake Engineering For Highways. Volume I Design Principles. Geotechnical Engineering Circular No. 3:FHWA-SA , Washington, D.C. Report No R01 10

14 ADELAIDE STREET AT CPR UNDERPA line loads and point loads should be computed in accordance with Section 20.3 of the AREMA Manual for Railway Engineering. The lateral earth pressure coefficients chosen for design require certain movements for the active and passive conditions to be mobilized and the stiffness of the wall may not allow such displacements. Tolerable displacements for the design of the walls may also be less than the required displacements to mobilize the active and/or passive earth pressures. The displacements required to mobilize the active and passive conditions can be estimated from Figure C6.16 in the Commentary to the CHBDC. The recommended unfactored values of the parameters for use in the preliminary design of retaining structures that permit small lateral movements are provided in the following table. Earth Pressure Coefficients Soil Effective Angle of Internal Soil Friction, (degrees) Active Earth Pressure Coefficient, Ka At-Rest Earth Pressure Coefficient, Ko Passive Earth Pressure Coefficient, Kp Stiff to very stiff clayey silt Compact silts and sands Dense to very dense granular soils Very dense to hard glacial till Secant Pile (Caisson) Walls A secant pile wall (or caisson wall ) is constructed by drilling holes, typically between 0.9 and 1.2 metres in diameter, inserting steel reinforcement in the form of steel beams or reinforcing bars, and filling the holes with concrete. The secant pile wall is formed by having each pile overlap the adjacent pile. A permanent secant pile wall often has a permanent cast-in-place or precast concrete facing attached to the front surface to fill any gaps between piles and provide a smooth or architecturally appropriate surface finish. A secant pile wall can be designed as a cantilever wall up to a site-specific limiting height on the order of 5 to 7 metres or, with permanent tie-backs or other bracing systems, large heights can be achieved. In some cases, where tie-backs or bracing are not feasible, piles as large as 2 metres in diameter can be constructed to allow higher unbraced/unrestrained cantilever walls. Permanent secant pile walls must also include provisions for frost protection and control of groundwater seepage. The main advantages of a secant pile wall are increased wall stiffness compared to the more flexible sheet pile, soldier pile and lagging or soil nail wall systems, control of ground and groundwater by pile interlock, and the ability to be used in difficult ground containing cobbles or boulders. At this site, the primary advantage of this wall system is its ability to serve as both a permanent groundwater cut-off system as well as a retaining structure. The main disadvantages are that they are relatively expensive to construct and full waterproofing may be difficult to achieve at the joints. For a preliminary secant pile wall design, the lateral earth pressures may be calculated as provided in Section 6.5.1, above, and lateral resistances using the methods summarized for deep foundations in Section of this report. Report No R01 11

15 ADELAIDE STREET AT CPR UNDERPA For the conceptual/preliminary assessment of retaining structure performance at the Adelaide Street site, it is anticipated that secant pile (caisson) walls will undergo maximum horizontal and vertical displacements of about 0.1 to 0.2 per cent of the total excavation depth with the higher value associated with cantilever walls. For maximum wall heights of approximately 7 metres, this translates to displacements on the order of about 7 to 14 millimetres of deformation at this site, provided that appropriate construction procedures and workmanship are adopted Soldier-Pile and Lagging Walls Soldier pile and lagging systems are commonly used for earth retention and can be constructed in a variety of ground conditions provided that groundwater is either absent or appropriately controlled. After installation of the soldier piles, the excavation proceeds and lagging (timber boards, concrete or steel sheeting) is inserted behind the front flanges or placed against the piles and attached to the front flange using fasteners. The lagging is often installed in lifts of 1 to 1.5 metres, depending on the ground conditions. For permanent installations, pre-cast concrete lagging is normally used but the alignment must be closely controlled during installation of the soldier piles to ensure a proper fit. Permanent soldier pile and lagging walls must also include provisions for frost protection and control of any groundwater seepage. To resist lateral forces and to control lateral wall movement, soldier pile and lagging walls with total retained heights much over 5 metres typically require horizontal restraints. Where the excavation is wide and must be free from obstructions, tie-backs are typically used rather than rakers or cross-bracing. The use of tie-backs is contingent upon the absence of underground utilities and the presence of suitable soils or rock in which to install anchors in the tieback area. At this site, the use of soldier pile and lagging walls will likely be restricted to temporary support of excavations and the existing railway where full dewatering is carried out, for excavations above groundwater levels and possibly for cantilever permanent retaining walls above the groundwater levels. For a preliminary design of cantilever soldier pile and lagging walls, the lateral earth pressures may be calculated as provided in Section 6.5.1, above, and lateral resistances using the methods summarized for deep foundations in Section of this report. For the conceptual/preliminary assessment of retaining structure performance at the site, it is anticipated that cantilever soldier pile and lagging walls designed to resist the lateral earth pressures as defined above will undergo a maximum horizontal and vertical displacement of about 0.2 to 0.3 per cent of the total excavation depth. If such displacements are not acceptable, stiffer wall systems can be designed to further control movements. This estimated displacement assumes high quality workmanship; however, it is noted that ground loss can be more common with this type of retaining system, especially during lift excavation and installation of lagging elements, and there is some risk for higher displacements to occur in the event of ground loss or otherwise poor workmanship Cast-in Place Concrete and R/MSE Retaining Walls Gravity retaining walls, such as conventional cast-in-place concrete walls or retained soil system (R) walls (also referred to as mechanically stabilized earth or MSE walls) may be appropriate for some sections of this project. Where the cut made for the underpass extends below the groundwater level, these wall systems will likely not be Report No R01 12

16 ADELAIDE STREET AT CPR UNDERPA appropriate unless long-term groundwater lowering/drainage systems are incorporated into the design. However, in areas where the cuts will not extend below groundwater levels, conventional cast in place concrete and R walls may be both suitable and cost effective for this project. Cast-in-place concrete or R walls may be founded at about elevation 245 metres or approximately 3.9 metres below the ground surface in the very stiff clayey silt or compact silt. A factored geotechnical resistance at ULS of 300 kilopascals (kpa) and a geotechnical reaction at SLS of 200 kpa may be used for conceptual design of shallow foundations at the elevation noted above. If founding in the granular deposits at or below elevation 245 metres, a factored geotechnical resistance at ULS of 450 kpa and a geotechnical reaction at SLS of 300 kpa may be used for conceptual design of shallow foundations. The SLS values correspond to an estimated total settlement of 25 millimetres. It is anticipated that these geotechnical reaction values will not govern design of R walls and, depending on the anticipated configuration of the wall systems and the associated bearing pads for facing systems, higher geotechnical resistance values may be appropriate. If cast-in-place concrete retaining walls are to be used, the geotechnical resistance values will need to be updated and will depend on the overall foundation dimensions. Lateral pressures acting on the above-noted gravity retaining walls will depend on the type and method of placement of the backfill materials, on the nature of the soils behind the backfill, on the freedom of lateral movement of the structure, the drainage conditions behind the walls and the type of reinforcement (geotextile, geogrids or metallic strips). For preliminary design of cast-in-place concrete or R walls, active, at-rest and passive lateral earth pressures associated with the native ground and surcharge pressure may be calculated as provided in Section In general, if the wall allows lateral yielding, active earth pressures may be used in the geotechnical design of the structure. If the wall does not allow lateral yielding, at-rest earth pressures should be assumed for geotechnical design. Pressure arising from compaction equipment and construction procedures must be taken into account. A compaction surcharge equal to 12 kpa should be included in the lateral earth pressures for the structural design of the retaining walls, in accordance with CHBDC, Figure 6.6. Typically, R wall suppliers and fabricators will complete the engineering related to lateral earth pressure on these walls once the backfill materials have been selected. Select, free-draining granular fill meeting the grading requirements for OP Granular A or Granular B but with less than 5 per cent passing the 75 micron sieve should be used as backfill behind the wall. Granular backfill may be placed either in a zone with a width equal to at least 1.2 metres behind the back of the cast-in-place concrete retaining structures or the reinforced mass of an R system (Case (a) from Commentary on CHBDC Figure C6.20) or within the wedge-shaped zone defined by a line drawn at a maximum 1 horizontal to 1 vertical slope extending up and back from the rear face of the wall or R mass (Case (b) from Commentary on CHBDC Figure C6.20). For Case (a), the restrained case, the preliminary design pressures are based on an assumption that a material similar to Select Subgrade Materials (M) will be used since these are typically the least cost fill soils and for this assumption the following parameters (unfactored) may be used: Soil unit weight: 20 kn/m³ Coefficients of lateral earth pressure: Active, Ka 0.33 At rest, Ko 0.5 Passive, Kp 3.0 Report No R01 13

17 ADELAIDE STREET AT CPR UNDERPA For Case (b), the pressures are based on granular fill being used and the following parameters (unfactored) may be assumed: GRANULAR A CITY OF LONDON GRANULAR B Soil unit weight: 22 kn/m³ 22 kn/m³ Coefficients of lateral earth pressure: Active, Ka At rest, Ko Passive, Kp It should be noted that the above design parameters assume level backfill and ground surface behind the wall. The lateral earth pressure coefficients should be adjusted if there is sloping ground behind the wall. The resistance to lateral forces/sliding resistance between the retaining wall footing and the subgrade should be calculated in accordance with Section of the AREMA Manual for Railway Engineering or the CHBDC, as appropriate, and may be estimated using the following equation: Hri = 0.8A'c' + 0.8Vtan > Hf Where: A' = effective contact area, square metres c' = Nil tan = given in the table below V = unfactored vertical force, kilonewtons Hf = factored horizontal load, kilonewtons Each retaining wall should be checked for overturning. Assuming that the founding soils are not loosened/disturbed during excavation and footing construction, angles of interface friction and corresponding unfactored coefficient of friction, tan δ, as provided in the table below, may be used for the interaction between the base of the wall and the founding soil. Wall Type Reinforced Concrete Gravity or Cantilever Wall and R Block System Wall on concrete footings R Block System Interaction Angle of Friction, δ (degrees) Coefficient of Friction, Tan δ Cast-in-place concrete footing on clayey silt or silt Cast-in-place concrete footing on sand Pre-cast concrete block facing units on Granular A levelling pad Report No R01 14

18 ADELAIDE STREET AT CPR UNDERPA Global Stability of Retaining Walls The global stability of retaining structures will be dependent on the type of wall, its geometry and location relative to adjacent structures, and the engineering characteristics of the fill and native soils. Without details regarding planned cut depths and retaining wall geometry, it is not possible to appropriately assess specific global stability factors of safety for retaining structures at this site. However, given the native soil conditions, provided that groundwater is appropriately controlled for both temporary and permanent conditions, global stability factors of safety for retaining walls constructed at this site are expected to be satisfactory Tie-Backs/Ground Anchors Tie-backs, also called ground anchors, are constructed by drilling horizontal or sub-horizontal holes into the ground behind the wall as the excavation proceeds downward. After the hole is drilled, steel rods or high-strength steel strands are inserted into the hole and an anchor zone is then created by filling the annular space around the steel rods or strands with cement grout. Often, the cement grout is injected under pressure. The anchor zone is typically located beyond the active earth zone behind the wall (the mass of earth that deforms and places load on the wall). After the grout is cured, the anchor is pre-stressed to its design load, structurally connected to the wall and the remaining annular space between the anchor zone and the wall face, called the free length, is backfilled. Tie-backs offer an unrestricted excavation once they are in place but permanent tie-backs can limit future subsurface use since the integrity of the tied-back walls depends on the ground around the tie-backs remaining undisturbed. Permanent tie-backs also require additional corrosion protection detailing, particularly for walls that are exposed to roadway deicing salts. For planning purposes, it may be assumed that the anchors extend back from the face of the wall a distance equal to 1.5 times the excavation depth. The horizontal and vertical spacing of the tie-backs will largely depend on the stiffness of the vertical wall elements, the loads that are distributed to the tie-backs, the capacity of the ground in which they are anchored to resist the load, tolerable displacements of the ground and facilities around the excavation, and the cost for installing the tiebacks. Typically, the spacing of tie-backs (both vertically and horizontally) is limited to about 5 metres. Larger spans can be achieved but the required bending moment capacity of the vertical wall elements must be substantially greater than typical excavation support installations. It may also be necessary to install wales (long structural sections that support the wall horizontally) between supports. Wales can consist of steel sections or, in the case of permanent installations, cast-in-place concrete. For this site, permanent tie-back installations can be made in the native compact to very dense granular materials or very dense to hard glacial tills. Depending on the angle at which tie-backs are installed, the vertical component of the tie-back load can be significant and the design of earth retaining systems must take this vertical load into account. Vertical wall members must be capable of supporting the vertical load component while maintaining vertical settlement within tolerable limits. Excessive vertical wall movement can cause loss of tension in the tiebacks and poor performance of the entire excavation support system. If required, improved anchor bond strengths can be achieved within the native materials by post-grouting. Apart from increasing the apparent bond stress, the technique also has the advantage of allowing individual anchors to be re-grouted and improved if proof-testing shows a particular anchor to be deficient. Since the anchor bond zones are expected to be formed within the native glacial till and granular deposits, and based on the anticipated geometry, it is expected that secondary pressure grouting will not have a negative impact (i.e., heave) on the existing structure footings adjacent to the proposed retaining walls. Report No R01 15

19 ADELAIDE STREET AT CPR UNDERPA For the preliminary design, the capacities of the anchors may be calculated using the method provided in the Canadian Foundation Engineering Manual (CFEM, 2006) as follows: For cohesive deposits: where Par = Φ su As Ls αc Par = pull-out resistance of the grouted ground anchor (kn) Φ = resistance factor = 0.4 or 0.6 (ULS as noted below) su = average undrained shear strength of the soil (kpa) As = effective unit surface area of the anchor bond zone (i.e., circumference) (m 2 /m) Ls = effective length of the anchor bond zone (limited to approximately 8 m) αc = adhesion (reduction) factor related to the undrained shear strength For granular deposits: where Par = Φ σ z As Ls αg Par = pull-out resistance of the grouted ground anchor (kn) Φ = resistance factor = 0.4 or 0.6 (ULS, as noted below) σ z = effective vertical stress at the midpoint of the load carrying length (kpa) As = effective unit surface area of the anchor bond zone (i.e., circumference) (m 2 /m) Ls = effective length of the anchor bond zone (limited to 8 m) αg = adhesion/bonding factor The anchors may be sized based on the following ultimate adhesion capacities acting between the grout and soil. Soil Type Single-Stage Pressure Grouted Anchors Secondary Pressure Grouted Anchors Stiff to very stiff clayey silt 60 kpa 90 kpa Compact sands and silts 100 kpa 165 kpa Dense to very dense silty sand, sand and gravelly sand 150 kpa 250 kpa Very dense to hard glacial tills 150 kpa 250 kpa Since the ground-to-anchor bond stress is highly dependent on the construction/installation techniques, the shoring system installation contractor must be held to an anchor performance specification. The specification should include proof testing, lift off tests and performance testing on all or a proportion of the anchors, as required (e.g., performance tests on at least 10 per cent of the anchors, proof testing should be performed on the remaining 90 per cent and lift-off tests to be performed on all anchors). Report No R01 16

20 ADELAIDE STREET AT CPR UNDERPA For design of the permanent anchors under tension based on static analysis and in the absence of pull out testing, a resistance factor of 0.4 should be used. A resistance factor of 0.6 may be used if pull out tests are carried out. The sustained working load should not be greater than 60 per cent of the ultimate tensile strength of the anchor tendons or bars. The fixed length (bond zone) of the anchors should be maintained in the stiff to very stiff cohesive soils or dense to very dense non-cohesive soils behind a line drawn upward at 45 degrees from the base of the shoring walls. A fixed anchor length of at least 5 metres but not greater than 10 metres is recommended for soil anchors. It is anticipated that soil anchors would be installed consistent with the locations of soldier piles or reinforced caissons (and thus on the order of 2 to 3 metres apart). All installed anchors should be proof-loaded to 1.25 times the design load and locked off at 1.1 times the design load. Anchor testing should be supervised by experienced geotechnical personnel Monitoring of Track Protection Retaining Walls Monitoring of track protection retaining wall systems is typically carried out during and following installation to observe and, if necessary, correct the performance of such systems to maintain track safety and displacements within tolerable limits. Commonly, surveying targets installed at the top of the shoring system and in the ground between the tracks and shoring system have been used for this purpose. For relatively high retaining walls (greater than about 5 metres) in close proximity to the tracks, inclinometers installed immediately behind the face of the retaining systems are essential for monitoring the response of the wall and ground to progressive excavation activities. Measurement of the vertical and horizontal displacement of the retaining system and ground should be taken twice daily during installation of the protection system and excavation for construction of the new pile caps. Measurements should be taken twice weekly upon completion of the pile cap or foundation construction, backfilling and decommissioning of the track protection system. The monitoring results should be promptly reported to the designer, Contract Administrator and railway owners (or representatives) following each monitoring event. 6.6 Backfill Backfill adjacent to foundations should consist of free draining Granular B material. The Granular B backfill should be placed in loose lift thicknesses not exceeding 200 millimetres and be uniformly compacted to at least 98 per cent of SPMDD. Effective drainage of the backfill should be provided using properly filtered weep holes and drains. Report No R01 17

21 ADELAIDE STREET AT CPR UNDERPA 6.7 Pavements Based on the results of the investigation, the existing approach pavement structure will be constructed on native materials consisting of compact to very dense granulars. The following pavement component thicknesses placed on a competent, properly prepared subgrade are recommended: Component Thickness (mm) Asphalt 150 (50 HL 3 surface, ) HL 8 binder) Granular A Base 150 City of London Granular B Subbase 300 The subgrade should be proofrolled under the direction of the geotechnical engineer and any excessively soft/poorly performing areas addressed accordingly. Any fill, organics or deleterious materials encountered at subgrade level should be removed prior to placement of the pavement granulars. If the underlying soils consist of dense to very dense native granulars, the Granular B subbase is not required provided that the Granular A base is thickened to 200 millimetres. The Granular A base and Granular B subbase material should be uniformly compacted to at least 100 per cent of the SPMDD, respectively. The asphaltic materials should be produced, placed and compacted in accordance with Ontario Provincial Standard Specifications (OP) requirements for medium duty pavements. 6.8 Permanent Drainage System Permanent drainage of the roadway and pavements will be required to reduce the potential for hydraulic uplift. During subgrade preparation, a subdrain system could be installed beneath the pavement granular materials at an appropriate depth and spacing and of proper size to collect groundwater and direct it to a dedicated outlet. This system should be carefully connected to the bleeder well system to maintain its long-term effectiveness. Depending on the retaining structure type selected to construct the underpass, effective drainage behind the walls may also be required. It is expected that either a deep gravity sewer or a pumping station will be required to manage groundwater flows. Further, it is highly recommended that a redundant means discharging the groundwater be incorporated into the design. Prior to final design, detailed hydrogeological explorations, testing and analyses will be needed to better define anticipated short-term and long-term flow rates. 6.9 Additional Geotechnical Services It is recommended that geotechnical involvement continues throughout the detail design, tender and construction phases of this project. At the time this report was prepared, loads on the abutments and piers (if any) and overall retaining systems and site design were not available. During final design, the preliminary SLS and ULS geotechnical resistances should be reviewed and revised, as appropriate, to address foundation loads and settlement tolerances. Further, since groundwater levels are well above the base of the planned roadway and the surrounding native ground is anticipated to be relatively permeable, a detailed hydrogeological study will be Report No R01 18

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23 IMPORTANT INFORMATION AND LIMITATIONS OF THIS REPORT Standard of Care: Golder Associates Ltd. (Golder) has prepared this report in a manner consistent with that level of care and skill ordinarily exercised by members of the engineering and science professions currently practising under similar conditions in the jurisdiction in which the services are provided, subject to the time limits and physical constraints applicable to this report. No other warranty, expressed or implied is made. Basis and Use of the Report: This report has been prepared for the specific site, design objective, development and purpose described to Golder by the Client. The factual data, interpretations and recommendations pertain to a specific project as described in this report and are not applicable to any other project or site location. Any change of site conditions, purpose, development plans or if the project is not initiated within eighteen months of the date of the report may alter the validity of the report. Golder can not be responsible for use of this report, or portions thereof, unless Golder is requested to review and, if necessary, revise the report. The information, recommendations and opinions expressed in this report are for the sole benefit of the Client. No other party may use or rely on this report or any portion thereof without Golder s express written consent. If the report was prepared to be included for a specific permit application process, then upon the reasonable request of the client, Golder may authorize in writing the use of this report by the regulatory agency as an Approved User for the specific and identified purpose of the applicable permit review process. Any other use of this report by others is prohibited and is without responsibility to Golder. The report, all plans, data, drawings and other documents as well as all electronic media prepared by Golder are considered its professional work product and shall remain the copyright property of Golder, who authorizes only the Client and Approved Users to make copies of the report, but only in such quantities as are reasonably necessary for the use of the report by those parties. The Client and Approved Users may not give, lend, sell, or otherwise make available the report or any portion thereof to any other party without the express written permission of Golder. The Client acknowledges that electronic media is susceptible to unauthorized modification, deterioration and incompatibility and therefore the Client can not rely upon the electronic media versions of Golder s report or other work products. The report is of a summary nature and is not intended to stand alone without reference to the instructions given to Golder by the Client, communications between Golder and the Client, and to any other reports prepared by Golder for the Client relative to the specific site described in the report. In order to properly understand the suggestions, recommendations and opinions expressed in this report, reference must be made to the whole of the report. Golder can not be responsible for use of portions of the report without reference to the entire report. Unless otherwise stated, the suggestions, recommendations and opinions given in this report are intended only for the guidance of the Client in the design of the specific project. The extent and detail of investigations, including the number of test holes, necessary to determine all of the relevant conditions which may affect construction costs would normally be greater than has been carried out for design purposes. Contractors bidding on, or undertaking the work, should rely on their own investigations, as well as their own interpretations of the factual data presented in the report, as to how subsurface conditions may affect their work, including but not limited to proposed construction techniques, schedule, safety and equipment capabilities. Soil, Rock and Groundwater Conditions: Classification and identification of soils, rocks, and geologic units have been based on commonly accepted methods employed in the practice of geotechnical engineering and related disciplines. Classification and identification of the type and condition of these materials or units involves judgment, and boundaries between different soil, rock or geologic types or units may be transitional rather than abrupt. Accordingly, Golder does not warrant or guarantee the exactness of the descriptions. June, of 2

24 IMPORTANT INFORMATION AND LIMITATIONS OF THIS REPORT Special risks occur whenever engineering or related disciplines are applied to identify subsurface conditions and even a comprehensive investigation, sampling and testing program may fail to detect all or certain subsurface conditions. The environmental, geologic, geotechnical, geochemical and hydrogeologic conditions that Golder interprets to exist between and beyond sampling points may differ from those that actually exist. In addition to soil variability, fill of variable physical and chemical composition can be present over portions of the site or on adjacent properties. The professional services retained for this project include only the geotechnical aspects of the subsurface conditions at the site, unless otherwise specifically stated and identified in the report. The presence or implication(s) of possible surface and/or subsurface contamination resulting from previous activities or uses of the site and/or resulting from the introduction onto the site of materials from off-site sources are outside the terms of reference for this project and have not been investigated or addressed. Soil and groundwater conditions shown in the factual data and described in the report are the observed conditions at the time of their determination or measurement. Unless otherwise noted, those conditions form the basis of the recommendations in the report. Groundwater conditions may vary between and beyond reported locations and can be affected by annual, seasonal and meteorological conditions. The condition of the soil, rock and groundwater may be significantly altered by construction activities (traffic, excavation, groundwater level lowering, pile driving, blasting, etc.) on the site or on adjacent sites. Excavation may expose the soils to changes due to wetting, drying or frost. Unless otherwise indicated the soil must be protected from these changes during construction. Sample Disposal: Golder will dispose of all uncontaminated soil and/or rock samples 90 days following issue of this report or, upon written request of the Client, will store uncontaminated samples and materials at the Client s expense. In the event that actual contaminated soils, fills or groundwater are encountered or are inferred to be present, all contaminated samples shall remain the property and responsibility of the Client for proper disposal. Follow-Up and Construction Services: All details of the design were not known at the time of submission of Golder s report. Golder should be retained to review the final design, project plans and documents prior to construction, to confirm that they are consistent with the intent of Golder s report. During construction, Golder should be retained to perform sufficient and timely observations of encountered conditions to confirm and document that the subsurface conditions do not materially differ from those interpreted conditions considered in the preparation of Golder s report and to confirm and document that construction activities do not adversely affect the suggestions, recommendations and opinions contained in Golder s report. Adequate field review, observation and testing during construction are necessary for Golder to be able to provide letters of assurance, in accordance with the requirements of many regulatory authorities. In cases where this recommendation is not followed, Golder s responsibility is limited to interpreting accurately the information encountered at the borehole locations, at the time of their initial determination or measurement during the preparation of the Report. Changed Conditions and Drainage: Where conditions encountered at the site differ significantly from those anticipated in this report, either due to natural variability of subsurface conditions or construction activities, it is a condition of this report that Golder be notified of any changes and be provided with an opportunity to review or revise the recommendations within this report. Recognition of changed soil and rock conditions requires experience and it is recommended that Golder be employed to visit the site with sufficient frequency to detect if conditions have changed significantly. Drainage of subsurface water is commonly required either for temporary or permanent installations for the project. Improper design or construction of drainage or dewatering can have serious consequences. Golder takes no responsibility for the effects of drainage unless specifically involved in the detailed design and construction monitoring of the system. June, of 2

25 METHOD OF SOIL CLAIFICATION The Golder Associates Ltd. Soil Classification System is based on the Unified Soil Classification System (USCS) Organic or Inorganic INORGANIC (Organic Content 30% by mass) Organic or Inorganic INORGANIC (Organic Content 30% by mass) Soil Group COARSE-GRAINED SOILS ( 50% by mass is larger than mm) Soil Group FINE-GRAINED SOILS ( 50% by mass is smaller than mm) GRAVELS (>50% by mass of coarse fraction is larger than 4.75 mm) SANDS ( 50% by mass of coarse fraction is smaller than 4.75 mm) SILTS CLAYS Type of Soil Gravels with 12% fines (by mass) Gravels with >12% fines (by mass) Sands with 12% fines (by mass) Sands with >12% fines (by mass) Type of Soil (Non-Plastic or PI and LL plot below A-Line on Plasticity Chart below) (PI and LL plot above A-Line on Plasticity Chart below) Gradation or Plasticity Poorly Graded CCCC = DD 6666 DD 1111 CCCC = (DD 3333) 22 DD 1111 xxdd 6666 <4 1 or 3 Organic Content USCS Group Symbol Group Name CLAYEY n/a GC GRAVEL 30% <6 1 or 3 SP SAND GP GRAVEL Well Graded 4 1 to 3 GW GRAVEL Below A Line Above A Line Poorly Graded n/a GM SILTY GRAVEL Well Graded 6 1 to 3 SW SAND Below A Line Above A Line Laboratory Tests Liquid Limit <50 Liquid Limit 50 Liquid Limit <30 Liquid Limit 30 to 50 Liquid Limit 50 Dilatancy Dry Strength n/a SM SILTY SAND n/a Field Indicators Shine Test Thread Diameter Rapid None None >6 mm Slow Slow to very slow Slow to very slow None None None None to Low Low to medium Low to medium Medium to high Low to medium Medium to high Dull Dull to slight Slight Dull to slight Slight to shiny Slight to shiny 3mm to 6 mm 3mm to 6 mm 3mm to 6 mm 1 mm to 3 mm ~ 3 mm 1 mm to 3 mm Toughness (of 3 mm thread) N/A (can t roll 3 mm thread) Organic Content SC USCS Group Symbol CLAYEY SAND Primary Name <5% ML SILT None to low <5% ML CLAYEY SILT Low Low to medium Medium to high 5% to 30% OL ORGANIC SILT <5% MH CLAYEY SILT 5% to 30% Low to medium 0% to Medium 30% OH ORGANIC SILT (see None High Shiny <1 mm High Note 2) CH CLAY CL CI SILTY CLAY SILTY CLAY HIGHLY ORGANIC SOILS (Organic Content >30% by mass) Peat and mineral soil mixtures Predominantly peat, may contain some mineral soil, fibrous or amorphous peat 30% to 75% 75% to 100% PT SILTY PEAT, SANDY PEAT PEAT Dual Symbol A dual symbol is two symbols separated by a hyphen, for example, GP-GM, SW-SC and CL-ML. For non-cohesive soils, the dual symbols must be used when the soil has between 5% and 12% fines (i.e. to identify transitional material between clean and dirty sand or gravel. For cohesive soils, the dual symbol must be used when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart (see Plasticity Chart at left). Note 1 Fine grained materials with PI and LL that plot in this area are named (ML) SILT with slight plasticity. Fine-grained materials which are non-plastic (i.e. a PL cannot be measured) are named SILT. Note 2 For soils with <5% organic content, include the descriptor trace organics for soils with between 5% and 30% organic content include the prefix organic before the Primary name. Borderline Symbol A borderline symbol is two symbols separated by a slash, for example, CL/CI, GM/SM, CL/ML. A borderline symbol should be used to indicate that the soil has been identified as having properties that are on the transition between similar materials. In addition, a borderline symbol may be used to indicate a range of similar soil types within a stratum. February

26 ABBREVIATIONS AND TERMS USED ON RECORDS OF BOREHOLES AND TEST PITS PARTICLE SIZES OF CONSTITUENTS Particle Soil Size Constituent Description Millimetres BOULDERS Not Applicable COBBLES Not Applicable GRAVEL SAND SILT/CLAY Coarse Fine Coarse Medium Fine Classified by plasticity Inches (US Std. Sieve Size) >300 >12 75 to to to to to to to to 3 (4) to 0.75 (10) to (4) (40) to (10) (200) to (40) <0.075 < (200) MODIFIERS FOR SECONDARY AND MINOR CONSTITUENTS Percentage by Mass Modifier >35 Use 'and' to combine major constituents (i.e., SAND and GRAVEL, SAND and CLAY) > 12 to 35 Primary soil name prefixed with "gravelly, sandy, SILTY, CLAYEY" as applicable > 5 to 12 some 5 trace PENETRATION RESISTANCE Standard Penetration Resistance (SPT), N: The number of blows by a 63.5 kg (140 lb) hammer dropped 760 mm (30 in.) required to drive a 50 mm (2 in.) split-spoon sampler for a distance of 300 mm (12 in.). Cone Penetration Test (CPT) An electronic cone penetrometer with a 60 conical tip and a project end area of 10 cm 2 pushed through ground at a penetration rate of 2 cm/s. Measurements of tip resistance (qt), porewater pressure (u) and sleeve frictions are recorded electronically at 25 mm penetration intervals. Dynamic Cone Penetration Resistance (DCPT); Nd: The number of blows by a 63.5 kg (140 lb) hammer dropped 760 mm (30 in.) to drive uncased a 50 mm (2 in.) diameter, 60 cone attached to "A" size drill rods for a distance of 300 mm (12 in.). PH: Sampler advanced by hydraulic pressure PM: Sampler advanced by manual pressure WH: Sampler advanced by static weight of hammer WR: Sampler advanced by weight of sampler and rod NON-COHESIVE (COHESIONLE) SOILS Compactness 2 Term SPT N (blows/0.3m) 1 Very Loose 0-4 Loose 4 to 10 Compact 10 to 30 Dense 30 to 50 Very Dense >50 1. SPT N in accordance with ASTM D1586, uncorrected for overburden pressure effects. 2. Definition of compactness descriptions based on SPT N ranges from Terzaghi and Peck (1967) and correspond to typical average N60 values. Term Dry Moist Field Moisture Condition Description Soil flows freely through fingers. Soils are darker than in the dry condition and may feel cool. SAMPLES AS Auger sample BS Block sample CS Chunk sample DO or DP Seamless open ended, driven or pushed tube sampler note size DS Denison type sample FS Foil sample GS Grab Sample RC Rock core SC Soil core Split spoon sampler note size ST Slotted tube TO Thin-walled, open note size TP Thin-walled, piston note size WS Wash sample SOIL TESTS w water content PL, wp plastic limit LL, wl liquid limit C consolidation (oedometer) test CHEM chemical analysis (refer to text) CID consolidated isotropically drained triaxial test 1 CIU consolidated isotropically undrained triaxial test with porewater pressure measurement 1 DR relative density (specific gravity, Gs) DS direct shear test GS specific gravity M sieve analysis for particle size MH combined sieve and hydrometer (H) analysis MPC Modified Proctor compaction test SPC Standard Proctor compaction test OC organic content test SO4 concentration of water-soluble sulphates UC unconfined compression test UU unconsolidated undrained triaxial test V (FV) field vane (LV-laboratory vane test) γ unit weight 1. Tests which are anisotropically consolidated prior to shear are shown as CAD, CAU. COHESIVE SOILS Consistency Term Undrained Shear SPT N 1,2 Strength (kpa) (blows/0.3m) Very Soft <12 0 to 2 Soft 12 to 25 2 to 4 Firm 25 to 50 4 to 8 Stiff 50 to to 15 Very Stiff 100 to to 30 Hard >200 >30 1. SPT N in accordance with ASTM D1586, uncorrected for overburden pressure effects; approximate only. 2. SPT N values should be considered ONLY an approximate guide to consistency; for sensitive clays (e.g., Champlain Sea clays), the N-value approximation for consistency terms does NOT apply. Rely on direct measurement of undrained shear strength or other manual observations. Water Content Term Description w < PL Material is estimated to be drier than the Plastic Limit. w ~ PL Material is estimated to be close to the Plastic Limit. Wet As moist, but with free water forming on hands when handled. w > PL Material is estimated to be wetter than the Plastic Limit. February

27 LIST OF SYMBOLS Unless otherwise stated, the symbols employed in the report are as follows: I. GENERAL (a) Index Properties (continued) w water content π wl or LL liquid limit ln x natural logarithm of x wp or PL plastic limit log10 x or log x, logarithm of x to base 10 lp or PI plasticity index = (wl wp) g acceleration due to gravity ws shrinkage limit t time IL liquidity index = (w wp) / Ip IC consistency index = (wl w) / Ip emax void ratio in loosest state emin void ratio in densest state ID density index = (emax e) / (emax - emin) II. STRE AND STRAIN (formerly relative density) γ shear strain (b) Hydraulic Properties change in, e.g. in stress: σ h hydraulic head or potential ε linear strain q rate of flow εv volumetric strain v velocity of flow η coefficient of viscosity i hydraulic gradient υ Poisson s ratio k hydraulic conductivity σ total stress (coefficient of permeability) σ effective stress (σ = σ - u) j seepage force per unit volume σ vo initial effective overburden stress σ1, σ2, σ3 principal stress (major, intermediate, minor) (c) Consolidation (one-dimensional) Cc compression index σoct mean stress or octahedral stress (normally consolidated range) = (σ1 + σ2 + σ3)/3 Cr recompression index τ shear stress (over-consolidated range) u porewater pressure Cs swelling index E modulus of deformation Cα secondary compression index G shear modulus of deformation mv coefficient of volume change K bulk modulus of compressibility cv coefficient of consolidation (vertical direction) ch coefficient of consolidation (horizontal direction) Tv time factor (vertical direction) III. SOIL PROPERTIES U degree of consolidation σ p pre-consolidation stress (a) Index Properties OCR over-consolidation ratio = σ p / σ vo ρ(γ) bulk density (bulk unit weight)* ρd(γd) dry density (dry unit weight) (d) Shear Strength ρw(γw) density (unit weight) of water τp, τr peak and residual shear strength ρs(γs) density (unit weight) of solid particles φ effective angle of internal friction γ unit weight of submerged soil δ angle of interface friction (γ = γ - γw) µ coefficient of friction = tan δ DR relative density (specific gravity) of solid c effective cohesion particles (DR = ρs / ρw) (formerly Gs) cu, su undrained shear strength (φ = 0 analysis) e void ratio p mean total stress (σ1 + σ3)/2 n porosity p mean effective stress (σ 1 + σ 3)/2 S degree of saturation q (σ1 - σ3)/2 or (σ 1 - σ 3)/2 qu compressive strength (σ1 - σ3) St sensitivity * Density symbol is ρ. Unit weight symbol is γ where γ = ρg (i.e. mass density multiplied by acceleration due to gravity) Notes: 1 2 τ = c + σ tan φ shear strength = (compressive strength)/2 February

28 PROJECT: LOCATION: REFER TO LOCATION PLAN HAMMER TYPE: Auto Hammer RECORD OF BOREHOLE BH-101 BORING DATE: November 3, 2016 DRILLING CONTRACTOR: London Soil Test Ltd. SHEET 1 OF 2 DATUM: GEODETIC DEPTH SCALE METRES BORING METHOD SOIL PROFILE DESCRIPTION STRATA PLOT ELEV. DEPTH (m) SAMPLES NUMBER TYPE BLOWS/0.3m ELEVATION DYNAMIC PENETRATION RESISTANCE, BLOWS/0.3m SHEAR STRENGTH Cu, kpa nat V. rem V Q - U - HYDRAULIC CONDUCTIVITY, k, cm/s WATER CONTENT PERCENT Wp W Wl ADDITIONAL LAB. TESTING INSTALLATION AND GROUNDWATER OBSERVATIONS 0 GROUND SURFACE TOPSOIL, silty; black Granular bentonite 1 FILL, sandy silt, trace gravel, with topsoil and brick pieces; brown; loose Cuttings TOPSOIL, silty; black; very loose FILL, sandy silt, some clay, trace gravel, trace topsoil; brown; very loose Granular bentonite 3 (ML) CLAYEY SILT, some sand, trace to some gravel; brown to grey at about elev m; very stiff POWER AUGER 108mm ID HOLLOW STEM (SP-SM) SAND, fine to medium, some silt; grey; compact Enc WL Nov. 30/16 Nov. 15/16 (SM) SILTY SAND, trace clay, trace to some gravel; grey; compact to very dense 7 38 MH Cuttings LDN_BHS_ GPJ GLDR_LON.GDT 14/12/16 DATA INPUT: LMK DEPTH SCALE 1 : 50 (ML) sandy CLAYEY SILT, some gravel; grey, TILL; hard (SW-SM) GRAVELLY SAND, some silt; grey; very dense --- CONTINUED NEXT PAGE /200mm Caved material LOGGED: MR CHECKED:

29 PROJECT: LOCATION: REFER TO LOCATION PLAN HAMMER TYPE: Auto Hammer RECORD OF BOREHOLE BH-101 BORING DATE: November 3, 2016 DRILLING CONTRACTOR: London Soil Test Ltd. SHEET 2 OF 2 DATUM: GEODETIC DEPTH SCALE METRES BORING METHOD SOIL PROFILE DESCRIPTION STRATA PLOT ELEV. DEPTH (m) SAMPLES NUMBER TYPE BLOWS/0.3m ELEVATION DYNAMIC PENETRATION RESISTANCE, BLOWS/0.3m SHEAR STRENGTH Cu, kpa nat V. rem V Q - U - HYDRAULIC CONDUCTIVITY, k, cm/s WATER CONTENT PERCENT Wp W Wl ADDITIONAL LAB. TESTING INSTALLATION AND GROUNDWATER OBSERVATIONS CONTINUED FROM PREVIOUS PAGE --- (SW-SM) GRAVELLY SAND, some silt; grey; very dense POWER AUGER 108mm ID HOLLOW STEM (ML) SANDY SILT, some clay, some gravel; grey, TILL; very dense (SW-SM) GRAVELLY SAND, fine to coarse, some silt, with cobbles from about elev m to about elev m; grey; very dense Caved material Piezometer 13 (CL) sandy SILTY CLAY, some gravel; grey, TILL; hard END OF BOREHOLE Groundwater encountered at about elev m during drilling on November 3, Water level measured in piezometer at elev m on November 15, Water level measured in piezometer at elev m on November 30, LDN_BHS_ GPJ GLDR_LON.GDT 14/12/16 DATA INPUT: LMK DEPTH SCALE 1 : 50 LOGGED: CHECKED: MR

30 PROJECT: LOCATION: REFER TO LOCATION PLAN HAMMER TYPE: Auto Hammer RECORD OF BOREHOLE BH-102 BORING DATE: November 2, 2016 DRILLING CONTRACTOR: London Soil Test Ltd. SHEET 1 OF 2 DATUM: GEODETIC DEPTH SCALE METRES BORING METHOD SOIL PROFILE DESCRIPTION STRATA PLOT ELEV. DEPTH (m) SAMPLES NUMBER TYPE BLOWS/0.3m ELEVATION DYNAMIC PENETRATION RESISTANCE, BLOWS/0.3m SHEAR STRENGTH Cu, kpa nat V. rem V Q - U - HYDRAULIC CONDUCTIVITY, k, cm/s WATER CONTENT PERCENT Wp W Wl ADDITIONAL LAB. TESTING INSTALLATION AND GROUNDWATER OBSERVATIONS 0 PAVEMENT SURFACE ASPHALT FILL, gravelly sand, crushed; brown TOPSOIL, silty, trace gravel, with cinders; black; loose FILL, sand, some topsoil, trace gravel; black; very loose (ML) CLAYEY SILT, some sand, trace gravel; brown; stiff Enc WL POWER AUGER 108mm ID HOLLOW STEM (ML) SILT, trace to some sand, trace clay; brown to grey at about elev m; compact (SP-SM) SAND, fine to medium, some silt; grey; compact MH (SM) SILTY SAND, some clay, trace gravel; grey; dense to very dense 8 44 MH LDN_BHS_ GPJ GLDR_LON.GDT 14/12/16 DATA INPUT: LMK DEPTH SCALE 1 : 50 (SP-SM) SAND, fine to medium, some silt; grey; very dense (ML) clayey SANDY SILT, trace to some gravel; grey, TILL; very dense --- CONTINUED NEXT PAGE /279mm Enc WL Groundwater encountered at about elev m and elev m during drilling on November 2, LOGGED: MR CHECKED:

31 PROJECT: LOCATION: REFER TO LOCATION PLAN HAMMER TYPE: Auto Hammer RECORD OF BOREHOLE BH-102 BORING DATE: November 2, 2016 DRILLING CONTRACTOR: London Soil Test Ltd. SHEET 2 OF 2 DATUM: GEODETIC DEPTH SCALE METRES BORING METHOD SOIL PROFILE DESCRIPTION STRATA PLOT ELEV. DEPTH (m) SAMPLES NUMBER TYPE BLOWS/0.3m ELEVATION DYNAMIC PENETRATION RESISTANCE, BLOWS/0.3m SHEAR STRENGTH Cu, kpa nat V. rem V Q - U - HYDRAULIC CONDUCTIVITY, k, cm/s WATER CONTENT PERCENT Wp W Wl ADDITIONAL LAB. TESTING INSTALLATION AND GROUNDWATER OBSERVATIONS CONTINUED FROM PREVIOUS PAGE POWER AUGER 108mm ID HOLLOW STEM (ML) clayey SANDY SILT, trace to some gravel; grey, TILL; very dense 12 31/51mm END OF BOREHOLE /180mm LDN_BHS_ GPJ GLDR_LON.GDT 14/12/16 DATA INPUT: LMK DEPTH SCALE 1 : 50 LOGGED: CHECKED: MR

32

33 Size of openings, inches U.S.S. Sieve Size, meshes/inch /4 1/2 3/ PERCENT FINER THAN GRAIN SIZE, mm Cobble Size coarse fine GRAVEL SIZE coarse medium SAND SIZE fine SILT AND CLAY LEGEND SYMBOL BOREHOLE BH-101 BH-102 SAMPLE 7 8 ELEV (m) LDN_GSD GLDR_LDN.GDT 30/11/16 PROJECT TITLE GEOTECHNICAL INVESTIGATION ADELAIDE STREET AT CANADIAN PACIFIC RAIL MILE GALT SUBDIVISION LONDON, ONTARIO GRAIN SIZE DISTRIBUTION SILTY SAND PROJECT No. DRAWN CHECK LMK Nov 30/16 FILE No. SCALE N/A FIGURE R01002 REV. 2

34 Size of openings, inches U.S.S. Sieve Size, meshes/inch /4 1/2 3/ PERCENT FINER THAN GRAIN SIZE, mm Cobble Size coarse fine GRAVEL SIZE coarse medium SAND SIZE fine SILT AND CLAY LEGEND SYMBOL BOREHOLE BH-102 SAMPLE ELEV (m) LDN_GSD GLDR_LDN.GDT 30/11/16 PROJECT TITLE GEOTECHNICAL INVESTIGATION ADELAIDE STREET AT CANADIAN PACIFIC RAIL MILE GALT SUBDIVISION LONDON, ONTARIO GRAIN SIZE DISTRIBUTION SILT PROJECT No. DRAWN CHECK LMK Nov 30/16 FILE No. SCALE N/A FIGURE R01003 REV. 3

35 Golder Associates Ltd. 309 Exeter Road, Unit #1 London, Ontario, N6L 1C1 Canada T: +1 (519)