GEOTECHNICAL REPORT LA GUARDE CREEK BRIDGE CROSSING, SIPHON CREEK ROAD, 40 KM NORTHEAST OF FORT ST. JOHN, B.C. Prepared for

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1 GEOTECHNICAL REPORT LA GUARDE CREEK BRIDGE CROSSING, SIPHON CREEK ROAD, 40 KM NORTHEAST OF FORT ST. JOHN, B.C. Prepared for B.C. MINISTRY OF TRANSPORTATION AND INFRASTRUCTURE PRINCE GEORGE, B.C. Prepared by th AVENUE PRINCE GEORGE, B.C., V2N 1B2 Phone: Fax: PROJECT No. K-4274 January 18, 2016

2 TABLE OF CONTENTS Page No. 1.0 INTRODUCTION SITE AND PROJECT DESCRIPTION GEOLOGICAL BACKGROUND Surficial Geology Bedrock Geology Review of Aerial Photographs SITE INVESTIGATION SUBSURFACE CONDITIONS Bridge Foundations Existing Pavement Structure DISCUSSIONS AND RECOMMENDATIONS Bridge Foundations Bridge End Fill Pavement Structure Aggregates and Fill CONSTRUCTION REVIEW CLOSURE 15

3 APPENDICES APPENDIX A Site Location Plan Drawing 4274-A1 Site Plan and Profile Drawing 4274-A2 APPENDIX B Summary Logs Materials Classification Legend 6 pages 1 page APPENDIX C Transition Detail: Existing to New Road Structure Plate 4274-C1 Typical Embankment Widening Detail Plate 4274-C2 APPENDIX D Site Photographs Plates 4274-P1 to P2

4 1.0 INTRODUCTION The British Columbia Ministry of Transportation and Infrastructure (BCMoT) is planning to replace an existing multiplate culvert crossing of La Guarde Creek on Siphon Creek Road with a 28 m long, clear span bridge. The crossing is located about 40 km northeast of Fort St. John, B.C., and is accessed by the Rose Prairie Road, then about 22 km east on Cecil Lake Road and 30 km north on Siphon Creek Road. The site location is shown on Drawing 4274-A1, in Appendix A. BCMoT commissioned GeoNorth Engineering Ltd. to carry out a geotechnical investigation for design and construction of the proposed bridge foundations and approaches. The scope of our work is outlined in our proposal dated September 29, 2015 to Mr. Brent Case, P.Eng. of BCMoT. Mr. Case authorized us to proceed with the work in an dated September 30, Conceptual design sketches by BCMoT show that the new bridge will be a 28 m long, 12 m wide two lane bridge. At the time of this report, design of the proposed bridge had not been carried out but we understand the structure will likely use precast concrete or steel girders and precast concrete abutments placed on pile or spread footing foundations. A site plan showing the existing crossing is on Drawing 4274-A2, in Appendix A. This report presents the results of our site investigation, and provides geotechnical recommendations for design and construction of the proposed bridge foundations and approaches. Page 1 of 17

5 2.0 SITE AND PROJECT DESCRIPTION The present crossing consists of a 3.6 m diameter, 28.3 m long, structural plate corrugated steel pipe (SPCSP). The upstream (south) side of the SPCSP was recently damaged and about 12 m length of pipe was removed. An emergency repair was made to the road consisting of rip-rap slope protection, a short concrete locking block wall on the south side and fill placed out over the north side to shift the road north, away from the eroded upstream bank. The road is currently open for singe-lane traffic only. Site plans and cross section profiles dated August 2015 by McElhanney Consulting Services Ltd., survey consultants for the project, show there is between 2.0 to 2.5 m of soil cover over the culvert. The pipe inlet and outlet are at elevations and m, respectively. The lowest point of the creek bed upstream of the culvert is at about elevation m, lower than the culvert inlet and the high water mark is at approximately elevation m. The site plans show an existing beaver dam located near the original culvert inlet. The cause of the culvert failure is unknown, but might have been due to buoyant uplift forces caused by air inside the pipe when it became partially blocked by the beaver dam and other debris. Other possible causes include joint separation from differential settlement or poor construction, piping or scour below the culvert inlet due to poorly compacted backfill, inadequate erosion protection, or holes in the pipe from corrosion. The existing road consists of two 3.6 m wide, paved lanes and about 0.5 m wide gravel shoulders, for a total width of about 8.2 m. The bridge surface will likely consist of two 3.6 m wide lanes, 2.0 m wide shoulders and an allowance for bridge parapets, for a total width of about 12 m. To accommodate an increased road width, we understand the grade of the road at the proposed bridge crossing will be slightly lowered. Conceptual design sketches show the existing creek channel will be moved slightly east and the channel skew angle relative to the bridge will o o be increased from 29 to 35. Overview photos of the site are shown on Plates 4274-P1 and P2 in Appendix D. Page 2 of 17

6 3.0 GEOLOGICAL BACKGROUND To obtain geological background information for this project, we reviewed published surficial and bedrock geological maps and reports, and aerial photographs. 3.1 Surficial Geology Map 1460A, by Geological Survey of Canada, at a scale of 1:250,000, shows the area along the Doig River valley is underlain by deposits from Glacial Lake Peace and the uplands on each side of the valley are underlain by drumlinized till. The site, located near the south edge of the Doig River valley at about elevation 670 m, is well below the level of Glacial Lake Peace, shown at about elevation 700 m on the map. Glacial lake sediments typically consist of layered silt, clay and fine grained sand. Glacial till is typically a heterogeneous mixture of sand to cobble size particles in a silt and clay matrix, deposited from below glacial ice that once covered the area. 3.2 Bedrock Geology Map NO-10-G, by Geological Survey of Canada, at a scale of 1:500,000, shows that bedrock in the area is Lower to Upper Cretaceous in age. The bedrock is identified as fine clastic sedimentary rocks including dark grey marine shale, siltstone and sandstone of the Fort St. John Group and the Kotaneelee Formation. 3.3 Review of Aerial Photographs We reviewed digital aerial photographs available from GeoBC from flight lines 30BCB95008 dated 1995, 15BCB97013 dated 1997, and 15BCC05124 dated The photos show the project area on flat terrain that has a mottled surface and dendritic drainage patterns, characteristic of areas underlain by glacial lake sediments. Starting just upstream of the bridge crossing, La Guarde Creek channel has cut into the flat lying glacial lake sediments, and created Page 3 of 17

7 a steep-sided, incised draw that becomes progressively deeper and with more unstable sidewalls to the confluence with Doig River. Most of the surrounding land is cultivated farmland or tree covered. The photos show Siphon Creek Road, the culvert crossing at La Guarde Creek and ponded water at the culvert inlet. In the 1995 photos the ponded water can be seen extending more than 1 km upstream. In the later photos, ponding is mostly isolated to a marshy area directly upstream of the culvert. 4.0 SITE INVESTIGATION On October 7 and 8, 2015, personnel from our office observed soil and groundwater conditions in two drill holes, designated DH15-1 and 2, that were advanced to 27.2 and 24.4 m depth, respectively, on each side of the crossing. The holes were advanced by Peace Drilling and Research Ltd. of Fort St. John using a truck-mounted rig and solid-stem augers. Sampling was carried out at regular intervals using Standard Penetration Tests (SPTs) (ASTM D1568) and Shelby tubes (ASTM D1587). We also collected samples from the auger flights and carried out shear vane (ASTM D2573) tests in the drill holes. Drill hole locations were measured from site landmarks and elevations were surveyed using an engineering level and rod. The locations of the drill holes are shown on Drawing 4274-A1, in Appendix A. Drill hole elevations were referenced to the culvert inlet and outlet elevations and are shown on the drill hole logs. A cross section profile showing the existing centre line profile and stick logs of subsurface conditions are also shown on Drawing 4274-A1. We logged soil and groundwater conditions encountered in the drill holes as they were advanced and collected representative samples for laboratory tests and classification. Selected samples were tested in our laboratory for natural moisture content, Atterberg plasticity limits (ASTM D4318) and grain size distribution. Drill hole summary logs describing subsurface conditions and showing the laboratory test results are in Appendix B. An explanation of terms and symbols used on the logs is also included in Appendix B. Page 4 of 17

8 The SPT involves driving a standard 50 mm diameter sampling tube into the bottom of the drill hole using a 62 kg weight, free-falling from a height of 760 mm. The SPT provides information on the relative density of the soil and allows a sample to be collected. Shelby tube sampling involves pushing a 75 mm diameter thin-walled tube into the ground to obtain a relatively undisturbed sample. Field shear vane tests involve pushing a four-bladed vane into undisturbed soil below the bottom of the drill hole and rotating it from surface while measuring the torque required to shear a cylindrical surface. The shear vane is used to measure the undrained shear strength of the soil. 5.0 SUBSURFACE CONDITIONS 5.1 Bridge Foundations The drill holes encountered similar conditions consisting of the following soil units: Unit 1 - Loose to compact granular fill with trace to some fines, over Unit 2 - Stiff to very stiff silty clay fill with a variable amount of sand and gravel, over Unit 3 - Varved and layered, soft to stiff clay and silt, over Unit 4 - Very stiff, silty clay till with a trace of sand and gravel, over Unit 5 - Extremely weak to very weak siltstone bedrock. Unit 1, the granular fill was encountered in both drill holes to about 0.9 m depth. The granular fill in DH15-1 consists of loose sandy gravel used to shift the road north. In DH15-2, the granular fill consists of compact sand and gravel used in the existing pavement structure. The existing pavement structure is described in the following section. Unit 2, the silty clay fill was encountered below Unit 1 in both drill holes to 3.1 and 5.5 m depth, respectively. Field shear vane and pocket penetrometer tests indicate the strength of the silty clay fill decreases with depth with an undrained shear strength between 75 and 125 kpa. Laboratory Atterberg limit tests, used to define the plasticity of the soil and to infer its Page 5 of 17

9 general engineering characteristics, were carried out on four samples of the silty clay fill. The results indicate the fill has properties of intermediate to high plasticity, with a plastic limit of about 24% and a liquid limit between 45% and 52%. The plastic limit defines the moisture content at which soil behaviour changes from a semisolid to a plastic material, and the liquid limit defines the moisture content at which soil behaviour changes from a plastic material to that of a viscous liquid. The natural moisture content of the silty clay fill is typically near the plastic limit. Unit 3, the varved and layered clay and silt was encountered below Unit 2 to 16.5 m depth in DH15-1 and 17.5 m depth in DH15-2. The unit is from Glacial Lake Peace and contains frequent gypsum crystals throughout the deposit. The undrained shear strength of the natural clay and silt for the full depth of the unit is between about 25 and 60 kpa based on field shear vanes. Atterberg limit tests indicate the clay has properties of high plasticity, with a plastic limit of about 26% and a liquid limit between 58% and 71%. The silt layers are low to intermediate plasticity, with a plastic limit of about 22% and a liquid limit between 33% and 37%. The natural moisture content of the clay is typically higher than the plastic limit but lower than the liquid limit and the natural moisture content of the silt is typically near the liquid limit. Over-consolidation ratio (OCR) is an important geotechnical parameter to evaluate the potential for foundation settlement. It is defined as the preconsolidation pressure divided by the present effective stress state of the soil. Soil preconsolidation pressure is the maximum stress that the soil has previously experienced and can be higher than the existing stress conditions due to changes in groundwater levels, erosion of materials that previously covered an area, or construction of a preload fill. Foundation loads that do not cause the effective stress in the underlying soil to exceed the preconsolidation pressure will result in less settlement than loads that exceed the preconsolidation pressure. A correlation based on normalized field vane strength to OCR shows the natural clay and silt is over-consolidated to about 8.5 m depth, with an OCR between 1.3 and 5, and normally to slightly over consolidated below 8.5 m depth, with an OCR between 1 and 1.3. This indicates Page 6 of 17

10 that the natural clay and silt at depth has not experienced significantly more vertical stress than the existing overburden pressure and will therefore be susceptible to significantly more settlement than if the deposit was over-consolidated. Unit 4, the clay till was encountered below Unit 3 in DH15-1 and extends to 18.6 m depth. The clay till has properties of intermediate plasticity, with a plastic limit of 19% and a liquid limit of 37%. The natural moisture content of the till is about 15%. The undrained shear strength of the clay till is about 100 kpa based on pocket penetrometer tests. Unit 5, the siltstone bedrock was encountered below Unit 4 to the end of both drill holes at 27.2 m and 24.4 m depth, respectively. The bedrock was easily penetrated with augers during drilling. The siltstone bedrock is poorly lithified, extremely weak and highly weathered in the top 1 to 3 m depth. Below 1 to 3 m depth the bedrock has isolate shale layers, is very weak and moderately weathered. We estimate the uniaxial compressive strength of the siltstone is between 1 and 5 MPa. No groundwater seepage was observed in the drill holes. 5.2 Existing Pavement Structure DH15-2, located at the south side of the east approach, generally encountered the following pavement structure: 75 mm of Asphalt Pavement, over 775 mm of Base Coarse and Subbase, over Geogrid and non-woven geotextile, over Clay subgrade Page 7 of 17

11 The base coarse and subbase generally consists of a mixture of gravel and sand sized particles with between 7% and 13% fines. The aggregate is typically less than 75 mm diameter and is rounded to subangular. The subgrade consists of very stiff, intermediate to high plastic, silty clay fill with a variable amount of sand and gravel. 6.0 DISCUSSIONS AND RECOMMENDATIONS The crossing is generally underlain by a significant thickness of embankment fill, over glaciolacustrine sediments from Glacial Lake Peace, over a thin layer of gravelly clay till below one side of the crossing, over bedrock at between 17.5 and 18.6 m depth. The natural soft to firm clay and silt has low bearing capacity, high potential for settlement and is highly susceptible to frost heave caused by the development of ice lenses. The glacial lake sediments in the region are also known to contain minerals that cause it to shrink and swell in response to changes in moisture content. The existing embankment fill is susceptible to differential settlement and is not suitable for support of spread footing foundations. Given the relatively weak, compressible soil conditions, the shrink and swell potential of the soil, and the significant thickness of existing fill, we recommend against using spread footing foundations to support the proposed bridge. Instead, we recommend supporting the bridge structure on driven pile foundations end-bearing on the relatively shallow bedrock, as described below. The following recommendations are based on the necessary assumption that ground conditions encountered in the drill holes are representative of conditions elsewhere below the project site. The bedrock surface appears to be relatively flat but could be deeper than encountered in the drill holes. Please contact our office for additional recommendations if conditions encountered during construction differ in any way from those described in this report. Page 8 of 17

12 6.1 Bridge Foundations Steel pipe piles driven to the bedrock will be suitable for support of the proposed bridge structure. The piles will gain most of their capacity from end-bearing in the bedrock Axial Capacity To estimate bridge foundation loads we assume the bridge will be constructed using Type 2 concrete box stringers, concrete abutments, and a 100 mm thick concrete overlay. We also assume the bridge will be designed to carry BCL-625 live loads. Based on these assumptions we estimate the ultimate limit states (ULS) live and dead loads will be about 7,000 kn at each abutment. Based on information from the drill holes, we carried out preliminary pile capacity analyses using several methods outlined in the Canadian Foundations Engineering Manual (CFEM) (Canadian Geotechnical Society, 2006). The methods use undrained shear strength, effective stress and SPT N values. BCMoT s Supplement to the Canadian Highway Bridge Design Code specifies a geotechnical resistance factor of 0.35 for design based on SPT information. Assuming each abutment will have six piles connected to a pile cap, each pile will need to have a geotechnical resistance of about 1,200 kn and the required ultimate geotechnical resistance of 3,400 kn. Pile capacity will depend largely on end-bearing resistance, as well as shaft friction, the pile stiffness (wall thickness and length), the energy of the pile driving equipment, and the penetration resistance at end-of-driving. We analysed the estimated embedment depth and driveability of 610 mm and 762 mm diameter open-ended steel pipe piles. The piles are likely to penetrate the siltstone bedrock between 1 and 3 m. We analysed pile driveability using the computer program GRLWEAP (GRLWEAP, 2005), assuming end bearing in the bedrock at about elevation 658 m. A summary of the analyses is shown in Table 1, below. Page 9 of 17

13 Table 1, Summary of Pile Driving Analyses for 610 and 762 mm Diameter Open-End Pipe Piles 610 mm Diameter, 12.7 mm Wall Thickness 762 mm Diameter, 12.7 mm Wall Thickness Factored Geotechnical Resistance 1,200 kn 1,500 kn Anticipated Tip Elevation 657 m 657 m Driving Energy 120 kj 160 kj Penetration Resistance 250 blows/m 260 blows/m Maximum Pile Stress 250 MPa 280 MPa Based on the estimated maximum pile stress we recommend using piles manufactured with Grade 3 steel (ASTM A252). Use an inside-fit cutting shoe to reduce the potential for damage to the tip of the pile while driving into the bedrock. We recommend the axial capacity be confirmed using Pile Driving Analysis (PDA) (ASTM D4945) method Case Pile Wave Analysis Program (CAPWAP) if conditions do not appear to be straightforward or if there are any concerns regarding the efficiency of the hammer energy being delivered to the pile, or if there are any indications of damage to the pile. Information on pile capacity from a PDA with a CAPWAP will also allow the use of a geotechnical resistance factor of 0.5 (BCMOT, 2007). Allow at least 72 hours between pile installation and testing. known. We recommend that additional analyses be carried out once bridge design and loads are Pile Settlement Pile settlement occurs primarily due to the transfer of stress to the soil and elastic shortening of the pile. Settlement in the granular soil around the pile will generally occur as the pile begins to carry loads during construction of the bridge, although a small portion of the settlement will occur as plastic creep over time. Page 10 of 17

14 We estimate the settlement of the soil around and below a pile using methods described in the CFEM. Using specified loads of 1,000 and 1,400 kn for 610 and 762 mm diameter piles, respectively, with the load evenly distributed between shaft and end bearing resistance, both pile sizes will settle less than 5 mm. Differential settlement between each abutment could be as high as the total settlement Lateral Pile Capacity The abutment will be subjected to lateral loads from earth pressures and vehicle breaking. These loads generally act along the long axis of the bridge and will likely be transmitted through bridge girders to the opposite abutment wall and bridge end fill, resulting in no significant loads being transferred to the piles. We recommend additional analyses be carried out once the bridge design loads are known Seismic Design Considerations The 2012 British Columbia Building Code defines the Site Classification for Seismic Site Response, Table A, which is based on the soil conditions to a depth of 30 m. Based on our drill hole observations, we estimate the silty clay and clayey silt underlying the site has an average undrained shear strength between 50 and 100 kpa, and the Site Classification for Seismic Site Response is no worse than Site Class D, as defined in Table A. Based on our observations that the site is underlain by a thick deposit of soft to stiff silty clay and clayey silt over bedrock, we recommend the following Canadian Highway Bridge Design Code (2014) seismic hazard values for the project: Site Class Sa(0.2) Sa(0.5) Sa(1.0) Sa(2.0) Sa(10.0) F(0.2) F(0.5) PGA PGV D g g g g g g g Note: Determined for a 2% in 50 year ( per annum) probability of exceedence. Page 11 of 17

15 6.2 Bridge End Fill BCMoT s Standard Specifications for Highway Construction (BCMoT, 2011) requires bridge end fill (BEF) extend a distance of 8 m from the bridge abutment with a 1.5 Horizontal to 1.0 Vertical (1.5H:1V) backslope. Prior to placing BEF, remove organic material and soft, wet or deleterious soil and compact the subgrade surface to at least 98% Standard Proctor Density (SPD) (ASTM D698). Place BEF in layers not exceeding 150 mm thickness and compact each layer to at least 100% SPD. 6.3 Pavement Structure The recommended base and subbase thicknesses are intended to provide for a long first cycle life and long-term support for moderate axle loads, provided the pavement surface is rehabilitated at appropriate intervals. We recommend the following pavement structure to provide similar strength to that of the existing: 75 mm of Asphalt Pavement (Class 1), over 200 mm of 25 mm Well Graded Base (WGB), over 600 mm of Select Granular Subbase (SGSB), over Biaxial geogrid, over Nonwoven geotextile, over A prepared subgrade. Construct all components of the new pavement structure with at least a 2% crossfall to the outside. Where the new structure ties into the existing structure we recommend using a saw cut between 20 and 30 from perpendicular to road centreline. At the face of the saw cut, leave an undisturbed width of existing crushed base 500 mm wide, then begin excavation of a transition slope of 4 Horizontal to 1 Vertical (4H:1V) to accommodate the new pavement structure thickness. A conceptual transition detail are shown on Drawing 4274-C1, in Appendix C. Page 12 of 17

16 Use a medium weight nonwoven geotextile that meets or exceeds the following Minimum Average Roll Values (MARV): Minimum Grab Tensile Strength (ASTM D4632), 900 N Minimum Puncture 50% or More Elongation (ASTM D6241), 2.3 kn Minimum Trapezoidal Tear (ASTM D4533), 350 N Apparent Opening Size (ASTM D4751), 0.2 mm ± 0.02 mm Use a polypropylene biaxial geogrid that meets or exceeds the following values: Minimum Tensile Strength in Machine 5% Strain (ASTM D6637), 11 KN/m Minimum Tensile Strength in Cross Machine 5% Strain (ASTM D6637), 19 KN/m Aperture Size, 15 to 35 mm Minimum Flexural Stiffness (ASTM D5732), 750 mg-cm 6.4 Aggregates and Fill Base, Subbase and Bridge End Fill Three material types are specified for construction of the pavement structure and bridge embankment noted above: 25 mm Well Graded Base (WGB), Select Granular Subbase (SGSB), Bridge End Fill (BEF). Use material that meets BCMoT s specifications noted in Section 202 of the 2012 Standard Specifications for Highway Construction. Page 13 of 17

17 6.4.2 Highway Embankment and Subgrade Fill We recommend constructing the embankment using mineral soil free of organic and deleterious material and containing less than 15% by volume of rock larger than 150 mm. Granular material excavated from the existing embankment at the start and end of the project and from both new bridge end-fill areas, can be reused as embankment fill. We recommend using embankment fill slopes no steeper than 2H:1V for granular fill and slopes no steeper than 3H:1V for cohesive embankment fill and the natural clay and silt. The stream channel below the bridge may require revetment to prevent on-going channel erosion from undermining the slopes leading up to the bridge abutments. In some areas the surface of the existing embankment will be covered with winter road sand, grass, and brush. We recommend stripping the surface of the embankment to expose compact mineral soil. Key new fill into the existing embankment using benches. Cut the benches into the existing embankment using a minimum bench width of 1.5 m and a maximum height of 1.2 m. If suitable, the material from the bench can be incorporated into the new embankment. Slope the bench surface at a gradient of 2% towards the outside slope face. A conceptual cross section showing this detail is on Drawing 4274-C2, in Appendix C. Place the embankment fill in thin, uniform layers and compact each layer to at least 95% SPD, and to at least 100% SPD within 300 mm of the top of subgrade, at a moisture content within 2% of optimum. The maximum layer thickness will depend on several factors, including compactor type, size and energy, and the soil type and moisture content, but do not use a layer thickness more than 200 mm. Add water and dry the fill as necessary to attain the specified density and moisture content. Where the embankment is relatively narrow between about Stations and , if necessary, construct the embankment slopes no steeper than 3H:1V by widening the base as described above. Protect the toe of the slope from erosion as required for that length of slope below the projected 200 year return period flood level. Page 14 of 17

18 7.0 CONSTRUCTION REVIEW We recommend that we review final design drawings to confirm that the intent of our recommendations have been applied, that the recommendations in this report are appropriate and that sufficient geotechnical investigation has been carried out. We recommend that an experienced geotechnical engineer, or their designate, review critical aspects of the project to confirm that soil conditions are as expected and that construction materials, their placement and their level of compaction are as specified. If soil conditions or construction materials are different than expected, we can provide additional recommendations to address the actual conditions. We consider the following geotechnical aspects of the work as being critical to the project: Removal of soft or deleterious soil below areas of fill, Gradation, durability, placement and compaction of fill, and Pile installation, and whether a PDA with a CAPWAP are required. 8.0 CLOSURE This report was prepared by GeoNorth Engineering Ltd. for the use of B.C. Ministry of Transportation and Infrastructure and their consultants. The material in it reflects GeoNorth Engineering s judgement in light of the information available to us at the time of preparation. Any use which Third Parties make of this report, or any reliance on decisions to be made based on it, are the responsibility of such Third Parties. GeoNorth Engineering Ltd. accepts no responsibility for damages, if any, suffered by any third party as a result of decisions made or actions based on this report. Page 15 of 17

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20 REFERENCES B.C. Ministry of Transportation and Infrastructure, Bridge Standards and Procedures Manual, Volume 1, Supplement to CHBDC S6-06. B.C. Ministry of Transportation and Infrastructure, Standard Specifications for Highway Construction, Volume 1. th Canadian Geotechnical Society, Canadian Foundation Engineering Manual, 4 Edition. Canadian Standards Association, CSA-S6 - Canadian Highway Bridge Design Code. GRLWEAP Wave Equation Analysis of Pile Driving, [Computer Software], Cleveland, Ohio, USA, Pile Dynamics, Inc. McElhanney Consulting Services Ltd., Plan & Profiles, Siphon Creek Road, La Guarde Creek. Drawing NR-XXX-101, August 6, Submitted to British Columbia Ministry of Transportation and Infrastructure. Natural Resources Canada (2015): Determine 2015 Seismic Hazard Values for Nation Building Code and Canadian Highway Bridge Design Code, URL< nrcan.gc.ca/hazard-alea/interpolat/index_2015-eng.php>, November Page 17 of 17

21 A P P E N D I X A

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24 A P P E N D I X B

25 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) DRILLING DETAILS Reviewed by: 7 SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Lt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO RECOVERY (%) 23 SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION GRAVEL, sandy, trace fines, loose, brown, damp (FILL). CLAY, silty, trace gravel, trace sand, stiff to very stiff, intermediate plasticity, brown, rust staining, MC<PL (FILL). - between 1.2 and 1.8m, some gravel. 0.91m Date(s) Drilled: Oct. 7, 2015 Driller: Jesse Rushton Drill Make/Model: Truck Mounted Drilling Method: Solid Stem Augers CLASSIFICATION GW- GM CL Drill Hole #: DH15-1 Drilling Company: Peace Drilling COMMENTS TESTING Drillers Estimate {G % S % F %} Sieve (Sa#1) G:59% S:34% F:7% Atterberg (Sa#3): PL:24% LL:47% ELEVATION (m) CLAY, silty, varved, firm, high plasticity, grey, occasional gypsum crystals, MC>PL. - between 3.0 and 3.8m, frequent gypsum crystals. 3.05m Atterberg (Sa#7): PL:28% LL:71% MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample 7 6 A-Auger C-Core G-Grab V-Vane S-Split Spoon O-Odex (air rotary) W-Wash (mud return) T-Shelby Tube - between 5.8 and 6.4m, layered with low plasticity, clayey silt. CH Atterberg (Sa#11): PL:26% LL:70% Final Depth of Hole: 27.2 m Depth to Top of Rock: 18.6 m Page 1 of 3

26 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) 10 DRILLING DETAILS Reviewed by: SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Lt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO RECOVERY (%) SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION CLAY, silty, varved, firm, high plasticity, grey, occasional gypsum crystals, MC>PL. (continued) Driller: Jesse Rushton Drill Make/Model: Truck Mounted CLASSIFICATION Drill Hole #: DH15-1 Date(s) Drilled: Oct. 7, 2015 Drilling Company: Peace Drilling Drilling Method: Solid Stem Augers COMMENTS TESTING Drillers Estimate {G % S % F %} ELEVATION (m) CLAY, and SILT, trace fine grained sand, layered, soft, intermediate plasticity, grey, MC>PL, slow dilatancy. 12.8m CLAY, silty, varved, firm, high plasticity, grey, MC>PL m CL- ML Atterberg (Sa#15): PL:22% LL:37% at 14.6m, 20mm thick layer of medium grained, wet sand. CH 663 MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample S-Split Spoon O-Odex (air rotary) A-Auger C-Core G-Grab V-Vane W-Wash (mud return) T-Shelby Tube CLAY, silty, trace to some gravel, trace sand, very stiff, intermediate plasticity, brown-grey, MC<PL (TILL). BEDROCK, siltstone, poorly lithified, extremely weak (R0), highly weathered, light grey m 18.59m CL Atterberg (Sa#17): PL:19% LL:37% Sieve (Sa#17) G:24% S:15% F:61% Final Depth of Hole: 27.2 m Depth to Top of Rock: 18.6 m Page 2 of 3

27 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) 20 DRILLING DETAILS Reviewed by: SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Lt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO RECOVERY (%) SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION BEDROCK, siltstone, poorly lithified, extremely weak (R0), highly weathered, light grey. (continued) Date(s) Drilled: Oct. 7, 2015 Driller: Jesse Rushton Drill Make/Model: Truck Mounted Drilling Method: Solid Stem Augers CLASSIFICATION Drill Hole #: DH15-1 Drilling Company: Peace Drilling COMMENTS TESTING Drillers Estimate {G % S % F %} ELEVATION (m) 21 Refusal, 50 for 1" below 21.0m, isolated shale layers, very weak (R1), moderately weathered, dark grey BR Refusal, 50 for 4" MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample A-Auger C-Core G-Grab V-Vane S-Split Spoon Refusal, 50 for 3" O-Odex (air rotary) W-Wash (mud return) T-Shelby Tube End of drill hole at 27.2m. No seepage encountered. 27.2m Final Depth of Hole: 27.2 m Depth to Top of Rock: 18.6 m Page 3 of 3

28 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) DRILLING DETAILS Reviewed by: SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Rt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO RECOVERY (%) 36 SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION ASPHALT. SAND, and GRAVEL, some fines, compact, brown, damp (FILL). - at 0.85m, geogrid over nonwoven geotextile. CLAY, silty, trace gravel, trace sand, stiff to very stiff, intermediate to high plasticity, brown, rust staining, MC>PL (FILL). - at 0.9m, a layer of geogrid and geotextile. - at 1.5m, organic soil layer about 5cm thick. 0.08m AP 0.85m Date(s) Drilled: Oct. 8, 2015 Driller: Jesse Rushton Drill Make/Model: Truck Mounted Drilling Method: Solid Stem Augers CLASSIFICATION GM1 Drill Hole #: DH15-2 Drilling Company: Peace Drilling COMMENTS TESTING Drillers Estimate {G % S % F %} Sieve (Sa#1) G:40% S:47% F:13% Atterberg (Sa#4): PL:25% LL:52% ELEVATION (m) between 2.7 and 3.5m, trace to some organic soil content. CL- CH below 4.3m, isolated gypsum crystals. Atterberg (Sa#6): PL:23% LL:45% Atterberg (Sa#8): 5.49m CLAY, silty, varved, soft, high plasticity, PL:25% LL:49% grey, isolated gypsum crystals, MC>PL. PP=30 to 50 MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample A-Auger C-Core G-Grab V-Vane S-Split Spoon O-Odex (air rotary) W-Wash (mud return) T-Shelby Tube CH Atterberg (Sa#10): PL:25% LL:58% Final Depth of Hole: 24.4 m Depth to Top of Rock: 17.5 m Page 1 of 3

29 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) 10 DRILLING DETAILS Reviewed by: 7 SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Rt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO 12 RECOVERY (%) 110 SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION CLAY, silty, varved, soft, high plasticity, grey, isolated gypsum crystals, MC>PL. (continued) Date(s) Drilled: Oct. 8, 2015 Driller: Jesse Rushton Drill Make/Model: Truck Mounted Drilling Method: Solid Stem Augers CLASSIFICATION Drill Hole #: DH15-2 Drilling Company: Peace Drilling COMMENTS TESTING Drillers Estimate {G % S % F %} ELEVATION (m) at 11.3m, dropstone SILT, and CLAY, trace sand, layered, soft, low to intermediate plasticity, grey, MC>PL, rapid dilatancy m ML- CL Atterberg (Sa#14): PL:23% LL:30% CLAY, silty, varved, layered with clayey silt, stiff, intermediate plasticity, grey, MC>PL m Atterberg (Sa#16): PL:19% LL:40% 662 CL MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample A-Auger C-Core G-Grab V-Vane S-Split Spoon 51 O-Odex (air rotary) W-Wash (mud return) T-Shelby Tube - below 16.8m, no silt layering. BEDROCK, siltstone, poorly lithified, extremely weak (R0), highly weathered, light grey m Final Depth of Hole: 24.4 m Depth to Top of Rock: 17.5 m Page 2 of 3

30 Prepared by: Geonorth Engineering Ltd Logged by: JAH DEPTH (m) 20 DRILLING DETAILS Reviewed by: SUMMARY LOG Project: La Guarde Creek Bridge Crossing Location: Siphon Creek Road, 40 km northeast of Fort St. John, B.C. Elevation: SHEAR STRENGTH (kpa) POCKET PEN Station/Offset: m Rt DYNAMIC CONE (BLOWS/300 mm) Natural Vane (KPa) Remold Vane (KPa) SPT "N" (BLOWS/300 mm) W P% W% W L% Northing/Easting: , m SAMPLE TYPE SAMPLE NO RECOVERY (%) SOIL SYMBOL Alignment: Existing Datum: 10V Coordinates taken with GPS SOIL DESCRIPTION BEDROCK, siltstone, poorly lithified, extremely weak (R0), highly weathered, light grey. (continued) Date(s) Drilled: Oct. 8, 2015 Driller: Jesse Rushton Drill Make/Model: Truck Mounted Drilling Method: Solid Stem Augers CLASSIFICATION Drill Hole #: DH15-2 Drilling Company: Peace Drilling COMMENTS TESTING Drillers Estimate {G % S % F %} ELEVATION (m) Refusal, 50 for 3" below 21.0m, isolated shale layers, very weak (R1), moderately weathered, dark grey. BR Refusal, 50 for 6" End of drill hole at 24.4m. No seepage encountered m MOT-SOIL-REV GINT-REV1B-MOT-DH LOGS.GPJ MOT-DRAFT-REV1A.GDT 16/01/ Legend Sample Type: L#-Lab Sample A-Auger C-Core G-Grab V-Vane S-Split Spoon O-Odex (air rotary) W-Wash (mud return) T-Shelby Tube Final Depth of Hole: 24.4 m Depth to Top of Rock: 17.5 m Page 3 of 3

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