Geotechnical Engineering Report

Transcription

1 Geotechnical Engineering Report O Reilly Auto Parts Store 1311 E. Nine Mile Road Highland Springs, Virginia August 8, 2012 Project No Prepared for: Oglesby Partners, Inc. Chattanooga, Tennessee Prepared by: Terracon Consultants, Inc. Raleigh, North Carolina

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3 TABLE OF CONTENTS Page EXECUTIVE SUMMARY... i 1.0 INTRODUCTION PROJECT INFORMATION Project Description Site Location and Description SUBSURFACE CONDITIONS Typical Profile Groundwater Site Geology RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION Geotechnical Considerations Earthwork Compaction Requirements Grading and Drainage Construction Considerations Foundation Recommendations Floor Slabs Seismic Considerations Pavements GENERAL COMMENTS...10 APPENDIX A FIELD EXPLORATION Exhibit A-1 Site Location Plan Exhibit A-2 Boring Location Plan Exhibit A-3 Field Exploration Description B-1 through B-6 Boring Logs APPENDIX B SUPPORTING DOCUMENTS Exhibit B-1 General Notes Exhibit B-2 Unified Soil Classification

4 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No EXECUTIVE SUMMARY A geotechnical engineering report has been completed for the proposed new O Reilly Auto Parts retail store to be located at 1311 E. Nine Mile Road in Highland Springs, Virginia. Six borings were performed to depths of approximately 15 feet below the existing site grades. The following geotechnical considerations were identified: In our opinion, the soils encountered in the borings are generally suitable for support of the proposed foundations, slabs, and pavements when tested and prepared as outlined in this report. The surface soils in portions of the site were soft at the time of the exploration and will potentially require additional remedial work during site preparation. Fill material was encountered in Boring Nos. B-5 to a depth of three feet below the existing surface. The fill material encountered generally consisted sandy clay and was found to be relatively stiff and free of debris. Even with the recommended site improvement and construction testing services there is an inherent risk for the owner that compressible fill or unsuitable material within or buried by the fill will not be discovered. This risk of unforeseen conditions cannot be eliminated without completely removing the existing fill. These risks can be reduced by performing adequate testing and evaluation during construction. The on-site soils are moisture sensitive and will become soft and unstable when wet. Due to the potential for unstable subgrades during wet weather, performing earthwork operations during warmer, drier periods of the year is preferable. Performing site preparation and earthwork at other times of the year increases the potential for having to perform remedial work on the subgrade soils. With redevelopment sites, there is always the potential that buried structures not discovered during the geotechnical exploration may exist at the site. These structures, such as septic tanks, grease traps, or other vaults, if encountered, can be addressed during construction. The geotechnical engineer should be retained during the construction phase of the project to observe earthwork and to perform necessary tests and observations during subgrade preparation; proof-rolling; placement and compaction of fill soils; backfilling of excavations into the completed subgrade, and just prior to construction of foundations. This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the Responsive Resourceful Reliable i

5 1.0 INTRODUCTION GEOTECHNICAL ENGINEERING REPORT O REILLY AUTO PARTS STORE 1311 E. NINE MILE ROAD HIGHLAND SPRINGS, VIRGINIA Project No August 8, 2012 A geotechnical engineering report has been completed for the proposed new O Reilly Auto Parts retail store to be located at 1311 E. Nine Mile Road in Highland Springs, Virginia. Six borings were performed to depths of approximately 15 feet below the existing ground surface at the approximate locations indicated on the boring location plan included in Appendix A of this report. The purpose of these services is to provide information and geotechnical engineering recommendations relative to: subsurface soil conditions foundation design and construction groundwater conditions seismic considerations earthwork floor slab design and construction pavements 2.0 PROJECT INFORMATION 2.1 Project Description Item Building construction Finished floor elevation Maximum loads, assumed Grading Description Approximate 7,200-square foot building with surrounding paved parking and drive lanes. The structure will be steel frame construction supported on a reinforced concrete foundation system consisting of column and wall footings and slab-on-grade floors. Expected to be within two feet of current site elevations. Building: Column Load 100 to 125 kips Continuous Load-Bearing Wall Loads less than 3 klf Maximum Uniform Floor Slab Load less than 100 psf Assumed to be less than 2 to 3 feet of excavation or fill placement. Responsive Resourceful Reliable 1

6 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled GENERAL COMMENTS should be read for an understanding of the report limitations. Responsive Resourceful Reliable ii

7 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Site Location and Description Item Location Existing improvements Current ground cover Existing topography Description Site address is 1311 East Nine Mile Rd. Highland Springs, Virginia. For further details regarding site location, refer to Exhibit A-1, Site Location Plan. An existing single family residence is at the site with a stone base driveway. A brick wall approximately 3 to 6 feet high is located along the west portion of the site. Grass Covered and Partially Wooded The site is relatively flat to gently sloping. 3.0 SUBSURFACE CONDITIONS 3.1 Typical Profile Based on the results of the borings, subsurface conditions on the project site can be generalized as follows: Description Approximate Depth to Bottom of Stratum Material Encountered Consistency/Density Surface 2 to 4 inches Topsoil and Stone Base Course N/A Stratum 1A 3 feet Fill, consisting of Sandy Clay and Native Sandy Clay Stiff Stratum 1B 3 feet Sandy Clay / Clay Soft to Stiff Stratum 2 To boring termination depth of 10 to 15 feet Sandy Clay and Clayey Sand Very Stiff to Hard (Clay) and Medium Dense (Sand) Further details of the conditions encountered in the borings can be found on the boring logs in Appendix A of this report. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. 3.2 Groundwater The boreholes were observed after the completion of drilling for the presence and level of groundwater. Groundwater was not encountered in the open boreholes, however, groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the borings were performed. The possibility of groundwater level Responsive Resourceful Reliable 2

8 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No fluctuations should be considered when developing the design and construction plans for the project. 3.3 Site Geology The subject site is located in the Coastal Plain Physiographic Province. The Coastal Plain soils consist mainly of marine sediments that were deposited during successive periods of fluctuating sea level and moving shoreline. The soils include sands, silts, and clays with irregular deposits of shells, which are typical of those lain down in a shallow sloping sea bottom. Recent alluvial sands, silts, and clays are typically present near rivers and creeks. According to the 1993 Geologic Map of Virginia, the site is mapped within the Pliocene Sand and Gravel Deposit. 4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION 4.1 Geotechnical Considerations In our opinion, the soils encountered in the borings are generally suitable for support of the proposed foundations, slabs, and pavements when tested and prepared as outlined in this report. Fill material was encountered in Boring Nos. B-5 to a depth of three feet below the existing surface. The fill material encountered generally consisted sandy clay and was found to be relatively stiff and free of debris. Even with the recommended site improvement and construction testing services there is an inherent risk for the owner that compressible fill or unsuitable material within or buried by the fill will not be discovered. This risk of unforeseen conditions cannot be eliminated without completely removing the existing fill. These risks can be reduced by performing adequate testing and evaluation during construction. We recommend that the site be proofrolled under the direction of the geotechnical engineer. If excessive deflection or rutting is observed, the geotechnical engineer should be contacted for stabilization options. We expect that localized areas will require remedial work. The soft soils encountered to a depth of three feet in the vicinity of Boring Nos. B-1 and B-3 are expected to require over-excavation and replacement if they are not removed as part of the site grading plan. The foundation bearing materials should be evaluated at the time of the foundation excavation. A representative of the geotechnical engineer should use a combination of hand auger borings and dynamic cone penetrometer (DCP) testing to determine the suitability of the bearing materials for the design bearing pressure. This testing should be extended to a depth of at least three feet below the design footing subgrade elevation. Excessively soft, loose or wet bearing soils should be over-excavated to a depth recommended by the geotechnical engineer. We expect that the on-site soil is generally suitable for re-compaction in overexcavated areas. Responsive Resourceful Reliable 3

9 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No The on-site soils are moisture sensitive and will become soft and unstable when wet. Due to the potential for unstable subgrades during wet weather, performing earthwork operations during warmer, drier periods of the year is preferable. Performing site preparation and earthwork at other times of the year increases the potential for having to perform remedial work on the subgrade soils. With redevelopment sites, there is always the potential that buried structures not discovered during the geotechnical exploration may exist at the site. These structures, such as septic tanks, grease traps, or other vaults, if encountered, can be addressed during construction. The geotechnical engineer should be retained during the construction phase of the project to observe earthwork and to perform necessary tests and observations during subgrade preparation; proof-rolling; placement and compaction of fill soils; backfilling of excavations into the completed subgrade, and just prior to construction of foundations. A more complete discussion of these points and additional information is included in the following sections. 4.2 Earthwork Site preparation should begin with complete demolition and removal of existing structures from construction areas. Utilities that are to be abandoned should be removed and the resulting excavations properly backfilled. Grass and topsoil should be stripped from construction areas. Based on the borings, we anticipate approximately 2 to 4 inches of topsoil, however, topsoil stripping depths may vary and should be evaluated at the time of construction by a representative of the geotechnical engineer. We expect deeper stripping depths in the vicinity of some of the more mature trees in the area. After site stripping, the exposed subgrade soils should be proofrolled to detect soft or loose soils. Proofrolling should be performed with a loaded, tandem-axle dump truck (gross weight of 20,000 lb) or similar rubber-tired construction equipment. The proofrolling operations should be observed by a representative of the geotechnical engineer. If excessive deflection or rutting is observed, the geotechnical engineer should be contacted for remedial work / stabilization options. The soft sandy clay encountered to a depth of three feet in Boring Nos. B-1 and B-3 is an example of an area where remedial work should be expected, although dry soil conditions at the time of the site preparation may improve the suitability of these materials for subgrade support. Remedial work options can potentially include localized over-excavation and replacement with properly compacted soil fill or the use of geotechnical fabric and crushed stone base materials. Responsive Resourceful Reliable 4

10 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No New engineered fill soil should meet the following requirements. Fill Type 1 USCS Classification Acceptable Location for Placement Low Plasticity Soil On-site soils SM, SC or SP with (LL < 60 & PI < 30) SC and All locations and elevations The on-site soils generally appear suitable for use as fill Controlled, compacted fill should consist of approved materials that are free of organic matter and debris. A sample of each material type should be submitted to the geotechnical engineer for evaluation Compaction Requirements Fill Lift Thickness Item Compaction Requirements 1 Moisture Content Cohesive Soil Description 9-inches or less in loose thickness (4 to 6 lifts when handoperated equipment is used) 95% of the materials standard Proctor maximum dry density (ASTM D698) Within the range of -3% to +3% of optimum moisture content as determined by the standard Proctor test at the time of placement and compaction 1. Engineered fill should be tested for moisture content and compaction during placement. If in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the tests should be reworked and retested as required until the specified moisture and compaction requirements are achieved Grading and Drainage During construction, grades should be sloped to promote runoff away from the construction area. Final surrounding grades should be sloped away from the structure on all sides to prevent ponding of water. Gutter / downspout discharge into landscaped areas adjacent to the building should be avoided. This can be accomplished through the use of splash-blocks, downspout extensions, and flexible pipes that are designed to attach to the end of the downspout. Flexible pipe should only be used if it is daylighted in such a manner that it gravity-drains collected water. Splash-blocks should also be considered below hose bibs and water spigots. Responsive Resourceful Reliable 5

11 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Construction Considerations The site should be graded to prevent ponding of surface water on the prepared subgrades or in excavations. If the subgrade should become frozen, desiccated, saturated, or disturbed, the affected material should be removed or these materials should be scarified, moisture conditioned, and recompacted. As a minimum, all temporary and permanent excavations should comply with applicable local, state and federal safety regulations, including the current OSHA Excavation and Trench Safety Standards. The geotechnical engineer should be retained during the construction phase of the project to observe earthwork and to perform necessary tests and observations during subgrade preparation; proof-rolling; placement and compaction of controlled compacted fills; backfilling of excavations to the completed subgrade, and prior to placing reinforcing steel in the footing excavations. 4.3 Foundation Recommendations Design recommendations for a shallow foundation system are presented in the following table and paragraphs. Description Net allowable bearing pressure 1 Minimum embedment below lowest adjacent finished grade for frost protection and protective embedment 2 Minimum width for continuous wall footings Minimum width for isolated column footings Approximate total settlement 3 Estimated differential settlement 3 Coefficient of friction, base of footing (for lateral resistance) Value 2,500 psf 18 inches 16 inches 24 inches Up to 1 inch Less than 3/4 inch between over 40 feet The recommended net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the footing base elevation. 2. For perimeter footings and footings beneath unheated areas. 3. The actual magnitude of settlement that will occur beneath the foundations would depend greatly upon the condition of the existing fill to remain in place, the site earthwork phase, careful evaluation of foundation bearing conditions at the time of construction and the structural loading conditions. The estimated total and differential settlements listed assume that the foundation related earthwork and the foundation design are completed in accordance with our recommendations. Responsive Resourceful Reliable 6

12 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No The foundation bearing materials should be evaluated at the time of the foundation excavation. A representative of the geotechnical engineer should use a combination of hand auger borings and dynamic cone penetrometer (DCP) testing to determine the suitability of the bearing materials for the design bearing pressure. This testing should be extended to a depth of at least three feet below the design footing subgrade elevation. Excessively soft, loose or wet bearing soils should be over-excavated to a depth recommended by the geotechnical engineer. We expect that the on-site soil is generally suitable for re-compaction in overexcavated areas. Alternatively, the overexcavated materials could be removed and replaced with washed, crushed stone (VDOT No. 57) or other suitable engineered fill. The base of all foundation excavations should be free of water and loose soil prior to placing concrete. Concrete should be placed as soon as practical after excavating to reduce bearing soil disturbance. Should the soils at bearing level become excessively disturbed or saturated, the affected soil should be removed prior to placing concrete. We recommend that the geotechnical engineer be retained to observe and test the soil foundation bearing materials. 4.4 Floor Slabs Recommendations for floor slab support are presented in the following table and paragraphs. Item Floor slab support Modulus of subgrade reaction Aggregate base course/capillary break Description Newly placed engineered fill meeting the specifications outlined in this report 100 pounds per square inch per inch (psi/in 3 ) for point loading conditions 4 to 6 inches of free draining granular material (VDOT No. 57 or 67) Saw-cut control joints should be placed in the slab to help control the location and extent of cracking. For additional recommendations refer to the ACI Design Manual. Joints or any cracks that develop should be sealed with a water-proof, non-extruding compressible compound specifically recommended for heavy duty concrete pavement and wet environments. The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings. The slab designer should refer to ACI 302 and/or ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder. Responsive Resourceful Reliable 7

13 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Seismic Considerations Item Seismic Parameters International Building Code (IBC) D 2 Mapped Acceleration parameters, S S and S 1 S S = 0.20 and S 1 = The International Building Code (IBC) site seismic classification is based on a site soil profile determination extending a depth of 100 feet. The scope of work authorized did not include a boring to a depth of 100 feet. The recommended seismic site classification is based on the assumption that the soil encountered at the planned boring termination depth remains stiff density through a depth of 100 feet. This is a reasonable assumption based on the geology of the area. A geophysical exploration to develop the shear wave velocity profile to a depth of 100 feet could be utilized to verify the seismic site class or as an attempt to justify a higher seismic site class. The on-site soils are not expected to be subject to liquefaction under the magnitude of seismic events predicted for the area. 4.6 Pavements The existing soils encountered in the borings appear to be suitable for support of the planned pavement sections when tested and prepared as recommended in this report. Our recommendations for pavement design, construction, and maintenance are summarized in the following paragraphs and table. Pavement thickness design is dependent upon: the anticipated traffic conditions during the life of the pavement; subgrade and paving material characteristics; climatic conditions of the region. Two pavement section alternatives have been provided. The light-duty pavement sections are for car parking areas only. Heavy-duty pavement sections should be used for concentrated car traffic (drive lanes / entrance drives) and truck traffic areas. Climatic conditions are considered in the estimated design subgrade support value listed above and in the paving material characteristics. Recommended paving material characteristics are based on the Virginia Department of Transportation (VDOT) Road and Bridge Specifications. Responsive Resourceful Reliable 8

14 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Recommended pavement sections are listed in the table below. Pavement Type Rigid Flexible (Superpave) Material Portland Cement Concrete (4,000 psi) Crushed Stone (VDOT Size 21A) Layer Thickness (inches) Light Duty Heavy Duty Asphalt Surface (VDOT SM 9.0A) Asphalt Intermediate (VDOT IM 19.0B) Crushed Stone (VDOT Size 21A) Place in two lifts For areas subject to concentrated and repetitive loading conditions, i.e. dumpster pads and ingress/egress aprons, or in areas where vehicles will turn at low speeds, we recommend using a Portland cement concrete pavement with a thickness of at least 7 inches underlain by at least 4 inches of crushed stone. For dumpster pads, the concrete pavement area should be large enough to support the container and tipping axle of the refuse truck. The placement of a partial pavement thickness for use during construction is not suggested without a detailed pavement analysis incorporating construction traffic. In addition, we should be contacted to confirm the traffic assumptions outlined above. If the actual traffic varies from the assumptions outlined above, modification of the pavement section thickness will be required. Recommendations for pavement construction presented depend upon compliance with recommended material specifications. To assess compliance, observation and testing should be performed under the direction of the geotechnical engineer. Asphalt concrete aggregates and base course materials should conform to the applicable Virginia Department of Transportation (VDOT) "Road and Bridge Specifications. Concrete pavement should be air-entrained and have a minimum compressive strength of 4,000 psi after 28 days of laboratory curing (ASTM C-31). Responsive Resourceful Reliable 9

15 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Future performance of pavements constructed on the soils at this site will be dependent upon several factors, including: maintaining stable moisture content of the subgrade soils; providing for a planned program of preventative maintenance. The performance of all pavements can be enhanced by minimizing excess moisture which can reach the subgrade soils. The following recommendations should be considered a minimum: site grading at a minimum 2 percent grade away from the pavements; the subgrade and the pavement surface have a minimum 1/4 inch per foot slope to promote proper surface drainage; install joint sealant and seal cracks immediately; Prevention of infiltration of water into the subgrade is essential for the successful performance of any pavement. Both the subgrade and the pavement surface should be sloped to promote surface drainage away from the pavement structure. 5.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur across the site, or due to the modifying effects of weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the Responsive Resourceful Reliable 10

16 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. Responsive Resourceful Reliable 11

17 APPENDIX A FIELD EXPLORATION

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20 Geotechnical Engineering Report O Reilly Auto Parts Store Highland Springs, Virginia August 8, 2012 Terracon Project No Field Exploration Description The boring locations were located by measuring from existing site features and ground surface elevations were not obtained. The locations and elevations of the borings should be considered accurate only to the degree implied by the means and methods used to define them. The borings were drilled with a truck mounted CME-75 rotary drill rig using hollow stem auger techniques to advance the boreholes. Samples of the soil encountered in the borings were obtained using the split barrel sampling procedures. In the split-barrel sampling procedure, the number of blows required to advance a standard 2-inch O.D. split-barrel sampler the last 12 inches of the typical total 18-inch penetration by means of a 140-pound hammer with a free fall of 30 inches, is the standard penetration resistance value (SPT-N). This value is used to estimate the in-situ relative density of cohesionless soils and consistency of cohesive soils. An automatic SPT hammer was used to advance the split-barrel sampler in the borings performed on this site. A greater efficiency is typically achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. Published correlations between the SPT values and soil properties are based on the lower efficiency cathead and rope method. This higher efficiency affects the standard penetration resistance blow count (N) value by increasing the penetration per hammer blow over what would be obtained using the cathead and rope method. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report. The samples were tagged for identification, sealed to reduce moisture loss, and taken to our laboratory for further examination, testing, and classification. Information provided on the boring logs attached to this report includes soil descriptions, consistency evaluations, boring depths, sampling intervals, and groundwater conditions in accordance with the attached General Notes. The borings were backfilled with auger cuttings prior to the drill crew leaving the site. A field log of each boring was prepared by the drill crew. These logs included visual classifications of the materials encountered during drilling as well as the driller s interpretation of the subsurface conditions between samples. Final boring logs included with this report represent the engineer's interpretation of the field logs and estimated Unified Soil Classification Symbols based on visual manual procedures. A brief description of this classification system is attached to this report.

21 IENT SITE LOG OF BORING NO. B-1 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) 0.3 Approx. 4" STONE BASE SANDY AY tan-brown, soft to very stiff AYEY SAND tan-brown, medium dense 10 SC SANDY AY gray and orange, very stiff BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 7.0 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

22 IENT SITE LOG OF BORING NO. B-2 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) 0.2 Approx. 2" TOPSOIL SANDY AY tan-brown, medium stiff to very stiff AYEY SAND gray and orange, with rounded gravel, medium dense SANDY AY gray and orange, very stiff 5 10 SC BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 6.4 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

23 IENT SITE LOG OF BORING NO. B-3 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) 0.3 Approx. 3" TOPSOIL SANDY AY to AY tan-brown to gray, red, and orange, soft to very stiff -with rounded gravel from 3 to 8 feet BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 6.2 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

24 IENT SITE LOG OF BORING NO. B-4 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) 0.2 Approx. 2" STONE BASE SANDY AY to AY tan-brown to gray, red, and orange, stiff to hard -with rounded gravel from 3 to 8 feet BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 6.2 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

25 IENT SITE LOG OF BORING NO. B-5 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) Approx. 3" TOPSOIL FILL, consisting of SANDY AY tan-brown SANDY AY to AY gray, red, and orange, very stiff to hard -with rounded gravel from 3 to 8 feet BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 6.0 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

26 IENT SITE LOG OF BORING NO. B-6 Oglesby Partners, Inc. PROJECT Highland Springs, Virginia O'Reilly Auto Parts Store SAMPLES TESTS Page 1 of 1 GRAPHIC LOG DESCRIPTION DEPTH, ft. USCS SYMBOL NUMBER TYPE RECOVERY, in. SPT - N BLOWS / ft. WATER CONTENT, % DRY UNIT WT pcf Unconfined Compressive Strength (tsf) 0.3 Approx. 3" TOPSOIL SANDY AY to AY tan-brown to gray, red, and orange, stiff to hard -with rounded gravel from 5 to 8 feet BORING TERMINATED BOREHOLE_99 LOGS_ GPJ GAGE TERRACON.GDT 8/6/12 The stratification lines represent the approximate boundary lines between soil and rock types: in-situ, the transition may be gradual. WATER LEVEL OBSERVATIONS, ft N/E AB 5.1 feet BORING STARTED BORING COMPLETED RIG CME-75 FOREMAN JRT APPROVED BCH JOB #

27 APPENDIX B SUPPORTING DOCUMENTS

28 GENERAL NOTES DRILLING & SAMPLING SYMBOLS: : Split Spoon 1-3 / 8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube - 2" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler " I.D., 3" O.D., unless otherwise noted HA: Hand Auger DB: Diamond Bit Coring - 4", N, B RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary The number of blows required to advance a standard 2-inch O.D. split-spoon sampler () the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the Standard Penetration or N-value. WATER LEVEL MEASUREMENT SYMBOLS: : Water Level WS: While Sampling N/E: Not Encountered WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations. DESCRIPTIVE SOIL AIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. Unconfined Compressive Strength, Qu, psf CONSISTENCY OF FINE-GRAINED SOILS Standard Penetration or N-value () Blows/Ft. Consistency RELATIVE DENSITY OF COARSE-GRAINED SOILS Standard Penetration or N-value () Blows/Ft. Ring Sampler (RS) Blows/Ft. Relative Density < 500 <2 Very Soft Very Loose 500 1, Soft Loose 1,001 2, Medium Stiff Medium Dense 2,001 4, Stiff Dense 4,001 8, Very Stiff Very Dense 8, Hard RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term(s) of other Percent of Major Component Constituents Dry Weight of Sample Particle Size Trace < 15 Boulders Over 12 in. (300mm) With Cobbles 12 in. to 3 in. (300mm to 75 mm) Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm) Sand Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm) Passing #200 Sieve (0.075mm) RELATIVE PROPORTIONS OF FINES PLASTICITY DESCRIPTION Descriptive Term(s) of other Percent of Plasticity Term Constituents Dry Weight Index Trace < 5 Non-plastic 0 With 5 12 Low 1-10 Modifiers > 12 Medium High 30+ Exhibit B-1

29 UNIFIED SOIL AIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Coarse Grained Soils: More than 50% retained on No. 200 sieve Fine-Grained Soils: 50% or more passes the No. 200 sieve Gravels: More than 50% of coarse fraction retained on No. 4 sieve Sands: 50% or more of coarse fraction passes No. 4 sieve Silts and Clays: Liquid limit less than 50 Silts and Clays: Liquid limit 50 or more Group Symbol Soil Classification Group Name B Clean Gravels: Cu 4 and 1 Cc 3 E GW Well-graded gravel F Less than 5% fines C Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F Gravels with Fines: Fines classify as ML or MH GM Silty gravel F,G, H More than 12% fines C Fines classify as or CH GC Clayey gravel F,G,H Clean Sands: Cu 6 and 1 Cc 3 E SW Well-graded sand I Less than 5% fines D Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I Sands with Fines: Fines classify as ML or MH SM Silty sand G,H,I More than 12% fines D Fines Classify as or CH SC Clayey sand G,H,I Inorganic: Organic: Inorganic: Organic: PI 7 and plots on or above A line J Lean clay K,L,M PI 4 or plots below A line J ML Silt K,L,M Liquid limit - oven dried Organic clay K,L,M,N 0.75 OL Liquid limit - not dried Organic silt K,L,M,O PI plots on or above A line CH Fat clay K,L,M PI plots below A line MH Elastic Silt K,L,M Liquid limit - oven dried Liquid limit - not dried Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat 0.75 OH Organic clay K,L,M,P Organic silt K,L,M,Q A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add with cobbles or boulders, or both to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay E Cu = D 60/D 10 Cc = D (D ) 2 x D 60 F If soil contains 15% sand, add with sand to group name. G If fines classify as -ML, use dual symbol GC-GM, or SC-SM. H If fines are organic, add with organic fines to group name. I If soil contains 15% gravel, add with gravel to group name. J If Atterberg limits plot in shaded area, soil is a -ML, silty clay. K If soil contains 15 to 29% plus No. 200, add with sand or with gravel, whichever is predominant. L If soil contains 30% plus No. 200 predominantly sand, add sandy to group name. M If soil contains 30% plus No. 200, predominantly gravel, add gravelly to group name. N PI 4 and plots on or above A line. O PI 4 or plots below A line. P PI plots on or above A line. Q PI plots below A line. Exhibit B-2