preliminary geotechnical engineering report proposed 78

Preliminary Geotechnical Engineering Report Proposed 78-Acre Development

Lazy Hawk Road Rock Hill, South Carolina

S&ME Project No. 1351-10-010

Prepared For:

Tom Cat Too, LLC 130 East Broad Street, Suite 102

Spartanburg, South Carolina 29306

Prepared By:

S&ME, Inc.

9751 Southern Pine Boulevard Charlotte, North Carolina 28273

March 17, 2010

TABLE OF CONTENTS

1.0 INTRODUCTION.................................................................................................................1 1.1 OVERALL PROJECT AND SITE DESCRIPTION .......................................................................1 1.2 PURPOSE AND SCOPE .......................................................................................................1

2.0 EXPLORATION PROCEDURES........................................................................................2 2.1 FIELD TESTING..................................................................................................................2 2.2 LABORATORY TESTING ......................................................................................................2

3.0 AREA GEOLOGY AND SUBSURFACE CONDITIONS....................................................3 3.1 PHYSIOGRAPHY AND AREA GEOLOGY ................................................................................3 3.2 SOIL SURVEY....................................................................................................................4 3.3 SUBSURFACE CONDITIONS ................................................................................................5 3.4 WATER LEVEL MEASUREMENTS.........................................................................................5

4.0 SITE DEVELOPMENT CONSIDERATIONS......................................................................6 4.1 EXPANSIVE MOISTURE-SENSITIVE SOILS............................................................................6 4.2 GROUNDWATER ................................................................................................................7 4.3 LIGHT-WEIGHT FILL...........................................................................................................7 4.4 EXISTING FILL ...................................................................................................................7

5.0 PRELIMINARY GEOTECHNICAL RECOMMENDATIONS...............................................7 5.1 GENERAL..........................................................................................................................7 5.2 EARTHWORK.....................................................................................................................7

5.2.1 Site Preparation..........................................................................................................7 5.2.2 Dewatering .................................................................................................................8 5.2.3 Excavations ................................................................................................................8 5.2.4 Fill Material and Placement ........................................................................................9

5.3 SEISMIC DESIGN .............................................................................................................10 5.4 FOUNDATIONS ................................................................................................................10 5.5 FLOOR SLABS .................................................................................................................11 5.6 RETAINING WALLS ..........................................................................................................11 5.7 PAVEMENTS....................................................................................................................12 5.8 FINAL GEOTECHNICAL EXPLORATION ...............................................................................13

6.0 LIMITATIONS OF REPORT .............................................................................................13 APPENDIX Site Vicinity Map, Figure 1 Boring Location Plan, Figure 2 Legend to Soil Classification and Symbols Boring Logs, B-1 through B-12

Preliminary Geotechnical Engineering Report S&ME Project No. 1351-10-010 Proposed 78-Acre Development Rock Hill, South Carolina March 17, 2010

1.0 INTRODUCTION

1.1 Overall Project and Site Description Project information is based on a telephone conversation between Tom Arthur and Brian McKean of S&ME on January 18, 2010. We understand that plans are to market an approximately 78-acre site (York County Parcel ID No. 617-00-00-001) located off of Lazy Hawk Road in Rock Hill, South Carolina as shown on the attached Site Vicinity Map (Figure 1) in the Appendix for possible sale or development. No specific plans have been developed, but we understand that some information is desired to indicate the suitability of the site for future development. The site is located to the west of the existing Blanchard Machinery Company building. Based on information obtained from the York County GIS website and our site reconnaissance, the site is mostly open with some areas to the south and west being tree covered. It appears based on available aerial maps that the land has been possibly used as a borrow source for structural fill material at one point. Two detention basins are noted on a survey plat provided by Mr. Arthur and completed by Keck & Wood surveyors. No other information has been provided to us at this time. Based on topographical information from the York County GIS website, elevations range from approximately 630 feet-MSL in the approximate center of the site to 580 feet-MSL in the southeastern corner of the site. The site generally slopes down from the center of the site in all directions.

1.2 Purpose and Scope The purpose of this limited geotechnical study was to determine the general subsurface conditions at the subject site and develop preliminary geotechnical conclusions and recommendations for future development of the site.

S&ME, Inc. has completed the following scope of geotechnical services for this project: • Visited the site to observe site surface conditions and marked proposed boring

locations; • Contacted Palmetto Utility Protection Services (PUPS) to mark the locations of

existing underground utilities in the proposed exploration areas; • Mobilized an ATV-mounted power drilling rig and crew to the site; • Drilled twelve (12) soil test borings to depths of 20 feet below existing grades; • Measured stabilized groundwater levels, backfilled the boreholes with soil cuttings

and installed a hole closure device near the ground surface in each borehole; • Prepared this preliminary geotechnical engineering report.

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2.0 EXPLORATION PROCEDURES

2.1 Field Testing In order to explore the general subsurface conditions at the project site, twelve soil test borings (B-1 through B-12) were performed at the site to depths of 20 feet below existing grades. The soil test borings were advanced at the approximate locations shown on the attached Boring Location Plan (Figure No. 2) in the Appendix. The locations of the borings were selected by S&ME and located in field by a geotechnical staff professional from our office using a non-differential hand-held GPS device. A CME-550X drill rig mounted on an ATV carrier was used to advance the borings with hollow-stem, continuous flight augers. Standard Penetration Test (SPT) split spoon sampling was performed at designated intervals in the soil test borings in general accordance with ASTM D 1586 to provide an index for estimating soil strength and relative density or consistency and to retrieve samples for soil classification purposes. Representative portions of each soil sample were placed in glass jars and taken to our laboratory. The CME-550X drill rig used to drill the borings is equipped with a hydraulic automatic hammer for Standard Penetrations tests rather than the traditional rope, cathead and safety hammer. The N-values reported on the attached Boring Logs are the actual field measured blow counts and are not corrected for the hammer energy. Water level measurements were attempted at the termination of drilling activities in all borings. All boreholes were backfilled with soil cuttings on March 1, 2010.

2.2 Laboratory Testing Once the soil test boring samples were received in our office, a geotechnical staff professional observed each sample to estimate the distribution of grain size, plasticity, organic content, moisture condition, color, presence of lenses and seams and apparent geological origin. The soils were visually classified in general accordance with the Unified Soil Classification System (USCS). The results of the classifications, as well as the field test results, are presented on the individual boring logs included in the Appendix. Similar soils were grouped into strata on the logs. The strata contact lines represent approximate boundaries between the soil types; the actual transition between the soil types in the field may be gradual in both the horizontal and vertical directions.

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3.0 AREA GEOLOGY AND SUBSURFACE CONDITIONS

3.1 Physiography and Area Geology The site is located in the Charlotte Belt of the Piedmont Physiographic Province of South Carolina as shown in the following figure. The Piedmont Province generally consists of well-rounded hills and ridges, which are dissected by a well-developed system of draws and streams. The Piedmont Province is predominantly underlain by metamorphic rock (formed by heat, pressure and/or chemical action) and igneous rock (formed directly from molten material), which were initially formed during the Precambrian and Paleozoic eras. The volcanic and sedimentary rocks deposited in the Piedmont Province during the Precambrian eras were the host for the metamorphism and were changed to gneiss and schist. The more recent Paleozoic era had periods of igneous emplacement, with at least several episodes of regional metamorphism resulting in the majority of the rock types seen today.

APPROXIMATE SITE LOCATION

Physiographic Provinces of South Carolina

The topography and relief of the Piedmont Province have developed from differential weathering of the igneous and metamorphic rock. Because of the continued chemical and physical weathering, the rocks in the Piedmont Province are now generally covered with a mantle of soil that has weathered in place from the parent bedrock. These soils have variable thicknesses and are referred to as residuum or residual soils. The residuum is typically finer grained and has higher clay content near the surface because of the advanced weathering. Similarly, the soils typically become coarser grained with increasing depth because of decreased weathering. As the degree of weathering decreases, the residual soils generally retain the overall appearance, texture, gradation and foliations of the parent rock.

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The boundary between soil and rock in the Piedmont is not sharply defined. A transitional zone termed “Partially Weathered Rock” is normally found overlying the parent bedrock. Partially Weathered Rock (PWR) is defined for engineering purposes as residual material with Standard Penetration Resistances (N-values) exceeding 100 blows per foot. The transition between hard/dense residual soils and partially weathered rock occurs at irregular depths due to variations in degree of weathering. A graphic depiction of typical Piedmont weathering profiles is presented in the following figure.

Typical Piedmont Weathering Profiles (After Sowers/Richardson, 1983)

Groundwater is typically present in the residual soils and within fractures in the PWR or underlying bedrock in the Piedmont. On upland ridges in the Piedmont, groundwater may or may not be present in the residual soils above the PWR and bedrock. Alluvial soils, which have been transported and deposited by water, are typically found in floodplains and are generally saturated to within a few feet of the ground surface. Fluctuations in groundwater levels are typical in residual soils and partially weathered rock in the Piedmont, depending on variations in precipitation, evaporation, and surface water runoff. Seasonal high groundwater levels are expected to occur during or just after the typically wetter months of the year (November through April).

3.2 Soil Survey The Soil Survey Report for York County, South Carolina, (published by the United States Department of Agriculture Natural Resource Conservation Service in 2007) indicates that there are three main soil series on the subject site. The majority of the project site is underlain by soils classified as Cecil clay loam (CcB3, CcC3 and CcD3), Cecil sandy loam (CdB2) and Lloyd loam (LdB2) Soil Series. The following soil properties are given in the Soil Survey Report for York County:

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Soil Name

Typical Depth

(inches)

Unified Classification

LiquidLimit

PlasticityIndex

Flood Freq.

High Water Table

(ft)

Depth to Bedrock

(ft)

Cecil clayey loam

0 - 5 5 - 32 32 - 79

ML, SM ML SM

20 - 31 31 - 49 13 - 21

2 - 7 7 - 15 NP - 3

None >6 >6

Cecil sandy loam

0 - 5 5 - 32 32 - 79

ML, SM ML SM

20 - 31 31 - 49 13 - 21

NP - 2 7 - 15 NP - 3

None >6 >6

Lloyd loam

0 - 6 6 - 47 47 - 79

SC-SM, SM ML SM

9 - 20 31 - 49 13 - 21

2 - 7 7 - 15 NP - 3

None >6 >6

3.3 Subsurface Conditions Subsurface conditions as indicated by the soil test borings generally consist of surficial materials consisting of topsoil underlain by fill or residual soil to the boring termination depths. The generalized subsurface conditions at the site are described below. For more detailed soil descriptions and stratifications at a particular boring location, the respective boring log should be reviewed. Surface Materials: Borings B-2, B-3 and B-7 encountered topsoil. The surficial topsoil thickness in the borings was measured at approximately 2 to 3 inches. Fill Soils: Beneath the surficial materials, fill soils were encountered in Borings B-2, B-3 and B-10 to depths of 3 to 5.5 feet below the existing ground surface. The fill soils generally consisted of stiff silty clay (CH), stiff sandy clay (CL) and firm sandy silt (ML). N-values ranged from 7 to 13 blows per foot (bpf) in the fill soils. Residual Soils: Beneath the surficial materials or fill soils, residual soils were encountered in all of the borings. The residual soils generally consisted of stiff to very stiff silty clay (CH), stiff to hard clayey silt (MH), stiff sandy clay (CL), firm to very stiff sandy silt (ML) and loose silty sand (SM). The majority of the residual soils were micaceous. N-values ranged from 7 to 32 bpf in the residual soils. All borings were terminated in residual soils.

3.4 Water Level Measurements Water was observed in Boring B-5 at a depth of 18 feet below the existing ground surface when water level measurements were attempted at boring termination. All other borings were dry at the termination of drilling activities. All boreholes were left open for a stabilization period of at least 24 hours and water levels were checked before being backfilled. Borings B-2, B-5 and B-10 encountered water levels at depths of 14, 13.3 and 14.2 feet, respectively. All other borings were dry. The boreholes caved in following drilling at depths ranging from 14.6 to 16.2 feet below the existing ground surface. The

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borehole cave-in depths for the soil test borings, which are also included on the individual logs, may be an indication of groundwater at or near the cave-in depth when the borings are extended below the groundwater level. All borings were backfilled on March 1, 2010. Groundwater levels tend to fluctuate with seasonal and climatic variations, as well as with some types of construction operations. Therefore, water may be encountered during construction operations at depths or elevations different than indicated in this study.

4.0 SITE DEVELOPMENT CONSIDERATIONS

The results of the testing program indicate that the subsurface conditions are generally consistent with conditions previously encountered in this area of York County and are generally favorable for support of the proposed pavements and lightly to moderately loaded structures on shallow foundations. The following conditions should be considered for preliminary budgeting and scheduling purposes.

4.1 Expansive Moisture-Sensitive Soils Based on our manual classification of the split-spoon samples, near-surface plastic soils (CH and MH) were encountered across the site. In addition, the USDA Soil Survey for York County also indicate the potential for near-surface plastic soils. These plastic soils can experience change in volume (shrink/swell) with changes in their moisture content that can potentially cause building/pavement distress. In addition, these soils are highly sensitive to moisture and can degrade quickly if allowed to saturate. As such, care should be taken to prevent these materials from directly underlying structures that are affected by soil movement. In general, undercutting of these materials to provide adequate separation from structural subgrades is required. For preliminary purposes, we recommend 3 feet of separation material consisting of low-plasticity soils be provided between plastic soils and structural subgrades (e.g., pavement, slab, and foundation subgrades). In some cases, residual moderately plastic clayey silts (MH) can remain in place if they are stable based on an evaluation during construction. In many parts of the country, project specifications commonly exclude CH and MH materials from use as structural fill due to potential volume change with changes in soil moisture content, low strength, and moisture sensitivity. Because these materials are the predominant near-surface soil type in the site area, they are commonly used in this area as fill. In some cases, the moderately plastic soils (MH) can be re-used if they are well-mixed with low-plasticity soils and both moderately and highly plastic soils (MH and CH) can be re-used without mixing in deeper fill areas where confining pressures will counteract swell pressures. The potential uses of these plastic materials in structural areas should be performed under the direction of the geotechnical engineer. It should be noted that because these soils are sensitive to moisture, significant moisture-conditioning may be required to achieve the project compaction criteria. Additional preparation of these materials (undercutting, moisture-conditioning, etc.) should be

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anticipated if construction occurs during the wetter months of the year and when working with soils excavated at or below the water table.

4.2 Groundwater As previously indicated, groundwater level measurements ranged from 13.3 to 18 feet below the existing ground surface. Preliminary proposed grades have not been given for the site. Therefore, depending on final grades, temporary and/or permanent dewatering may be required.

4.3 Light-Weight Fill Based on our experience, the on-site micaceous residual silts tend to have a low dry unit weight (less than 90 pcf) when placed as fill. They can be very difficult to compact and tend to result in relatively compressible, weak structural fills. The use of these soils should be limited in the building, pavement, or retaining wall/fill slope areas. Additional sampling and testing (laboratory standard Proctor compaction) to determine the suitability of cut area soils should be performed during the design phase geotechnical exploration for this project.

4.4 Existing Fill Existing fill soils were encountered in Borings B-2, B-3 and B-10, which were performed in what appears to be access roads for the site. Based on our site reconnaissance, we do not anticipate the presence of significant existing fill soils across the site. Where existing fill soils are present and development is planned, we recommend undercutting of the existing fill soils and replacement with properly compacted structural fill. The undercut should extend to stable residual soils. Existing low plasticity fill soils may be reused as structural fill provided they are clean and free of organics. However, additional characterization of these materials should be performed using larger trench or pit excavations during construction.

5.0 PRELIMINARY GEOTECHNICAL RECOMMENDATIONS

5.1 General The following preliminary conclusions and recommendations presented are based on the data obtained from the limited field testing program and are intended to provide a general assessment of geotechnical conditions at the site. Once plans progress for the site, a final design exploration should be performed to develop specific geotechnical design and construction recommendations.

5.2 Earthwork

5.2.1 Site Preparation The entire building and pavement areas should be stripped of all topsoil, trash, debris, and other organic materials to a minimum of 10 feet outside the structural and pavement limits. The borings indicate topsoil thickness ranging from just 2 to 3 inches. Our experience, however, suggests an average stripping depth of 12-inches is required for

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heavily wooded areas, such as the southern portion of the site. All debris from stripping operations should be properly disposed. Alternatively, topsoil may be used in landscaped areas with slopes of 4H:1V or less. Upon completion of the stripping operations, areas to provide support for the foundations, floor slab, structural fill and any pavement areas should be proofrolled with a loaded dump truck or similar pneumatic tired vehicle (minimum loaded weight of 20 tons) under the observation of a staff professional or a senior soil technician. After excavation of the site has been completed, the exposed subgrade in cut areas should also be proofrolled. The proofrolling procedures should consist of four complete passes of the exposed areas, with two of the passes being in a direction perpendicular to the preceding ones. Any areas which deflect, rut or pump excessively during proofrolling or fail to "tighten up" after successive passes should be undercut to suitable soils and replaced with compacted fill. After the proofrolling operation has been completed and approved, final site grading should proceed immediately. If construction progresses during wet weather, the proofrolling operation should be repeated with at least one pass in each direction immediately prior to placing aggregate base course in the parking areas. If unstable conditions are exposed during this operation, then undercutting or scarifying may be required.

5.2.2 Dewatering Based on the range of existing ground surface elevations, we anticipate temporary and/or permanent dewatering will not be required for a majority of the site. However, perched or entrapped water may be present within the upper firm to hard residual soils during the wet seasons; typically from November through March. Therefore; temporary dewatering could be necessary in conjunction with site preparation activities. Temporary dewatering can be accomplished with temporary excavations and sump pumps. Permanent dewatering can be accomplished by installing French drains. Other means of improving drainage at the site may be accomplished with ditches located at select areas.

5.2.3 Excavations Based on the borings performed, we anticipate the majority of excavations at the site will be in existing fill or firm to very stiff and loose to dense residual soils. We anticipate the residual soils, as well as any newly placed fill soils, can be excavated using traditional equipment such as backhoes, trackhoes, bulldozers, and front-end loaders. Although the soil test borings did not encounter PWR, the depth to, and thickness of, PWR and rock lenses or seams, can vary dramatically in short distances and between boring locations; therefore, PWR or bedrock may be encountered during construction at locations or depths, between boring locations, not encountered during this exploration. Our experience in this geological area indicates that the upper 2 to 3 feet of PWR can generally be excavated using pans and scrapers by first loosening with a single tooth ripper attached to a suitable sized dozer, such as a Caterpillar D-8 or D-9, or suitable

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sized trackhoe such as a Caterpillar C320 equipped with a rock bucket. A separate unit price should be established for excavation of these materials as they may not require blasting, but will take more time to excavate than soil. Jackhammering or blasting should be anticipated for excavation of PWR, rock, and boulders, if present, during open site excavation (i.e., excavations more than 10 feet wide and 30 feet long). In confined excavations (footings, utility trenches, etc.), these materials will probably require the use of blasting, pneumatic hammers, or hydraulic hammers to excavate. This should be anticipated for footing and utility excavations in these materials. Rock in a weathered, boulder, and massive form varies erratically in depth and location in the Piedmont Geologic Province. Therefore, there is always a potential that these materials could be encountered at shallower depths between the boring locations and may be encountered during general site grading and in trench excavations for the installation of footings and utilities. For temporary excavations, shoring and bracing or flattening (laying back) of the slopes should be performed to obtain a safe working environment. Excavations should be sloped or shored in accordance with local, state and federal regulations, including OSHA (29 CFR Part 1926) excavation trench safety standards. This information is provided only as a service and, under no circumstances, should we be assumed responsible for construction site safety. The contractor is usually solely responsible for site safety. Final project slopes should be designed at 3 horizontal to 1 vertical or flatter. Steeper slopes could be considered, particularly in cut areas, and can be evaluated once design grades are developed. The tops and bases of all slopes should be located a minimum of 10 feet from structural limits and a minimum of 5 feet from pavement limits. The fill slopes should be adequately compacted, as outlined below, and all slopes should be seeded and maintained after construction.

5.2.4 Fill Material and Placement All fill used at the subject site for grading operations should consist of a clean (free of organics and debris) soil with low-plasticity (Liquid Limit less than 50 and Plasticity Index less than 25). The proposed fill should have a maximum dry density of at least 90 pounds per cubic foot as determined by a Standard Proctor compaction test, ASTM D 698. All fill should be placed in loose lifts not exceeding 8 to 10 inches in thickness and compacted to a minimum of 95 percent of its Standard Proctor maximum dry density, with the final 18 inches below subgrade compacted to at least 98 percent. We recommend that field density tests, including one-point Proctor verification tests, be performed on the fill as it is being placed at a frequency determined by the geotechnical engineer. The near surface moderate to high plasticity clayey and silty soils (CH and MH) are typical of the area and, as discussed in Section 4.1 of this report, are moisture sensitive with low to moderate potential for volume change (MH) and some have moderate to high potential for volume change (CH). As discussed, the potential uses of these materials should be

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determined by the geotechnical engineer once site plans have been developed. For preliminary purposes, however, moderately plastic soils (MH) can be re-used if they are well-mixed with low-plasticity soils and both moderately and highly plastic soils (MH and CH) can be re-used without mixing in deeper fill areas (5 feet or more below structural subgrades). The clayey and silty soils (CH, CL, MH, and ML) that are the common near-surface soil types in this area are sensitive to moisture and may require significant drying to achieve the project compaction criteria. This is of particular importance if construction occurs during the wetter months of the year and when working with soils excavated at or below the water table. Fills more than 15 feet in height may need a delay period (typically of about 30 to 60 days) to settle prior to construction of pavements, utilities, buildings, etc, on the fills. Fill slopes should be no steeper than 3H:1V to ensure stable slopes. If steeper slopes are necessary, detailed slope stability analysis should be performed.

5.3 Seismic Design Future buildings constructed at the site should be designed to resist possible earthquake effects as determined in accordance with the current applicable South Carolina building code. Final site grades (i.e., amount of cut and fill) should be considered when evaluating site response under earthquake loading. Based on Section 1613 and Equation 16-42 of the 2006 International Building Code, and our experience with the typical subsurface conditions in the area, we estimate the average N-value to be greater than 15 and less than 50 bpf in the top 100 feet below the proposed foundation bearing elevations for a majority of the site. This implies a Seismic Site Class D can be used for preliminary design.

5.4 Foundations Based on the results of the soil test borings performed, subsurface conditions are generally favorable for lightly to moderately loaded buildings (column loads of 300 kips or less, wall loads less than 6 kips per foot) supported on conventional shallow foundations bearing on the low-plasticity residual soils, or newly placed structural fill. Net allowable bearing pressures of 3,000 pounds per square foot (psf) can be used for preliminary foundation design. If deeper (greater than 20 feet) cut depths are anticipated higher allowable bearing pressures may be available depending on final grades. Shallow foundations should be designed to bear at least 12 inches below finished grades for frost protection and protective embedment. Column footings should be at least 24 inches square and wall footings should be at least 18 inches wide to prevent a punching shear failure of the foundation bearing soils. All footing/mat excavations should be observed by the geotechnical engineer's representative to verify that suitable soils are present at and below the proposed bearing elevation. If soft to firm or other unsuitable materials are encountered in the footing excavations, they should be undercut and replaced to the bottom of footing elevation with

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washed crushed stone (SCDOT No. 57 or 67) corrected per the recommendations of the project geotechnical engineer. Prepared bearing surfaces for foundations should not be disturbed or left exposed during inclement weather. Saturation of the footing subgrade can cause a loss of strength and increased compressibility. If foundation excavations must remain open overnight or if rainfall becomes imminent while the bearing soils are exposed, we recommend that a 2 to 4-inch thick “mud-mat” of lean (2000 psi) concrete be placed on the bearing soils before placement of reinforcing steel to help protect the bearing soils from further disturbance. Also, concrete should not be placed on frozen subgrades.

5.5 Floor Slabs Ground-level floor slabs may be supported on low-plasticity residual soils or properly placed and compacted fill. Depending on final grades, either a 4-inch layer of compacted Aggregate Base Course (ABC) stone or a 4-inch-thick layer of washed stone (SCDOT No. 57 or 67 gradation), as well as a plastic vapor barrier, should be provided beneath all building floor slabs to provide a capillary break and to help prevent a damp slab condition. The floor slabs should be designed to resist the anticipated dead and live loads. For preliminary purposes, the floor slabs may be designed using a modulus of subgrade reaction (k) of 100 pounds per cubic inch. Higher modulus values may be available, depending on design grades and the building locations.

5.6 Retaining Walls Based on the existing topography, we anticipate below-grade walls (e.g. site retaining walls, basement walls) may be used to achieve grade separation on the site. These walls should be designed to resist lateral earth pressures of backfill soils, in addition to any temporary or long-term surcharge loads, such as cars or trucks adjacent to the walls as well as nearby foundation loads. The "At rest" lateral earth pressure coefficient should be used for walls that are restrained from rotation and the “Active” lateral earth pressure coefficient used when rotation is not restrained. In addition to internal and external stability, we recommend that the global stability of any retaining wall be analyzed. Drainage should be provided behind the walls to reduce the build-up of hydrostatic forces or, in the case of basement walls, should be waterproofed and designed to withstand hydrostatic pressures. The most commonly used site retaining walls are Segmental Retaining Walls (SRWs). SRWs consist of a gravity retaining wall system composed of individual masonry block facing units connected to geogrid material extending through a reinforced zone of soil fill located behind the facing units. Our experience indicates SRWs are one of the most problematic systems in common site development use. The problems are often due to lack of coordination between design and construction, competitive pressures among wall contractors, and lack of wall construction oversight. SRWs should be designed by a registered engineer, and should specifically consider surface drainage, internal drainage,

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internal stability, external stability, global stability, reinforced zone fill materials, retained zone fill materials, and wall deflections, among other things. Once the locations of site SRWs have been determined, additional exploration in these areas should be performed. S&ME offers both SRW design and full time SRW construction observation services. For preliminary design, and assuming that the on-site sandy silts and silty sands observed in the borings are used as backfill against the walls or between geogrid layers if reinforced SRWs are constructed, we recommend the following preliminary parameters:

1. Active Lateral Earth Pressure Coefficient = 0.36 to 0.39 2. At-Rest Lateral Earth Pressure Coefficient = 0.53 to 0.56 3. Passive Lateral Earth Pressure Coefficient = 2.56 to 2.78 4. ф’ = 26 to 28° Angle of Internal Friction of Backfill 5. c = 50 to 75 psf Cohesion of Backfill 6. qall = 2,500 Allowable Bearing Pressure of Foundation Soil 7. ҮM = 120 pcf Moist Soil Unit Weight of Backfill.

For the final design, we recommend shear strength testing of the on-site soils be performed to determine/verify the strength parameters used for retaining wall design.

5.7 Pavements The fine-grained soils typically available for use as structural fill/backfill in the project area are generally poor to marginal for pavement support since they are subject to softening and loss of strength with gradual exposure to moisture. Experience with similar soils indicates typical soaked CBR values of 3 to 5. Plastic clayey or silty soils (CH and MH) are not suitable for direct support of the pavement subgrade due to excessive swell and shrink potential. Typical pavement sections for similar subgrade soil conditions including properly compacted fill, low plasticity residual soils, or suitable existing fill soils (excluding CH & MH) and similar developments are presented in the following table:

Thickness Pavement Type

Material Light-Duty Heavy Duty

Concrete 4 to 6 6 to 8 Rigid Crushed Stone 6 6

Asphalt Concrete 2 to 4 3 to 5 Flexible Crushed Stone (ABC) 6 to 8 8 to 12

Light-duty pavements should be designated for car parking areas and lightly traveled service roads. Heavy-duty pavements should be designated for entrances and exits, access roads, driveways, truck lanes, and areas in front of loading docks and dumpsters. Site specific pavement section thicknesses can be determined once design grades and design traffic information are available, and once additional subgrade testing (e.g., California Bearing Ratio) is performed.

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The early placement of the graded aggregate base course will minimize the deterioration of the prepared soil subgrades. However, some loss of graded aggregate due to rutting and surface contamination may occur prior to final asphalt paving. Some infilling and re-grading of the graded aggregate in conjunction with sweeping with a wire broom may be required. 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.

5.8 Final Geotechnical Exploration The preliminary conclusions and recommendations submitted in this report are based in part upon the data obtained from a limited subsurface exploration program and are intended to provide a general assessment of geotechnical conditions at select locations on the site. Once final grades, building locations, retaining wall and pavement locations have been finalized, we recommend that additional soil test borings and/or other geotechnical tests be performed to develop the geotechnical design and construction recommendations for design and construction purposes.

6.0 LIMITATIONS OF REPORT

The boring locations given in this report should be considered accurate only to the degree implied by the methods used to determine them. The boring logs represent our interpretation of the subsurface conditions based on the field logs, and visual examinations of samples by a staff professional or technician, in addition to tests of the field samples. The lines designating the interfaces between various strata may be gradual. The generalized subsurface strata and profiles described in this report are intended to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized. They have been developed by interpretations of widely-spaced borings. Therefore, actual subsurface conditions may vary from those given between test locations. Groundwater levels have been measured or inferred in the borings at the times and under the conditions stated on the exploration logs in this report. Changes in the groundwater conditions may occur due to variations in rainfall, evaporation, construction activity, surface water runoff, and other site specific factors. Our geotechnical services include storing the samples collected and making them available for inspection for 90 days. The samples are then discarded unless our client requests otherwise.

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The assessment of site environmental conditions and the determination of contaminants in the soil, rock, surface water or groundwater of the site were beyond the scope of this geotechnical study. The recommendations provided in this report are based on our understanding of the project information given in this report and on our interpretation of the surface and subsurface data collected. We have made our recommendations based on our experience with similar subsurface conditions and similar projects. The recommendations apply to the specific project discussed in this report; therefore, any changes in the project information should be provided to us so we may review our conclusions and recommendations and make any appropriate modifications. S&ME should be retained for a general review of the design drawings and specifications to verify that geotechnical recommendations are properly interpreted and implemented. Regardless of the thoroughness of a geotechnical study, there is always a possibility that subsurface conditions will be different from those at boring locations, that conditions will not be as anticipated by the designers or contractors, or that the construction process will alter soil conditions. Therefore, qualified geotechnical personnel should observe construction to confirm that the conditions indicated by the geotechnical borings actually exist. We recommend the owner retain S&ME for this service since we are already familiar with the project, the subsurface conditions at the site, and the intent of the recommendations and design. This report has been prepared for the exclusive use of the client for specific application to the subject project and project site. It has been prepared in accordance with generally accepted geotechnical engineering practice for specific application to this project. The conclusions and recommendations contained in this report are based upon applicable standards of our practice in this geographic area at the time this report was prepared. No other warranty, expressed or implied, is made.

SCALE:

CHECKED BY:

DRAWN BY:

DATE:

FIGURE NO.

1PROJECT NO.: 1351-10-010

AS SHOWN

LAC

BCM

3/17/2010

SITE VICINITY MAPPROPOSED 78-ACRE DEVELOPMENT

LAZY HAWK ROADROCK HILL, SOUTH CAROLINA

SITE

Approximate Site Location

SCALE:

CHECKED BY:

DRAWN BY:

DATE:

FIGURE NO.

2PROJECT NO.: 1351-10-010

1” = 500’

LAC

BCM

3/17/2010

BORING LOCATION PLANPROPOSED 78-ACRE DEVELOPMENT

LAZY HAWK ROADROCK HILL, SOUTH CAROLINA

LEGEND

APPROXIMATE BORING LOCATION

B-3

0’ 250’ 500’

GRAPHIC SCALE

APPROXIMATE PARCEL BOUNDARY

B-2

B-1

B-4

B-5

B-6

B-7

B-10

B-8 B-9

B-11

B-12

INTE

RSTATE

77

HC

RESIDUUM: Very Stiff Red Tan Clayey SILT(MH)

Stiff Red Fine Sandy SILT (ML) with manganesestaining

Boring terminated at 20 feet. Boring dry attermination. Boring dry on 3/1/2010 with a cave-indepth of 15.6 feet. Boring backfilled on 3/1/2010.

Depth measurements are shown to illustrate thegeneral arrangements of soil types encountered atthe boring location. Do not use depthmeasurements for determination of distances orquantities.

18

23

11

12

10

10

STANDARD PENETRATION TEST DATA

(blows/ft)

60WA

TE

R L

EV

EL

10


York County 78-Acre DevelopmentRock Hill, South Carolina

PROJECT:

20

WATER LEVEL:

80

BORING LOG B-01

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0

MATERIAL DESCRIPTION

ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010

NOTES: Standard Penetration Testingperformed with Autohammer.DATE DRILLED: 2/23/10

DRILLING METHOD: 2¼" H.S.A.

LOGGED BY: L. Campos

DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.

THIS LOG IS ONLY A PORTION OF A REPORT PREPARED FOR THE NAMEDPROJECT AND MUST ONLY BE USED TOGETHER WITH THAT REPORT.

BORING, SAMPLING AND PENETRATION TEST DATA IN GENERALACCORDANCE WITH ASTM D-1586.

STRATIFICATION AND GROUNDWATER DEPTHS ARE NOT EXACT.

WATER LEVEL IS AT TIME OF EXPLORATION AND WILL VARY.

BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

Topsoil / Rootmat (3 inches)

FILL: Stiff Brown Fine Sandy CLAY (CL)

RESIDUUM: Stiff to Very Stiff Red Tan Gray SiltyCLAY (CH)

Stiff to Firm Tan Brown Micaceous Fine SandySILT (ML)

Boring terminated at 20 feet. Boring dry attermination. Water level measured at 14 feet on3/1/2010 with a cave-in depth of 16.2 feet. Boringbackfilled on 3/1/2010.


11

14

28

22

11

8


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-2

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

14 feet on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC


FILL: Stiff Red Brown Fine Sandy CLAY (CL)

RESIDUUM: Stiff Red Gray Silty CLAY (CH)

Stiff Red Tan Gray Fine Sandy CLAY (CL)

Stiff Gray Tan Silty CLAY (CH)

Stiff Brown Tan Micaceous Fine Sandy SILT (ML)with manganese staining



11

9

11

15

10

10


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-3

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Very Stiff Red Clayey SILT (MH)

Stiff Red Micaceous Fine Sandy SILT (ML) withmanganese staining



20

18

13

12

10

13


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-4

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Stiff Red Brown Tan Clayey SILT(MH)

Firm to Stiff Red Fine Sandy SILT (ML) withmanganese staining

Boring terminated at 20 feet. Water level measuredat 18 feet at termination. Water level measured at13.3 feet on 3/1/2010 with a cave-in depth of 14.8feet. Boring backfilled on 3/1/2010.


12

13

8

8

8

9


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-5

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

13.3 feet on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Stiff to Firm Red Brown SlightlyMicaceous Fine Sandy SILT (ML) with manganesestaining

Loose Gray Slightly Micaceous Silty Fine SAND(SM)



12

12

8

8

9

10


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-6

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC


RESIDUUM: Stiff to Very Stiff Red Clayey SILT(MH)

Stiff to Firm Red Brown Micaceous Fine SandySILT (ML) with manganese staining



11

19

12

12

7

8


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-7

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Stiff Red Silty CLAY (CH)

Very Stiff Red Clayey SILT (MH)

Stiff to Very Stiff Red Slightly Micaceous FineSandy SILT (ML) with manganese staining



14

17

14

13

12

16


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-8

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

Firm to Stiff Red Brown Fine Sandy SILT (ML) withmanganese staining



12

9

8

8

9

14


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-9

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

FILL: Firm Red Brown Fine Sandy SILT (ML)

FILL: Stiff Red Brown Silty CLAY (CH)

RESIDUUM: Stiff Tan Gray Silty CLAY (CH)

Firm to Stiff Brown Tan Fine Sandy SILT (ML)

Boring terminated at 20 feet. Boring dry attermination. Water level measured at 14.2 feet on3/1/2010 with a cave-in depth of 16 feet. Boringbackfilled on 3/1/2010.


7

13

14

14

8

9


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-10

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

14.2 feet on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Very Stiff Red Brown Clayey SILT(MH)

Stiff to Firm Brown Tan Fine Sandy SILT (ML) withmanganese staining

Boring terminated at 20 feet. Boring dry attermination. Boring dry on 3/1/2010 with a cave-indepth of 15 feet. Boring backfilled on 3/1/2010.


18

17

15

9

8

10


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-11

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

HC

RESIDUUM: Stiff Brown Red Silty CLAY (CH)

Hard to Very Stiff Red Brown Clayey SILT (MH)

Stiff Brown Tan Fine Sandy SILT (ML) withmanganese staining



9

9

32

26

12

10


(blows/ft)

60WA

TE

R L

EV

EL

10



PROJECT:

20

WATER LEVEL:

80

BORING LOG B-12

SA

MP

LE N

O.

SA

MP

LE T

YP

E

ELEVATION:

BORING DEPTH: 20.0


ELE

VA

TIO

N

(fee

t-M

SL)

GR

AP

HIC

LOG

N V

ALU

E

5

10

15

20

DE

PT

H

(fee

t)

DRILL RIG: CME 550X

Dry on 3/1/2010




DRILLER: C. Boyce

30

Page 1 of 1NOTES:

1.

2.

3.

4.





BO

RIN

G L

OG

10-

010

YO

RK

CO

UN

TY

78

AC

RE

DE

VE

LOP

ME

NT

.GP

J S

&M

E.G

DT

3/1

7/1

0

preliminary geotechnical engineering report proposed 78

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