PN92793_-_READY_TO_ADVERTISE_-_geotechnical_report.pdf

United States Army Corps of Engineers

SOF Operations Annex Building

PN 92793

Contact No. W912-PM19-D0003 Delivery Order No. W912PM20F0013

Fort Bragg, North Carolina

Geotechnical Engineering Report

Quality information

Document name AECON No. Ref Prepared for Prepared by Date Reviewed by

Geotechnical Engineering Report

60625564 Final USACE Marco Gravina, PE. 05-27-2021 Victor Omelchenko, PE, DGE

Revision history

Revision Revision date Details Name Position

This document has been prepared by AECOM Limited for the sole use of our client (the “Client”) and in accordance with generally accepted consultancy principles, the budget for fees and the terms of reference agreed between AECOM Limited and the Client. Any information provided by third parties and referred to herein has not been checked or verified by AECOM Limited, unless otherwise expressly stated in the document. No third party may rely upon this document without the prior and express written agreement of AECOM Limited.

Table of Contents

INTRODUCTION AND SCOPE OF WORK .............................................................................. iii

1 EXISTING SITE CONDITIONS AND PROPOSED CONSTRUCTION

1.1 Existing Site Conditions

1.2 Proposed Construction

2 FIELD EXPLORATIONS

2.1 Subsurface Explorations

2.2 Boring Stakeout and Subsurface Utility Clearance

2.3 Drilling Methodology and Sampling

3 SUBSURFACE EXPLORATION RESULTS

3.1 Subsurface Conditions

3.2 Groundwater

3.3 Laboratory Testing

3.4 Corrosivity Testing

3.5 Seismic Design Criteria

3.6 Expected Variations in Subsurface Conditions

4 DESIGN AND CONSTRUCTION RECOMMENDATIONS

4.1 Foundation Recommendations

4.2 Floor Slab Recommendations

4.3 Restrained and Unrestrained Walls

4.4 Pavement Areas

4.5 Existing Underground Utilities

5 CONSTRUCTION CONSIDERATIONS

5.1 Footing Subgrades

5.2 Fill, Pavement and Floor Slab Subgrade Preparation

5.3 Fill Placement and Compaction

5.4 Construction Monitoring

6 LIMITATIONS

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List of Figures and Appendices

Figure 1- Site Vicinity Map

Figure 2- Boring Location Plan

Figure 3- Design Earth Pressures for Restrained Walls

Figure 4- Design Earth Pressures for Unrestrained Walls

Appendix A

Soil Boring Logs (11 Sheets), USCS Soil Identification Sheet (2 Sheet)

Appendix B

Soil Laboratory Test Results (12 Sheets)

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INTRODUCTION AND SCOPE OF WORK

The United States Army Corps of Engineers-Wilmington District (USACE) is planning to build a new

Operations Support Facility (SOF) Annex Building within the premises of the Aberdeen Training

Facility at Fort Bragg, North Carolina.

AECOM’s scope of work for the project included performing a subsurface investigation and preparation of this geotechnical engineering report with the following information:

A. A soil boring location plan;

B. Final soil boring logs including soil descriptions and soil laboratory test results;

C. Results of the soil laboratory testing;

D. Recommendations for foundation support of the proposed building facility;

E. Recommendations for floor slab subgrade preparations;

F. Recommendations for the handling of groundwater in the design and construction;

G. Seismic site classification based on procedures described in the International Building Code

(IBC) 2018 that uses Standard Penetration Test N-values for calculations;

H. Recommended lateral earth pressures for below grade walls and site retaining walls;

I. Recommendations for earthwork requirements, comments regarding the suitability of on-site materials for re-use as structural fill and backfill material, and removal of unsuitable materials ;

J. Comments regarding geotechnical construction considerations that should be considered both in the design and in the construction plans and specifications.

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1 EXISTING SITE CONDITIONS AND PROPOSED CONSTRUCTION

1.1 Existing Site Conditions

The project is located within Phase 3 of the Special Tactics Facility (STF) at Fort Bragg. The

STF is located within the existing Aberdeen Training Facility (ATF) in Hoke County, North

Carolina. The proposed building site is an area designated for a future building at the Phase 3 facility. Therefore, utilities are readily available within a reasonable distance. The approximate site location is illustrated on the Site Vicinity Map included as Figure 1. The site is closely bound on all four sides by existing site elements. An existing drainage swale and steep slope (2h:1V) is located on the northern and western sides of the site. Additionally, an existing communications duct bank is located on the western side of the site very near the proposed building. An existing building (Building 7 SAR Barn), is located 20 feet south of the proposed building and existing building 5 is located east of the site.

The proposed SOF site is presently an undeveloped open lot which has been graded. A comparison of previous grading plans and existing grades indicates that up to about 20 feet of cut were necessary to reach the existing grades. The site is relatively level with existing grades between about El 465 and El 467.

1.2 Proposed Construction

The proposed SOF structure will consist of a 26,250 square feet masonry load bearing and steel framed structure and will have a lowest finished floor elevation at EL. 468.5 feet on the west side and the will eb about a foot lower on the east side of the building. A portion of the building will have one-story and another portion will have two-stories. The two-story portion of the building will cover an approximate footprint of 112 feet by 82 feet, and the one-story multipurpose space will be 100 feet by 70 feet. The two-story portion consists of a composite slab on steel deck supported by steel beams and columns. The roof system for the two-story portion will consist of cold-formed steel trusses supported by steel beams and exterior CMU walls. The structure will be supported on shallow foundations with a floor slab on grade. It is anticipated that the structure will be loaded with maximum building column and wall loads not to exceed

300 kips and 10 kips per linear foot, respectively. As part of the new development, paved driveways and parking areas will be constructed. it is anticipated that minimal cuts and fills will be needed to reach the proposed floor slab grade and pavement subgrades. A concrete retaining wall was added northwest of the building as part of the Value Engineering study. The wall will be a concrete wall with a maximum height of about 11 feet at its highest point.

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2 FIELD EXPLORATIONS

2.1 Subsurface Explorations

AECOM conducted a subsurface investigation program at the proposed SOF Annex Building site.

Four soil borings, labeled B-1 through B-4, were drilled within the approximate proposed building footprint. Boring B-5 was drilled in the proximity of the proposed retaining wall. Boring B-6 was intended to be drilled on the slope behind the proposed retaining wall. However, boring B-6 was not drilled due to access and drill rig set up safety issues. The approximate boring locations are illustrated on the Boring Location Plan included as Figure 2. Borings B-1, B-2 and B-4 were drilled to a depth of 30 feet below existing grades, Boring B-3 was drilled to a depth of 100 feet below grade and Boring B-5 was drilled to a depth of 35 feet. The soil test boring logs are included in

Appendix A.

2.2 Boring Stakeout and Subsurface Utility Clearance

The boring locations and elevations were surveyed by AECOM’s survey crew. An excavation permit was obtained from the Fort Bragg Department of Public Works (DPW) prior to drilling the borings to mark the existing underground utilities around the staked boring locations. An AECOM representative was present at the site during utility clearance by the DPW personnel. Additionally, the drilling subcontractor contacted the North Carolina 811 One Call service to clear the boring locations.

The ground surface elevations at the boring locations and coordinates are shown on the boring logs included in Appendix A. The boring locations are illustrated on the Boring Location Plan included as Figure 2.

2.3 Drilling Methodology and Sampling

GET Solutions, Inc. (a Terracon Company) of Elizabeth City, North Carolina drilled the soil test borings on April 14th and April 15th, 2021. The borings were drilled with a track mounted CME-

45C drill rig. The borings were drilled using 3-1/4 inch diameter continuous flight hollow stem augers and mud rotary drilling methods to advance the borings. Representative soil samples were obtained using a two-inch outside diameter split-barrel spoon sampler in general accordance with ASTM D1586 standards. Standard penetration tests (SPTs) were performed by driving the split-spoon sampler into the soil a distance of 24 inches over four six-inch intervals by means of a 140-pound hammer falling 30 inches. The number of hammer blows required to drive the sampler through the second and third six-inch intervals (i.e., the N-values) for each sample are indicated on the soil test boring logs included in Appendix A. Soil samples were obtained continuously in the borings in the upper 30 feet of soil overburden and every five feet below the upper 30 feet. The N-values provide an indication of the in-place density (granular materials) and consistency (cohesive materials) of the soils. The borings were backfilled after the groundwater measurements were obtained.

After recovery, the soil samples were removed from the sampler and visually classified by a senior geotechnical engineer from our office. Representative portions of the soil samples were sealed in glass jars and retained for further review. The visual classifications were based on

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texture and plasticity, in accordance with the Unified Soil Classification System (USCS). A brief description of the USCS is also included in Appendix A.

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3 SUBSURFACE EXPLORATION RESULTS

3.1 Subsurface Conditions

The materials encountered during the subsurface exploration are described further below for the purposes of our discussions in this report. It should be noted that these descriptions do not imply the continuity of the materials encountered in the borings. The descriptions of the materials have been established to characterize similar subsurface conditions based on material gradations. The subsurface materials encountered in the test borings, along with the range of Standard Penetration Test (SPT) N-Values are described in the following paragraphs.

Existing fill soils were encountered below the ground surface in all the borings. The existing fill extended between about 1 to 2.5 feet below existing grades or between about EL 463.5 and EL 466 feet. The existing fill generally consists of very loose to medium dense Poorly

Graded Sand (SP-SM) with silt and Poorly Graded Sand (SP) and Well Graded Sand (SW-

SM) with gravel and silt. The Standard Penetration Test (SPT) N-value within the existing fill varied between 4 blows per foot (bpf) and 13 bpf

Natural sandy and clayey soils were encountered below the existing fill material to the maximum depth investigated by the borings. The natural sandy soils consist of loose to very dense Poorly Graded Sand (SP-SM) with silt, Silty Sand (SM), Poorly Graded Sand (SP) and

Clayey Sand (SC). The natural clayey soils consist of Sandy Lean Clay (CL) and Fat Clay with sand (CH). The SPT N-values of the natural soils varied between 5 bpf and 51 bpf in the sands

(loose to very dense) and between 14 bpf to 21 bpf in the clay soils (stiff to very stiff).

3.2 Groundwater

Groundwater measurements were obtained during drilling operations, upon completion of the borings and up to about 24 hours after drilling. A 1- inch diameter temporary PVC standpipe was installed in borings B-1, B-2 and B-5 to prevent the boring sidewalls from caving in. It is noted that mud rotary drilling methods was used drill Borings B-3 and B-4 which required the introduction of drilling fluid. These borings were drilled the last day of the drilling operations and were backfilled at the end of the day. The groundwater observations made in the borings are included in the soil boring logs included in Appendix A and are summarized below:

Soil Boring

Number

Approximate

Groundwater Depth

(feet)

Approximate

Groundwater Elevation

(feet)

Boring Cave

Depth (feet)

B-1 19.7 447.3 *

B-2 19.8 447.2 *

B-3 N/A -- **

B-4 N/A -- **

B-5 18.6 446.4 *

*Installed a 1-inch diameter temporary PVC standpipe to obtain the 24-hour groundwater levels.

**Mud rotary drilling methods was used which required the introduction of drilling fluid. Boring backfilled upon completion.

Perched water conditions may be encountered during construction due to the presence of fine-grained soils interbedded with free-draining sandy soils. It is possible that stabilized

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groundwater levels are higher than those encountered during drilling. It should be noted that fluctuations in groundwater levels may occur as a result of seasonal variations in rainfall, proximity of the site to large bodies of water, evaporation, construction activity, surface runoff, and other site-specific factors.

3.3 Laboratory Testing

Soil samples were transported to AECOM’s Germantown, Maryland, office for further observation before samples were selected to undergo soil laboratory testing. Selected split-spoon soil samples were tested by Jay Kay Testing Inc., to determine the physical and engineering properties of the on-site soils. The soil laboratory tests were conducted in accordance with applicable ASTM standards and specifications. The testing included moisture content determinations (ASTM D2216), Atterberg Limits tests (ASTM D4318), mechanical gradation analyses (ASTM D6913), and a Modified Proctor test (ASTM D1557). The soil laboratory test results are presented in Appendix B and are incorporated in the boring logs included in Appendix A.

3.4 Corrosivity Testing

A composite soil sample obtained from boring B-3 was tested to determine the corrosion potential of the soils in the project area. The sample was obtained from approximately 2 to 6 feet below the ground surface. The samples were tested by Jay Kay Testing Inc.

pH testing of soils was conducted in general accordance with the AASHTO T-289 method. Soil resistivity testing was conducted in general accordance with the AASHTO T-288. Sulfate and

Chloride concentration testing was performed in general accordance with AASHTO T-290B and AASHTO T-291A, respectively. The oxidation-reduction potential of the soil was conducted in general accordance with ASTM D-1498 The soil laboratory test results are included in

Appendix C and are summarized in the table below.

Table 1: Corrosion Test Results Summary

Boring pH Chloride (ppm)

Sulfate ( ppm)

Sulfides (presence)

Resistivity (ohm-cm)

Oxidation- Reduction Potential

(mV)

B-3 4.67 9 6 ND 14,500 308

ND=Not Detected

The geochemical properties of the soils at the project site need to be considered in the final design of the facilities of the project, including, sewers, structures, and foundations. AWWA standard C-105 (Polyethylene Encasement for Ductile-Iron Pipe System) was used to assess the corrosion potential of the soil based on the soil resistivity, redox potential, pH, sulfides concentration, and moisture content. Based on the test results, the onsite soils are not considered to be corrosive to ductile iron pipe.

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The test results indicated sulfate concentrations of 9 parts per million (ppm) in the soils at the site. Based on the American Concrete Institute (ACI) 318, there is no concern of injurious sulfate attack on concrete at this level of sulfate concentration. Concrete can be designed to meet the criteria for Exposure Category S0 as defined in ACI 318. Final selection of the cement grade and approval of the concrete mix should be performed by the structural engineer.

3.5 Seismic Design Criteria

The seismic site classification was analyzed in accordance with Section 1613.2.2 of the 2018

International Building Code (IBC) which in turn refers to the American Society of Civil Engineers

(ASCE) 7-16 standard, chapter 20. We used the SPT N-value method for classification based on the upper 100 feet of the site soil profile. Soil boring B-3 was drilled to a depth of 100 feet to obtain the soil profile at the site. The calculated weighted N-value is 15. According to the IBC

2018 and the ASCE 7-16 standard, Table 20.3-1, the site can be classified as Site Class D.

Liquefaction is a phenomenon where loose, granular soils below the groundwater table experience a reduction of shear strength under strong and extended earthquake shaking over successive cycles of ground motion. Therefore, liquefaction is most likely to occur in areas with shallow groundwater, where the subsurface profile consists of relatively thick layers of loose granular material and when the site is subjected to strong and sufficiently long ground motions.

Shallow groundwater or loose sands were not encountered in the upper 65 feet in the borings drilled at the site during the site investigation. Based on the SPT N-values, the groundwater observations obtained from the soil borings and our analysis using the software Liquefaction Pro the probability of liquefaction is very low.

3.6 Expected Variations in Subsurface Conditions

Interpretation of general subsurface soil conditions presented herein is based on the soil and groundwater conditions encountered in the soil borings drilled at the site. Although representative portions of the samples taken were tested, subsurface conditions may vary between exploration locations. If conditions are found to be different from those observed in the borings, recommendations contained in this report should be re-evaluated by AECOM and confirmed in writing. Since the groundwater levels are expected to fluctuate with rainfall, season, temperature, climate, construction in the area, etc., groundwater conditions at the time of construction may be different from those found during the time of the exploration.

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4 DESIGN AND CONSTRUCTION RECOMMENDATIONS

4.1 Foundation Recommendations

Up to 2.5 feet of existing fill material was encountered in the soil borings. The existing fill is believed to be associated with the previous grading of the site and it is likely that the existing fill was not properly compacted or with minimal compaction effort. Therefore, the existing fill is not considered suitable for direct support of shallow foundations due to the risk for larger than normal foundation settlement. New spread footing foundations should be placed on new compacted structural fill after complete removal and replacement of the existing fill. As an alternative, the new footings may be extended through the existing fill and placed on natural soils after complete removal of the existing fill soils. Existing fill soils can also be undercut and can be replaced with lean concrete or crushed stone, such as American Association of State

Highway and Transportation Officials (AASHTO) No. 57 stone.

Footings founded on firm natural soils or new compacted structural fill may be designed using a net allowable soil bearing pressure of up to 2,500 (psf). We estimate that settlement of spread footings should not exceed approximately one inch. Differential settlement between new foundation elements should not exceed half this amount. The estimated settlements are expected to be within acceptable tolerances per typical building practices. Spread footings should bear at least 24 inches below the adjacent exterior finished grades for frost protection.

Continuous wall footings should have a minimum width of 24 inches, and isolated column footings should have a minimum width of 30 inches. The minimum widths are recommended to provide a margin of safety against a local or punching shear failure of the foundation soils.

The bases of all foundation excavations should be free of water and loose soil prior to the placement of concrete. The foundation subgrades should be observed and approved by a qualified geotechnical engineer. All undercuts, if necessary, should be evaluated and observed by the Third Party Inspection Agency geotechnical engineer during construction.

4.2 Floor Slab Recommendations

Based on the soil boring data, the soils at the proposed floor slab subgrade of the proposed

SOF structure are expected to consist of firm natural soils, existing fill or new compacted fill.

These soils are generally considered suitable for direct ground floor slab support. However, the existing fill material may loose in areas and some undercutting and replacement of soft soils with new compacted fill or crushed stone such as AASHTO No. 57 crushed stone should be anticipated. The adequacy of subgrades should be determined by a qualified geotechnical engineer during construction.

All debris, organic and soft soils near the final floor slab subgrade as a result of construction operations should be stripped and removed prior to placement of underfloor stone. A six-inch minimum thickness of washed gravel or crushed stone meeting the requirements of AASHTO

No. 57 stone should be placed below floor slabs on-grade to serve as a capillary break.

A vapor barrier consisting of a minimum six-mil polyethylene sheeting meeting ASTM E1745 standards should be placed on top of the granular layer before the placement of concrete to prevent intrusion of the concrete into the granular base and to provide an additional barrier

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against moisture migration. It is considered that an underfloor subdrainage will not be necessary. Based on the groundwater observations made in the soil borings, the groundwater is expected to be below the floor slab level between about EL 446 and EL. 447.

Also, in order to minimize the development of any shrinkage cracks near the surface of the slab, we recommend that wire mesh (fiber or welded wire fabric) reinforcement be included in the design of the floor slab. The wire mesh should be located in the top half of the slab to be effective.

The design of earth-supported floor slabs should be based on a modulus of subgrade reaction (K) of 100 pounds per cubic inch (pci).

4.3 Restrained and Unrestrained Walls

Non-yielding below-grade walls such as elevator pit walls that are restrained should be designed for at-rest earth pressures to resist backfill and surcharge loads. Assuming the new backfill consists of granular soils meeting the backfill material requirements included in this report, restrained walls should be designed using an equivalent fluid pressure of 60H (psf), where H is the total wall height. For surcharge loads, 50 percent of any uniform area surcharge placed at the top of the wall may be assumed to act as a uniform horizontal pressure over the entire height of the wall. Below-grade wall design recommendations are included in Figure 3 included in this report.

We understand that a site retaining wall was added, as part of the value engineering, at the northwest end of the site. This wall is not expected to exceed about 11 feet in height at its highest point. Unrestrained site retaining walls with level backfill conditions can be designed for an equivalent fluid pressure of 40H (psf). Thirty-three percent of any surcharge placed within a horizontal distance from the top of the wall equal to the wall height may be assumed to act as a uniform horizontal pressure over the entire height of the wall. Retaining walls that are not restrained at the top and that have a sloping backfill above the top of the wall may be designed for an equivalent fluid pressure of 64H (psf), provided the slope above the wall is

2H:1V or flatter. Uniform horizontal pressure over the entire height of the wall due to surcharge loads may be assumed to be 54 percent of any surcharge placed within a horizontal distance from the top of the wall equal to the wall height. Retaining walls with level or sloped backfill may be designed to include a passive equivalent fluid pressure of 360D (psf). Retaining wall recommendations are included in Figure 4. A coefficient of friction of 0.45 may be used for sliding resistance at the soil/concrete interface.

The recommended equivalent fluid pressure values do not include lateral pressures due to hydrostatic water pressures generated by infiltrating surface water that may accumulate behind the walls. Therefore, wall backfill materials should be free-draining, and provisions should be made to remove excess water that may accumulate behind the retaining wall.

Backfill requirements are included in Section 5 of this report. A perforated 4-inch diameter drainage pipe should be placed at the base of the retaining wall and should be surrounded by at least 6 inches of AASHTO No. 57 crushed stone and wrapped with geotextile filter cloth.

Retaining wall drainage pipes should be directed to flow by gravity away from the structures.

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It is recommended to waterproof the elevator pit wall. Typical foundation subdrainage details are presented in Figure 4.

As an alternative, weep holes may be installed at the bottoms of the walls if the subdrainage pipe is substituted with weep holes. The weep holes should consist of 3-inch diameter PVC pipe installed at 10 feet intervals along the walls. The weep holes should be covered on the backfill side of the retaining wall with a permeable geotextile filter cloth to prevent the migration of fines through the weep holes.

Site retaining walls may be designed for a maximum soil bearing pressure of 2,500 psf when founded directly on new compacted soil or natural soils. Subgrades consisting of existing fill material should be undercut. The undercut soils should be replaced with new compacted structural fill or AASHTO No. 57 stone. Retaining wall foundations should bear at least 24 inches below the adjacent exterior finished grades for frost protection. The embedment depth should be adjusted based on structural requirements. Retaining wall foundation subgrades should be observed and approved by the Third Party Inspection Agency geotechnical engineer during construction.

The proposed retaining wall should be checked for global slope stability. An attempt was made to drill a soil boring, B-6, on the retained side of the wall. However, due to access and drill rig set up safety issues, boring B-6 was not drilled. Global slope stability analysis was not part of our scope of services.

4.4 Pavement Areas

Paved driveways and parking areas will be constructed as part of the new development. It is anticipated that the proposed pavement subgrades will consist of new compacted fill or natural soils. These soils are generally considered suitable for pavement support provided the subgrades are prepared as recommended in section 5.2 of this report.

A preliminary California Bearing Ratio (CBR) value of 5 may be used for preliminary pavement design. The CBR value should be verified during construction once the pavement subgrades are established. At that time, soil laboratory CBR tests should be performed on representative samples recovered from the finished subgrades to provide pavement subgrade parameters for use in the final pavement design. Pavement design recommendations were not part of the scope.

All pavement materials should be in accordance with the Standard Specifications for Construction and Materials of the North Carolina Department of Transportation, State Highway Administration, and any applicable local standards.

4.5 Existing Underground Utilities

Several underground utility lines are present within the proposed SOF Annex Facility site. It is recommended that re-routing or abandonment of any utility line(s) present within the SOF structure’s footprint be performed. If removed, the excavations can be backfilled with new compacted structural fill. If the utilities are abandoned, the pipes should be grouted-in-place.

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5 CONSTRUCTION CONSIDERATIONS

5.1 Footing Subgrades

All footing excavations should extend to suitable bearing materials, and final bearing subgrades should be observed and approved by the third party testing agency prior to the placement of new structural fill or concrete to verify their suitability to provide foundation support, as recommended herein. All localized unsuitable material present at the footing subgrades should be completely removed and replaced with AASHTO No. 57 crushed stone or lean concrete, as recommended in this report. A maximum allowable slope of 1H:1V should be maintained between the bottom edges of adjacent footings. The third party testing agency should monitor and document all footing subgrade undercuts, if any.

Due to the presence of sandy and clayey soils at the site, perched groundwater may be encountered during construction, particularly during undercutting operations to remove soft or loose upper soil materials. The contractor should be prepared to provide localized construction dewatering consisting of submersible pumps in gravel sumps and/or collector trenches. If foundations cannot be poured the same day they are excavated, three-inch mud mats should be placed over soil subgrades to protect the footing subgrade soils.

5.2 Fill, Pavement and Floor Slab Subgrade Preparation

The site will require cut and fill operations to reach final site grades. At the onset of any site grading, the entire fill area should be stripped of vegetation, asphalt, roots, topsoil, construction debris, and any deleterious materials. Following the removal of any unsuitable material, areas designated for site fill, floor or pavement subgrades should be proof-rolled with a 10-ton loaded dump truck or construction equipment of equal weight. The third party testing agency representative should be present to verify the suitability of the subgrades to receive fill or base course material. Up to approximately 2.5 feet of existing fill was encountered in the borings and some undercut and replacement may be necessary in some areas. The upper 12 inches of soil at the pavement subgrades should be scarified and re-compacted prior to placement of base course material.

Fill and pavement subgrades consisting of existing fill soils may be soft and yielding in some areas. Where moisture conditioning and re-compaction do not create stable subgrades, undercutting of these soils may be necessary to stabilize the subgrades to achieve the structural fill compaction requirements. The depth of undercutting, if necessary, will vary depending on the actual soil conditions encountered and should be determined in the field. We recommend establishing a budget for the undercutting of soft and yielding existing fill and natural soils. All undercuts, if necessary, should be approved and performed under the observation of the Third

Party testing agency geotechnical engineer.

5.3 Fill Placement and Compaction

All new compacted structural fill and backfill should be placed in loose lifts not exceeding eight inches in thickness and should be compacted to at least 95 percent of the maximum dry density, in accordance with ASTM D1557. In general, the moisture content of the fill materials should be

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maintained within 3 percent of the optimum moisture content per ASTM D698. The pavement subgrades should be scarified and dried or moistened as required and re-compacted to a minimum of 100 percent accordance with ASTM D1557 for a minimum depth of 12 inches before the base course and pavement materials are installed. Compacted fill material placed below the upper 12 inches below the pavement subgrades should be compacted to at least 95 percent of the maximum dry density in accordance with ASTM D1557. Materials to be used as compacted fill in the building and pavement areas should be classified as CL, ML, SM, or more granular although backfill behind walls should classify as SM or more granular. Also, soils should have a Liquid Limit (LL) and Plastic limit (PI) of less than 40 and 20, respectively. Backfill material to be used behind below grade walls should be classified as SM or more granular and should have a LL and PI less than 40 and 15, respectively.

Off-site borrow material may be required to be used as compacted fill material. Portions of the onsite soils encountered that classify as CL, ML, SM, or more granular may be suitable for reuse as compacted structural fill, provided they meet the above requirements and are free of organic matter and other deleterious matter. Some moisture conditioning of these soils will be required to achieve the compaction requirements. Soils classified CH, and MH are not considered suitable for reuse as compacted fill or backfill. The suitability of the onsite soils for reuse as fill and backfill should be determined by the third party testing agency during construction.

5.4 Construction Monitoring

Monitoring of the construction of the project is strongly recommended to address quality control/quality assurance issues and to promptly address non-conforming construction. Full-time construction monitoring should be provided during all aspects of the earthwork, excavation and construction by a third party testing agency that is familiar with the design and construction criteria for the project. The monitoring should include documentation of all aspects of the excavation, subgrade conditions, subgrade preparation, placement and compaction of fill and backfill, and other relevant construction issues.

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6 LIMITATIONS

Interpretation of general subsurface soil conditions presented herein is based on the soil and groundwater conditions encountered in the limited number of soil borings. Although representative portions of the samples taken were tested, subsurface conditions may vary outside of exploration locations. This report does not reflect any variations that may occur outside of boring locations or across the site in areas not sampled. The nature and extent of such variations may not become evident until construction. Groundwater conditions during construction may be different from the observations made in the borings.

This report has been prepared for the specific application to the project discussed and in accordance with generally accepted geotechnical engineering practices. No warranty, express or implied, is provided. In the event that any 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 will not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing by AECOM.

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Figure 1- Site Vicinity Map

Figure 2- Boring Location Plan

Figure 3- Design Earth Pressures for Restrained Walls

Figure 4- Design Earth Pressures for Unrestrained Walls

Appendix A

Soil Boring Logs (11 Sheets), USCS Soil Identification Sheet (2 Sheet)

0.0 - 2.5 ft: (FILL) Moist, medium dense, dark gray with brown, Poorly Graded Sand With Silt

2.5 - 4.0 ft: Moist, medium dense, orangish brown, SILTY SAND

4.0 - 6.0 ft: Moist, medium dense, orangish brown, POORLY GRADED SAND WITH SILT

6.0 - 18.0 ft: Moist, loose, orangish brown and dark gray, SILTY SAND

7.0 ft: changes to orangish brown

8.5 ft: changes to dark orangish brown

10.0 ft: changes to medium dense

14.0 ft: changes to loose

16.0 ft: changes to medium dense

18.0 - 22.0 ft: Moist, medium dense, orangish brown, POORLY GRADED SAND WITH SILT

SP-

SM

SM

SP-

SM

SM

SP-

SM

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

6.0ft: Installed 4" HW casing to 6' bgs and began mud rotary drilling

7.2

5.4

18.4

24.5

(71%)

(67%)

(71%)

(79%)

(58%)

(75%)

(63%)

(38%)

(50%)

(46%)

3- 6- 7- 8 (N=13)

8- 10- 9- 8 (N=19)

7- 6- 5- 6 (N=11)

3- 4- 3- 3 (N=7)

3- 4- 4- 8 (N=8)

6- 5- 6- 6 (N=11)

6- 6- 6- 6 (N=12)

1- 4- 6- 6 (N=10)

5- 6- 7- 8 (N=13)

9- 7- 8- 7 (N=15)

HAMMER TYPE/WEIGHT: Auto Hammer/140lbs Date

DRILL RIG: CME-45C (Track)

BIT TYPE/SIZE: Tricone Roller/NA

CHECKED BY: Ariana White

Date Time Groundwater Observations

19.710:3004-15-2021

DRILL METHOD: Mud Rotary

Event

LOGGED BY: Jocelyn Kaselow

DRILLER: Tim Donahue

DATE STARTED: 4/14/2021

DATE COMPLETED: 4/14/2021

DRILLING CONTRACTOR: GET Solutions, CASING TYPE: Steel

COORDINATES: N 498902.8532 E 1889856.0663

CASING SIZE:

Depth (ft)

BOREHOLE DEPTH: 30.0 FT

SURFACE ELEVATION: 467.00 FT

Cave in Depth (ft)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 1 of 2

A E

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IL

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(1

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IG

N .G

D T

/1

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R

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-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-1

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T U

M

18.0 - 22.0 ft: Moist, medium dense, orangish brown, POORLY GRADED SAND WITH SILT(continued)

22.0 - 27.6 ft: Moist, medium dense, orangish brown, SILTY SAND

26.0 ft: changes to loose

27.6 - 29.6 ft: Moist, loose, light orangish gray, POORLY GRADED SAND WITH SILT

28.0 ft: changes to medium dense

29.6 - 30.0 ft: Moist, medium dense, orangish brown, SILTY SAND Boring completed at 30.0 FT on 4/14/2021 at

15:30 HOURS.

A 1-inch diameter temporary standpipe was installed to collect 24-hour water level reading. The standpipe was removed after the groundwater measurement was obtained.

The boring backfilled with spoils/bentonite grout on 4/15/2021.

SP-

SM

SM

SP-

SM

SM

S-11

S-12

S-13

S-14

S-15

(42%)

(46%)

(46%)

(50%)

(58%)

5- 6- 7- 7 (N=13)

5- 5- 7- 7 (N=12)

3- 5- 6- 5 (N=11)

3- 4- 6- 7 (N=10)

6- 7- 11- 17 (N=18)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 2 of 2

A E

C O

M S

O

IL

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C K

A E

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M -G

E O

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B R

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G S

O F

(1

G

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IG

N .G

D T

/1

1/

R

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-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-1

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

0.0 - 2.5 ft: (FILL) Moist, loose, light brown to brown, Poorly Graded Sand With Silt

0.5 ft: changes to orangish brown

1.0 ft: changes to light brown to dark brown

2.5 - 10.0 ft: Moist, medium dense, orangish brown, WELL GRADED GRAVEL WITH SILT

9.7 ft: changes to contains a 3" layer of light orangish brown, fine to coarse, Poorly Graded Sand (SP)

10.0 - 30.0 ft: Moist, medium dense, light orangish brown, POORLY GRADED SAND

WITH SILT

SP-

SM

SW-

SM

SP-

SM

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

6.0ft: Installed 4" HW casing to 6' bgs and began mud rotary drilling

6.4

4.8

20.2

13.1

20.7

(75%)

(88%)

(67%)

(71%)

(54%)

(54%)

(50%)

(58%)

(42%)

(42%)

2- 3- 4- 5 (N=7)

5- 8- 9- 10 (N=17)

7- 9- 9- 13 (N=18)

7- 10- 9- 8 (N=19)

6- 7- 8- 8 (N=15)

8- 8- 9- 10 (N=17)

5- 6- 8- 7 (N=14)

5- 7- 5- 5 (N=12)

2- 4- 7- 7 (N=11)

4- 5- 6- 5 (N=11)

HAMMER TYPE/WEIGHT: Auto Hammer/140lbs Date

DRILL RIG: CME-45C (Track)

BIT TYPE/SIZE: Tricone Roller/NA

CHECKED BY: Ariana White

Date Time Groundwater Observations

19.810:2504-15-2021

DRILL METHOD: Mud Rotary

Event

LOGGED BY: Jocelyn Kaselow

DRILLER: Tim Donahue

DATE STARTED: 4/14/2021

DATE COMPLETED: 4/14/2021

DRILLING CONTRACTOR: GET Solutions, CASING TYPE: Steel

COORDINATES: N 498908.8932 E 1889701.1336

CASING SIZE:

Depth (ft)

BOREHOLE DEPTH: 30.0 FT

SURFACE ELEVATION: 467.00 FT

Cave in Depth (ft)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 1 of 2

A E

C O

M S

O

IL

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C K

A E

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E O

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B R

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G S

O F

(1

G

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IG

N .G

D T

/1

1/

R

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-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-2

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

10.0 - 30.0 ft: Moist, medium dense, light orangish brown, POORLY GRADED SAND WITH SILT(continued)

Boring completed at 30.0 FT on 4/14/2021 at

13:45 HOURS.

A 1-inch diameter temporary standpipe was installed to collect 24-hour water level reading. The standpipe was removed after the groundwater measurement was obtained.

The boring backfilled with spoils/bentonite grout on 4/15/2021.

SP-

SM

S-11

S-12

S-13

S-14

S-15

(42%)

(50%)

(50%)

(54%)

(46%)

4- 5- 6- 6 (N=11)

5- 7- 10- 11 (N=17)

9- 11- 11- 14 (N=22)

10- 10- 11- 9 (N=21)

6- 9- 11- 14 (N=20)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 2 of 2

A E

C O

M S

O

IL

R O

C K

A E

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M -G

E O

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C H

_F T

B R

A G

G S

O F

(1

G

P J

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IG

N .G

D T

/1

1/

R

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-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-2

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

0.0 - 1.0 ft: (FILL) Moist, loose, dark brown, Poorly Graded Sand With Silt

1.0 - 20.0 ft: Moist, loose, light orangish brown, POORLY GRADED SAND

6.0 ft: changes to medium dense

10.0 ft: changes to orangish brown

12.0 ft: changes to medium dense

18.0 ft: changes to contains est. <5% fine to coarse gravel

20.0 - 38.0 ft: Moist, medium dense, orangish brown, SILTY SAND

38.0 - 43.0 ft: Moist, medium dense, light orangish brown to tan, POORLY GRADED

SAND WITH SILT

SP-

SM

SP

SM

SP-

SM

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

S-11

S-12

S-13

S-14

S-15

S-16

S-17

6.0ft: Installed 4" HW casing to 6' bgs and began mud rotary drilling

4.5

4.2

14.7

17.9

19.3

(71%)

(75%)

(67%)

(58%)

(50%)

(46%)

(54%)

(63%)

(50%)

(54%)

(46%)

(46%)

(54%)

(46%)

(54%)

(50%)

(46%)

3- 3- 4- 5 (N=7)

6- 3- 4- 3 (N=7)

2- 3- 3- 5 (N=6)

3- 6- 7- 8 (N=13)

4- 4- 5- 4 (N=9)

4- 4- 4- 4 (N=8)

4- 5- 6- 6 (N=11)

4- 6- 6- 8 (N=12)

6- 7- 7- 8 (N=14)

3- 7- 8- 8 (N=15)

6- 8- 12- 13 (N=20)

5- 6- 9- 8 (N=15)

6- 7- 8- 7 (N=15)

6- 5- 9- 7 (N=14)

3- 6- 6- 7 (N=12)

6- 8- 11- 10 (N=19)

7- 8- 8- 8 (N=16)

HAMMER TYPE/WEIGHT: Auto Hammer/140lbs Date

DRILL RIG: CME-45C (Track)

BIT TYPE/SIZE: Tricone Roller/NA

CHECKED BY: Ariana White

Date Time Groundwater ObservationsDRILL METHOD: Mud Rotary

Event

LOGGED BY: Jocelyn Kaselow

DRILLER: Tim Donahue

DATE STARTED: 4/15/2021

DATE COMPLETED: 4/15/2021

DRILLING CONTRACTOR: GET Solutions, CASING TYPE: Steel

COORDINATES: N 498969.1041 E 1889709.2256

CASING SIZE:

Depth (ft)

BOREHOLE DEPTH: 100.0 FT

SURFACE ELEVATION: 467.00 FT

Cave in Depth (ft)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility

PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 1 of 3

A E

C O

M S

O

IL

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C K

A E

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M -G

E O

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_F T

B R

A G

G S

O F

(1

G

P J

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_P R

O

JE

C T

-D E

S

IG

N .G

D T

/1

1/

R

E V

-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-3

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

38.0 - 43.0 ft: Moist, medium dense, light orangish brown to tan, POORLY GRADED SAND WITH SILT(continued)

43.0 - 44.4 ft: Moist, stiff, light gray, FAT

CLAY WITH SAND

44.4 - 58.0 ft: Moist, medium dense, light gray, SILTY SAND

48.0 ft: changes to dense

53.0 ft: changes to medium dense

58.0 - 68.0 ft: Moist, loose, light gray, POORLY GRADED SAND WITH CLAY

64.5 ft: changes to contains red laminations

68.0 - 93.0 ft: Moist, dense, dark red and orangish brown, SILTY SAND

73.0 ft: changes to light gray dark red

78.0 ft: changes to light gray with orangish brown

83.0 ft: changes to very dense

SP-

SM

CH

SM

SP-

SC

SM

S-18

S-19

S-20

S-21

S-22

S-23

S-24

S-25

S-26

(83%)

(46%)

(46%)

(88%)

(71%)

(83%)

(96%)

(92%)

(75%)

1- 4- 9- 12 (N=13)

12- 23- 18- 11 (N=41)

5- 6- 8- 6 (N=14)

4- 4- 2- 3 (N=6)

2- 3- 2- 4 (N=5)

2- 3- 7- 10 (N=10)

4- 3- 6- 7 (N=9)

5- 3- 4- 7 (N=7)

34- 23- 29- 29 (N=52)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 2 of 3

A E

C O

M S

O

IL

R O

C K

A E

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M -G

E O

T E

C H

_F T

B R

A G

G S

O F

(1

G

P J

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_P R

O

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IG

N .G

D T

/1

1/

R

E V

-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-3

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

68.0 - 93.0 ft: Moist, dense, dark red and orangish brown, SILTY SAND(continued)

93.0 - 100.0 ft: Moist, medium dense, light orangish gray, CLAYEY SAND

Boring completed at 100.0 FT on 4/15/2021 at

13:30 HOURS.

Boring backfilled with spoils/ bentonite-grout at the end of the day.

Since mud rotary methods were used, groundwater measuements were not obtained.

SM

SC

S-27

S-28

S-29

(54%)

(33%)

(46%)

17- 15- 24- 30 (N=39)

13- 10- 15- 13 (N=25)

6- 8- 11- 12 (N=19)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 3 of 3

A E

C O

M S

O

IL

R O

C K

A E

C O

M -G

E O

T E

C H

_F T

B R

A G

G S

O F

(1

G

P J

A E

C O

M -G

E O

T E

C H

_P R

O

JE

C T

-D E

S

IG

N .G

D T

/1

1/

R

E V

-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-3

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

0.0 - 1.0 ft: (FILL) Moist, medium dense, light brown to brown, Poorly Graded Sand

1.0 - 30.0 ft: Moist, medium dense, orangish brown, POORLY GRADED SAND WITH SILT

2.0 ft: changes to loose

4.0 ft: changes to light orangish brown orangish brown

6.0 ft: changes to medium dense

14.0 ft: changes to loose

18.0 ft: changes to orangish brown

SP

SP-

SM

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

6.0ft: Installed 4" HW casing to 6' bgs and began mud rotary drilling

5.3

5.7

16.2

16.6

(63%)

(79%)

(79%)

(42%)

(50%)

(42%)

(46%)

(42%)

(42%)

(29%)

3- 6- 7- 8 (N=13)

7- 5- 4- 4 (N=9)

3- 4- 4- 4 (N=8)

3- 6- 5- 5 (N=11)

4- 6- 6- 5 (N=12)

6- 7- 7- 7 (N=14)

4- 5- 6- 7 (N=11)

5- 5- 5- 5 (N=10)

6- 4- 5- 4 (N=9)

1- 4- 3- 3 (N=7)

HAMMER TYPE/WEIGHT: Auto Hammer/140lbs Date

DRILL RIG: CME-45C (Track)

BIT TYPE/SIZE: Tricone Roller/NA

CHECKED BY: Ariana White

Date Time Groundwater ObservationsDRILL METHOD: Mud Rotary

Event

LOGGED BY: Jocelyn Kaselow

DRILLER: Tim Donahue

DATE STARTED: 4/15/2021

DATE COMPLETED: 4/15/2021

DRILLING CONTRACTOR: GET Solutions, CASING TYPE: Steel

COORDINATES: N 498980.672 E 1889839.4363

CASING SIZE:

Depth (ft)

BOREHOLE DEPTH: 30.0 FT

SURFACE ELEVATION: 466.00 FT

Cave in Depth (ft)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 1 of 2

A E

C O

M S

O

IL

R O

C K

A E

C O

M -G

E O

T E

C H

_F T

B R

A G

G S

O F

(1

G

P J

A E

C O

M -G

E O

T E

C H

_P R

O

JE

C T

-D E

S

IG

N .G

D T

/1

1/

R

E V

-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-4

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

1.0 - 30.0 ft: Moist, medium dense, orangish brown, POORLY GRADED SAND WITH SILT(continued)

21.5 ft: changes to contains 4" dark brown layer

21.8 ft: changes to contains 2" layer of loose, gray, fine to coarse, Poorly Graded Sand (SP)

26.0 ft: changes to medium dense

27.0 ft: changes to contains 6" light orangish brown layer

Boring completed at 30.0 FT on 4/15/2021 at

10:00 HOURS.

Boring backfilled with spoils/ bentonite-grout at the end of the day.

Since mud rotary methods were used, groundwater measuements were not obtained.

SP-

SM

S-11

S-12

S-13

S-14

S-15

19.5

(42%)

(42%)

(46%)

(50%)

(46%)

4- 3- 4- 4 (N=7)

3- 3- 4- 4 (N=7)

3- 5- 5- 6 (N=10)

6- 8- 9- 9 (N=17)

5- 8- 8- 9 (N=16)

AECOM TECHNICAL SERVICES, INC.

PROJECT: SOF Operations Annex Facility PROJECT LOCATION: Fort Bragg, NC

PROJECT NUMBER: 60625564

RC = Rock Core

B = Bulk Sample

T = Shelby Tube SampleG = Geoprobe

S = Split Spoon Sample

12420 Milestone Center Drive, Suite 150 Germantown, MD 20876 Phone: 301.820.3000 Fax: 301.820.3009

SHEET 2 of 2

A E

C O

M S

O

IL

R O

C K

A E

C O

M -G

E O

T E

C H

_F T

B R

A G

G S

O F

(1

G

P J

A E

C O

M -G

E O

T E

C H

_P R

O

JE

C T

-D E

S

IG

N .G

D T

/1

1/

R

E V

-0

SC = Sonic CorePS = Piston Sample

P = Pitcher Sample

H = Hand Auger Sample

DESCRIPTION

Log of Boring B-4

U S

C S

N U

M B

E R

SAMPLES

Li qu id L im it

P la st ic

L im it

P oc ke t P en ts f)

D E

P T

H

F T

G R

A P

H

IC

T Y

P E

T or va ne ts f)

REMARKS

AND TESTS

M oi st ur e C on te nt

E

LE

V

F T

R E

C

IN

BLOWS

S T

R A

T

0.0 - 0.1 ft: TOPSOIL

0.1 - 1.5 ft: (FILL) Moist, very loose, dark brown, Poorly Graded Sand

1.5 - 7.5 ft: Moist, medium dense, reddish brown, POORLY GRADED SAND WITH SILT

7.5 - 10.0 ft: Moist, medium dense, orangish brown, SILTY SAND

10.0 - 18.0 ft: Moist, medium dense, tan to light brown, POORLY GRADED SAND

12.0 ft: changes to loose, orangish brown

15.3 ft: changes to contains 7" layer of orangish brown, Silty Sand (SM)

18.0 - 22.0 ft: Moist, loose, light orangish brown, POORLY GRADED SAND WITH SILT

19.5 ft: changes to contains 6" layer of

SP

SP-

SM

SM

SP

SP-

SM

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-…