P1514 Shoot House - Geotechnical Report.pdf

GEOTECHNICAL

INVESTIGATION

REPORT

P-1514 Shoot House

MCB Camp Lejeune, Stone Bay North Carolina prepared for Clark Nexsen

Virginia Beach, VA

February 27, 2023 Revised July 3, 2023

2712 Southern Boulevard, Suite 101

Virginia Beach, VA 23452

757-463-3200 www.geronline.com

February 27, 2023

Revised July 3, 2023

Clark Nexsen 4525 Main St

Suite 1400

Virginia Beach, VA 23462

Attention: Ms. Dana Cook

Subject: Report of Geotechnical Services P-1514 Shoot House MCB Camp Lejeune, Stone Bay, North Carolina

GER Project No. 110-8071

GeoEnvironmental Resources, Inc. is pleased to present this report of geotechnical exploration for the above referenced project. Our services were performed in accordance with our proposal P22-110-7723 dated 6 May 2022.

We appreciate the opportunity to serve as your geotechnical consultant on this project and trust that you will contact us at your convenience with any questions concerning this report or the project in general.

Sincerely, eo nvironmental esources, Inc.

J. Andrew Blythe, E.I.T.

Geotechnical Engineer

Scott A. Barnhill, P.E.

Executive Vice President

C O

M M

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N

WEALTH OF V

IR

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IN

IA

P R

O

FESSIONAL ENGIN

E E

R

SCOTT A. BARNHILL

Lic. No. 012520

EXECUTIVE SUMMARY

Subsurface conditions for the Shoot House were explored by 4 Standard Penetration Test (SPT) soil borings to a depth of about 12 feet below the existing ground surface, 1 SPT soil boring to a depth of about 20 feet below the existing ground surface, 2 SPT soil borings to a depth of about 75 feet below the existing ground surface, one temporary monitoring well to a depth of about 20 feet below the existing ground surface, one cone penetration test (CPTu) sounding and one seismic cone penetration test (SCPTu) sounding to a depth of 59 feet below the existing ground surface where they both terminated due to refusal. Geotechnical laboratory analysis of samples included tests for natural moisture content, sieve analysis, plasticity, moisture-density relationship, CBR, and consolidation. Chemical laboratory analysis of two composite soil samples included tests for TPH-DRO, TPH-GRO, TCLP (VOCs, SVOCs, PCBs, organochlorine pesticides, herbicides, and metals), reactivity, ignitibility, water content, pH, sulfides, chlorides, soluble sulfates, oxidation-reduction potential, and electrical resistivity. Chemical laboratory analyses for TPH-DRO & GRO, TAL metals, TCL VOCs, and TCL SVOCs was also conducted on one composite groundwater sample.

The general soil profile is interpreted from the soil borings and is composed of 1 layer consisting of uncontrolled

FILL along with 3 native stratigraphic layers. These layers include:

Stratum A – Uncontrolled FILL material: silty SAND with brick and concrete fragments to a depth of about 1 foot.

Stratum 1 – very loose to medium dense, clayey SAND, silty SAND, silty SAND with clay, clayey SAND with silt, and poorly-graded SAND with silt to a depth of about 6 to 9 feet.

Stratum 2 – Very soft to stiff, lean CLAY with sand and silt, fat to lean CLAY with silt and sand, sandy lean CLAY, fat CLAY with sand and silt, fat CLAY with sand, and lean SILT with sand to depths ranging from the termination depth of exploration of about 12 to 20 feet at the shallow borings and to a depth of about 27 feet at the deep borings.

Stratum 3 – Very loose to very dense, clayey SAND, silty SAND, silty SAND with clay, clayey SAND with silt, poorly-graded SAND with silt, poorly-graded SAND, and poorly-graded GRAVEL to the termination depth of exploration of about 75 feet.

The building can be supported using shallow foundations. The allowable soil bearing pressure is 2000 psf. The use of a turned down slab is also an option.

Conventional ground supported concrete floor slabs can be used for the project.

Estimated total settlements of properly supported footings are expected to be tolerable for column loads of 120 kips, wall loads of 4 klf, and fill heights of up to 1 foot.

The upper soils excavated from the site are not expected to be suitable for reuse as structural fill and backfill on the project based on field and laboratory tests. It should also be noted that due to minor contaminant detection in selected soil samples, construction activities at the site may require guidance provided by the NAVFAC

Environmental Affairs Department (EAD). Potential disruptive excavation of anomalies that include USTs should be avoided based on geophysical testing.

Seismic Site Class D is expected to be appropriate for the project site based on this exploration and our past experience.

The laboratory CBR test values on the compacted sandy soil samples from the upper 1 to 3 feet were 6.9, 8.8, 10.9, and 11.0. A design CBR of 6 is recommended which is 2/3 the average of the CBR test results.

PAGE

PURPOSE OF EXPLORATION 1

PROJECT INFORMATION 1

SITE DESCRIPTION 1

SITE GEOLOGY 1

EXPLORATION PROGRAM 2

EXPLORATION RESULTS 3

Soil Stratigraphy 3

Soil Survey 3

Test Pits 4

Groundwater 4

Surface Materials 4

Photoionization Detection Screening 4

Historical Data Review 4

Geophysical Test Results 4

Geotechnical Laboratory Testing 5

Chemical Laboratory Testing 5

SUBSURFACE EVALUATION 7

RECOMMENDATIONS 7

Shallow Foundations 7

Ground Slabs 8

Pavements 8

Earthwork 9

Fill and Backfill 9

Seismic Properties 10

Stormwater Management BMPs 10

Underground Utilities

LIMITATIONS 11

APPENDICES

APPENDIX A - Drawings

APPENDIX B - Field Test Data

APPENDIX C - Laboratory Test Data

APPENDIX D – Procedures

APPENDIX E – Calculations

P-1514 Shoot House, MCB Camp Lejeune Revised July 3, 2023 Project 110-8071 Page 1

Purpose of Exploration

The purpose of this study was to collect geotechnical data for the planned Shoot House at the project site and to develop conceptual building foundation and site development design in support of the execution of this Design-Bid- Build (DBB) project.

Project Information

The project includes the construction of an 11,100 square foot (SF) single story shoot house facility south of the existing facility. The new building will likely utilize structural steel framing, reinforced CMU or concrete walls, reinforced concrete floors, ballistic walls, and a projectile absorption space system. In addition, an after action review/briefing facility will be constructed adjacent to the shoot house. This facility will consist of interior and exterior CMU walls with structural steel framing, reinforced masonry walls, CMU veneer, and reinforced concrete foundation and floors. The proposed supporting facilities will include paving, sidewalks, storm water management, clearing and grubbing, earthwork, fill, grading, landscaping, and underground utilities.

The project will include the demolition of building RR249 and removal of vegetation and utilities within the site to accommodate the new facilities.

The freestanding wall loading is anticipated not to exceed 4 klf. Column loading is anticipated not to exceed 120 kips. Floor loading is anticipated not to exceed 225 psf. Fill used to increase existing grades at the site is not anticipated to exceed 1 ft.

Site Description

The project site is located at the Marine Corps Base Camp Lejeune (MCBCL) in Holly Ridge, North Carolina within the Expeditionary Operations Training Group (EOTG) area at Stone Bay. Specifically, it is located northeast of the intersection of Booker T Washington Boulevard and Dr. G W Carver Street. Building RR249 occupies a portion of the northern area of the site while the surrounding vicinity consists mostly of an open field with a few trees and a fence along the outer edges along with a stormwater basin.

The approximate project limits are shown on Drawing 1 in Appendix A.

Based on previously existing data and historical satellite imagery, previously demolished buildings existed within the immediate vicinity of test pit location TP-4. FILL material is likely in much of project area as a remnant of former development and demolition activity, especially on the west side of the project.

Site Geology

The project site lies within North Carolina’s Atlantic Coastal Plain physiographic province. The Coastal Plain is characterized by an eastward thickening wedge of marine, estuarine and fluvial sediments that were deposited in a series of marine transgressive-regressive cycles, or high and low stands of sea level, during the Holocene to

Miocene epochs of the late Cenozoic era.

According to the 1985 Geologic Map of North Carolina, the upper geologic units at the site are composed of unconsolidated Holocene and Upper Pleistocene age deposits of undivided members. Older underlying units include consolidated Tertiary deposits of the River Bend Formation, undivided, described as limestone, calcarenite overlain by and intercalated with indurated sandy, molluscan-mold limestone.

Project 110-8071 Page 2

Exploration Program

The subsurface exploration program consisted of the following sampling and testing at the approximate locations shown on Drawings 2A and 2B in Appendix A:

❑ Performing 4 Standard Penetration Test (SPT) soil borings to a depth of 12 feet below the existing ground surface, 1 SPT to a depth of 20 feet below the existing ground surface, and 2 SPTs to a depth of 75 feet below the existing ground surface.

❑ Collecting 2 composite soil samples from the upper 1 to 4 feet for laboratory chemical analysis.

❑ Collecting 1 composite water sample from the temporary monitoring well for laboratory chemical analysis.

❑ Performing 1 Seismic Cone Penetration Test (SCPTu) sounding and 1 Cone Penetration Test (CPTu) sounding to a depth of 59 feet below the existing ground surface at which they both terminated due to refusal.

❑ Performing pore pressure dissipation in representative soft clay/silt strata for estimation of the horizontal conductivity ch.

❑ Performing 5 test pits to depths of 9 to 10½ feet.

❑ Performing geotechnical laboratory testing that included natural moisture content, sieve analysis, plasticity, moisture-density relationship, CBR, and consolidation tests on selected representative samples recovered from the soil borings.

❑ Performing chemical laboratory testing that included TCLP (VOCs, SVOCs, organochlorine pesticides, herbicides, PCBs, and metals), TPH-DRO & GRO, ignitability, reactivity, water content, pH, soluble sulfates, chlorides, electrical resistivity, redox potential, and sulfides on two composite soil samples.

❑ Performing chemical laboratory testing that included TPH-DRO, TPH-GRO, TAL Metals, TCL VOCs, and TCL

SVOCs on one composite groundwater sample.

The soil borings were performed on November 9th and 10th, 2022. SPT borings were advanced by a CME 45 ATV mounted drill rig using boreholes drilled by mud rotary techniques, except when installing the temporary monitoring well in which hollow stem augers were used. Standard penetration test sampling was conducted in these borings at discreet intervals in general accordance with ASTM D1586. An automatic hammer was used to drive the sampler.

Small, disturbed samples obtained during the test were visually classified in general accordance with ASTM D2487 and selected representative samples were saved for laboratory testing.

The test pits were performed on December 20th, 2022. Excavation sidewalls and excavation material was visually classified and inspected anomalies (fill material, debris, abandoned utility lines, etc.) in the area.

Observation of water table depth was made in the open boreholes during and immediately following completion of drilling. Stabilized groundwater tables were recorded at location B-7 both 24 hours and 48 hours after well installation. All boreholes were backfilled with a bentonite grout mix upon completion of the testing, groundwater sampling, and water level measurements.

A geophysical survey to delineate buried structure and debris was conducted by Pyramid Geophysics on November

17, 2022.

The approximate test locations are shown in Drawings 2A and 2B in Appendix A. Field test results are provided in

Appendix B. Laboratory test results are provided in Appendix C. Exploration and sampling procedures are provided in Appendix D. Calculations are provided in Appendix E.

Project 110-8071 Page 3

Exploration Results

The subsurface conditions encountered at the boring locations are shown on the test borings records in the report in Appendix B.

The test boring records represent our interpretation of the subsurface conditions based on visual examination of field samples, excavated material, and observation of the excavation side wall materials. Field samples were obtained for laboratory classification testing on selected samples. The lines designating the interface between various strata on the boring records represent the approximate interface location. In addition, the transition between strata may be gradual. Water levels shown on the boring records without temporary monitoring wells only represent the observations at the time of the field exploration. Ground elevations shown on the boring and test pit logs range from about 22½ to 29 feet and are based on estimations from the topographic map provided in Appendix

A.

Soil Stratigraphy The subsurface soil conditions encountered in the borings were composed of uncontrolled FILL material and native soils. The estimated profiles are developed based on the findings at the specific test locations, and variations between the profiles and actual subsurface conditions should be expected.

STRATUM A consists of Uncontrolled FILL material composed of medium dense, silty SAND, (SM) with brick and concrete fragments. Stratum A was encountered at test location B-6 to a depth of about 1 foot below the existing ground surface (BGS) and also in test pits TP-1, TP-3, TP-4, and TP-5. The N-value in Stratum A was 12 bpf.

STRATUM 1 is composed of very loose to medium dense, fine grained, silty SAND, silty SAND with clay, clayey SAND, clayey SAND with silt, and poorly-graded SAND with silt (SM, SM-SC, SC, SC-SM, & SP-SM). Stratum 1 was encountered at all testing locations to depths ranging from approximately 6 to 9 feet BGS. It was encountered beneath the existing surficial soil at most locations, at the ground surface at location B-7, and beneath Stratum A at location B-6. N-values in Stratum 1 ranged from 4 to 19 bpf, with an average of 9 bpf. CPT point resistance (qt) ranged from about 11 to 129 tsf.

STRATUM 2 is composed of very soft to stiff, fat to lean CLAY with sand and silt, lean CLAY with sand and silt, sandy lean CLAY, fat CLAY with sand, lean CLAY, lean SILT with sand, fat CLAY with sand and silt, and lean SILT with sand (CH-CL, CL, CH, & ML). Stratum 2 was encountered beneath Stratum 1 at all testing locations to depths ranging from the termination depth of exploration of the shallow borings at approximately 12 and 20 feet BGS to a depth of approximately 27 feet BGS at the deep borings. N-values in Stratum 2 ranged from 1 to 10 bpf, with an average of 4 bpf. CPT point resistance (qt) ranged from about 2 to 47 tsf.

STRATUM 3 is composed of very loose to very dense, clayey SAND, silty SAND, poorly-graded SAND with silt, clayey SAND with silt, silty SAND with clay, poorly-graded SAND, and poorly-graded GRAVEL (SC, SM, SP-SM, SC-

SM, SM-SC, SP, & GP). Stratum 3 was encountered beneath Stratum 2 only at the deep testing locations to the termination depth of exploration of approximately 75 feet BGS. N-values in Stratum 3 ranged from the weight of the hammer to spoon refusal which is defined as 50 blow over less than 6 inches, with an average of 41 bpf. CPT point resistance (qt) ranged from about 34 to 725 tsf.

Soil Survey According to the USDA NRCS web soil survey, the general project site consists of 3 mapped soil units – Baymeade fine sand, Baymeade-Urban land complex, and Marvyn loamy fine sand. Baymeade fine sand composes approximatley 22.5 percent of the site area, Baymeade-Urban land complex composes approximately 71.5 percent of the site area, and Marvyn loamy fine sand composes approximatley 6 percent of the site area. The web soil survey unit location and detailed description are included at the end of Appendix B.

Project 110-8071 Page 4

Test Pits Five test pits were excavated to depths ranging from about 9 to 10½ feet below the existing ground surface as part of the exploration. There was no evidence of groundwater intrusion or caving during the excavation of thes test pits. The test pits were used to confirm anomalies discovered during the Geophysical Investigation performed onsite and to evaluate the types of materials that may remain buried on site. During the exploration, Stratum A uncontrolled FILL material consisting of concrete and brick fragments were encountered at all test pit locations on the east side of the site (TP-3, TP-4, & TP-5) to depths ranging from about 1 to 3 feet. TP-5 also encountered abandoned metal pipes at a depth of about 1½ feet. The test pits on the west side of the project (TP-1 &TP-2) did not encounter concrete and brick fragments; but metal rebar was encountered at test location TP-1 at a depth of about 1 foot. Test Pit Records and Boring Logs are included in Appendix B.

Groundwater The groundwater table was encountered at depths ranging from about 17 to 18 feet below the existing ground surface at the time of drilling at locations across the entire project. Temporary monitoring well B-7 had a stabilized water table of approximately 13½ feet at both 24 and 48 hours after installation. The estimated seasonal high water table ranges from depths of about 10½ to 12 feet below the existing ground surface throughout the project site.

The water levels shown on the testing records without monitoring wells represent the conditions encountered at the time frame of the exploration using mud rotary drilling and do not necessarily represent the stabilized water depths or water conditions that will be encountered during construction. Fluctuation in the water levels may occur due to variations in precipitation, evaporation, construction activity, surface runoff, tides and other local factors.

Contractors should anticipate these variations in planning and scheduling the work.

Two constant-head, infiltration tests were conducted. INF-1 was conducted at a depth of 33 inches, and INF-2 was conducted at a depth of 36 inches. Infiltration rates of sandy soils were measured at 0.675 in/min for INF-1 and

0.427 in/min for INF-2.

Surface Materials Approximately 4 to 6 inches of surficial soils were encountered at the testing locations. The surficial soil material consisted generally of fine grained, silty SAND with trace organics. Test locations B-6 and B-7 did not contain any surficial soil; but contained fine grained silty SAND at the surface without the organic material encountered at the other testing locations. The thickness and composition of surface materials should be expected to vary across the project limits.

Photoionization Detection Screening

Each split-spoon sample was screened for petroleum related pollutants and solvent related volatile organic compounds (VOCs) immediately after recover in the field using a MiniRAE3000 photoionization detector. PID screening results ranged from approximately 0.0 ppm to 118.1 ppm throughout the project vicinity. Results are shown on the boring logs in Appendix B.

Historical Data Review Based on previously existing data provided for projects done in nearby areas, the subsurface conditions found in this report are similar to those found with previous explorations.

A small building formerly existed in the southwest portion of the project but was demolished sometime between

2008 and 2011, in which construction and clearing of the woodlands on the southeaster portion of the site appear to have taken place. Remnants of the formerly existing building in the southwestern portion of the site were encountered during test pit excavations.

Geophysical Test Results The EM and GPR surveys of the Shoot House property were successful in identifying buried metallic debris and structures across the site. A variety of buried anomalies were observed across the site. The anomalies included:

▪ Known buried utilities – included electric, water, and communication lines

Project 110-8071 Page 5

▪ A suspected utility/pipeline spanning across a large portion of the west survey area with multiple connections

▪ Suspected isolated buried pipe sections with no clear lateral connections

▪ Individual buried metallic objects

▪ Possible underground storage tanks (USTs)

▪ Zones of suspected buried metallic debris or former infrastructure/foundations

Two possible USTs were identified, both approximately 8 feet long by 4 feet wide along with a suspected utility pipeline. The location of the USTs, pipelines, and anomalies should be coordinated with planned excavations.

We understand that none of the anomalies lie within the building area, but may impact utilities or other site development.

Geotechnical Laboratory Testing Geotechnical laboratory testing was conducted on selected samples recovered from the soil borings. The geotechnical laboratory program included 20 natural moisture content tests (ASTM D2216), 20 Atterberg limits tests (ASTM D4318), 20 sieve analysis tests (ASTM D6913), 4 moisture-density relationship tests (ASTM D698), 4

CBR tests (ASTMD1183), and 3 consolidation tests (ASTM D2435).

Tables 1 and 2 provide a brief summary of laboratory test results. Complete Geotechnical laboratory test summaries and test results are provided in Appendix C.

Table 1 CBR Moisture-Density Relationship Test Summary

As shown in Table 1, above, existing sandy soils are present at moisture levels below optimum in regard to compaction characteristics.

A summary of consolidation test results is provided below. Characteristics of generally overconsolidated clays found at the site are shown.

Table 2 Consolidation Test Summary

Chemical Laboratory Testing Chemical testing of the two composite soil samples recovered from the upper 1 to 4 feet at locations B-2 and B-6 included TCLP (VOCs, SVOCs, organochlorine pesticides, herbicides, PCBs, and metals), TPH-DRO & GRO, reactivity, ignitibility, water content, pH, soluble sulfates, chlorides, electrical resistivity, redox potential, and sulfides. Location B-2 tested positive for Diesel Range organics with a result of 18 mg/Kg, Lead with a result of 0.53 mg/L, Cyanide

Boring Depth USCS mc (%) Maximum Dry Density

(pcf)

Optimum Moisture

Content (%)

B-1 1'-3' SP-SM 6.2 108 12.0

B-2 1'-3' SP-SM 3.3 107.8 11.7

B-3 1'-3' SP-SM 3.8 107.7 12.3

B-4 1'-3' SP 3.5 106.7 13.3

Boring Depth USCS Cc Cs Cr P'c

(ksf)

Su

(ksf)

OCR

Constrained

Modulus (ksf)

Ko

(oc)

B-5 22'-24' CL 0.227 0.031 0.023 4.1 0.87 2.1 401 0.78

B-6 12'-14' CH 0.369 0.054 0.017 4 0.79 2.7 384 0.95

B-6 16'-18' CH 0.399 0.064 0.027 8.5 1.54 4.1 304 1.27

Project 110-8071 Page 6 with a result of 7.9 mg/Kg, and Sulfide with a result of 110 mg/Kg. Location B-6 tested positive for Lead with a result of 0.013 mg/L and Cyanide with a result of 0.27 mg/Kg. Both locations had Flashpoint values greater than

200 Degrees Fahrenheit.

Oxidation Reduction Potential results ranged from 150 to 160 millivolts. pH values ranged from 7.01 to 7.15.

Resistivity values ranged from 29,670 to 32,840 ohm-cm.

A summary of the contaminant and corrosion test results are provided in Table 3.

Table 3 Soil Contaminant and Corrosion Test Summary

Chemical Test B-2 B-6

TPH-DRO 18 mg/Kg <Reporting Limits TPH-GRO <Reporting Limits <Reporting Limits TCLP VOCs <Reporting Limits <Reporting Limits TCLP SVOCs <Reporting Limits <Reporting Limits TCLP PCBs <Reporting Limits <Reporting Limits TCLP Organochlorine Pesticides <Reporting Limits <Reporting Limits TCLP Herbicides <Reporting Limits <Reporting Limits TCLP Metals - Lead 0.53 mg/L 0.013 mg/L Ignitability >200 F˚ >200 F˚ pH 7.15 7.01 Sulfides 110 mg/Kg <Reporting Limits Chlorides <Reporting Limits <Reporting Limits Soluble Sulfates <Reporting Limits <Reporting Limits Oxidation-Reduction Potential 150 mv 160 mv Electrical Resistivity 29,670 ohm-cm 32,840 ohm-cm

It should be noted that due to minor contaminant detection in selected soil samples, construction activities at the site may require guidance provided by the NAVFAC Environmental Affairs Department (EAD).

The Numerical Soil Corrosivity Scale developed by the American Water Works Association (AWWA) was referenced to evaluate the corrosivity of the composite samples at test boring locations B-2 and B-6. The scale runs on a point system in which a higher value of points indicates a higher corrosivity potential applicable to cast iron alloys. When the total points of a soil on the scale are 10 or higher, corrosive protection measures are recommended for cast iron alloys. According to the Numerical Soil Corrosivity Scale, the upper 4 feet at test boring B-2 has a value of 3.5 on the AWWA scale and the upper 4 feet at test boring B-6 has a value of 0 on the AWWA scale. Given these results, corrosive protective measures are not likely to be required.

Chemical testing of the composite water sample recovered from the temporary monitoring well at location B-7 included TPH-DRO & GRO, TAL Metals, TCL VOCs, and TCL SVOCs. Location B-7 tested positive for Carbon disulfide with a result of 3.2 ug/L, Dibenz(a,h)anthracene with a result of 5.3 ug/L, Aluminum with a result of 43 mg/L, Arsenic with a result of 0.014 mg/L, Barium with a result of 0.12 mg/L, Beryllium with a result of 0.0013 mg/L, Boron with a result of 0.046 mg/L, Calcium with a result of 7.3 mg/L, Chromium with a result of 0.10 mg/L, Cobalt with a result of 0.018 mg/L, Copper with a result of 0.022 mg/L, Iron with a result of 40 mg/L, Lead with a result of 0.042 mg/L, Magnesium with a result of 5.0 mg/L, Manganese with a result of 0.21 mg/L, Molybdenum with a result of 0.010 mg/L, Nickel with a result of 0.029 mg/L, Potassium with a result of 6.8 mg/L, Sodium with a result of 6.3 mg/L, Vanadium with a result of 0.073 mg/L, and Zinc with a result of 0.16 mg/L.

Project 110-8071 Page 7

Table 4 Water Contaminant Test Summary

Analyte Result RL MDL Unit

Carbon disulfide 3.2 1.0 0.50 µg/L Dibenz(a,h)anthracene 5.3 17 4.7 µg/L Aluminum 43 0.20 0.051 mg/L Arsenic 0.014 0.01 0.003 mg/L Barium 0.12 0.01 0.003 mg/L Beryllium 0.0013 0.003 0.001 mg/L Boron 0.046 0.1 0.022 mg/L Calcium 7.3 0.5 0.084 mg/L Chromium 0.10 0.01 0.005 mg/L Cobalt 0.018 0.01 0.003 mg/L Copper 0.022 0.02 0.017 mg/L Iron 40 0.2 0.075 mg/L Lead 0.042 0.01 0.002 mg/L Magnesium 5.0 0.5 0.12 mg/L Manganese 0.21 0.01 0.003 mg/L Molybdenum 0.01 0.1 0.004 mg/L Nickel 0.029 0.006 0.003 mg/L Potassium 6.8 1.0 0.34 mg/L Sodium 6.3 2.0 0.92 mg/L Vanadium 0.073 0.02 0.007 mg/L Zinc 0.16 0.02 0.008 mg/L

Complete chemical laboratory test results are provided in Appendix C.

Subsurface Evaluation

We have conducted an evaluation of the project information, site and subsurface conditions described in the preceding sections with regard to supporting the Shoot House and anticipated site development.

It is anticipated that under the proposed maximum structural loads, the proposed building can be supported using a conventional shallow foundation system. The anticipated allowable or design soil bearing pressure is 2000 psf.

The location of the USTs and anomalies should be coordinated with planned excavations. Uncontrolled FILL was encountered at depths ranging from about 1 to 3 feet BGS based on borings and test pits.

Estimated total settlements of properly supported footings under the design column loads are expected to be within tolerable limits for combined loading that includes column loads of up to 120 kips, wall loads of up to 4 klf and fill depth of 1 foot. Settlement calculations are provided in Appendix E.

Recommendations

The following recommendations are provided based on the subsurface data obtained from the site and our engineering analysis of subsurface conditions and project information furnished to us.

Project 110-8071 Page 8

Shallow Foundations ❑ The use of shallow spread footings bearing on approved existing soils or on properly constructed select fill material may be used for supporting the structure. The allowable design soil bearing pressure is 2000 psf. The use of a turned down slab is also an option.

❑ Footings should bear at least 18 inches below final building grades for lateral bearing capacity considerations and for protective embedment.

❑ Minimum footing widths are 20 inches for continuous strip footings and 30 inches for individual column footings for ease of construction and to avoid a punching failure of the supporting soils. Footing widths should be increased proportionately for the structural loads and design bearing pressure.

❑ The edges of turned down slabs can be a nominal width of 12 inches or more as required.

❑ Total settlement of properly supported footings are expected to be within tolerable limits for combined maximum column loads of up to 120 kips, wall loads of 4 klf, and fill depths of 1 ft. Total settlement due to consolidation is estimated to be on the order of ½ inch for combined loading conditions including building and fill loads.

❑ Differential settlement on the order of one half of the estimated total settlement can be expected based on site conditions encountered during the exploration.

❑ Friction factor, tan δ = 0.3, is appropriate for concrete surfaces that interface with the subsurface soils, as listed in Chapter 3, Table 1 of NAVFAC DM7.2.

❑ Prior to installing reinforcing steel and concrete, footing subgrades should be composed of relatively firm, dry suitable soils free of debris, organics, and loose material. This should be verified by a field inspector during construction. Actual soil conditions should be compared to those described in this report upon which design criteria have been based.

❑ If unsuitable subgrade materials are encountered at the footing locations, the Engineer should be notified. The likely remediation measure for unsuitable materials would be to undercut the unsuitable materials to reach firm suitable soil and replacement with #57 crushed stone backfill to the design footing bearing elevation.

❑ Expansive subgrade soils exhibiting shrink/swell are not anticipated at the site.

❑ If the soil conditions encountered are different from those described in this report, the geotechnical engineer should be contacted. Soft, wet materials and organic soils present beneath the foundation subgrade and debris fill deemed unsuitable should be removed and replaced under direction of the Engineer.

Ground Slabs ❑ Conventional ground supported concrete floor slabs appear appropriate for the proposed building. Floating slabs should generally be jointed at column lines and along load bearing walls so that foundations and the slab can settle differentially without damage.

❑ Subgrade modulus for the building slabs will be based in part on the quality of the imported fill material. For good quality local compacted fill over the existing subgrade soils, a subgrade modulus of 150 pci may be assumed.

❑ A minimum 4 in thick layer of porous gravel or clean sand fill should be used directly beneath the slabs for lateral drainage of moisture. If sand is chosen, it should conform to ASTM C 33 concrete fine aggregate or equivalent. The porous fill layer should be covered with an impermeable membrane sheeting to prevent clogging during concrete placement.

Pavements ❑ The laboratory CBR test values on the compacted samples from the upper 1 to 3 feet was

Project 110-8071 Page 9

6.9, 8.8, 10.9, and 11.0. A design CBR of 6 is recommended which is 2/3 the average of the CBR test results.

❑ The following pavement sections may be appropriate for the project:

Standard Duty Asphalt Pavement (Roadway and Parking):

• 3 inches SM Surface Course

• 8 inches aggregate base course

• 12 inches firm natural subgrade or compacted structural fill

Light Duty Concrete Pavement (Walkways):

• 4 inches Portland Cement Concrete (PCC)

• 6 inches aggregate base course

• 12 inches firm natural subgrade or compacted structural fill

Regarding the dumpster equipment pad locations as well as the aggregate surface area shown on drawing CS101 in Appendix A, we have assumed ADTs as: 20 vehicles per day (2-axle trucks) and 1 dumpster pull per day (3-axle truck) over a design life of 20 years and a design CBR of 6 (soil modulus of 300 pci).

The following minimum sections are recommended:

Unsurfaced Aggregate Entry Road:

• 5 inches aggregate base course

• Tensar NX-750 geogrid

• 12 inches firm natural subgrade or compacted structural fill

Heavy Duty Concrete Pavement (Service Areas):

• 6 inches Portland Cement Concrete (PCC)

• 8 inches aggregate base course

• 12 inches firm natural subgrade or compacted structural fill o Rigid PCC pavement should attain a minimum 28-day flexural strength of 650 psi and use reinforcing steel only where required by UFC or past experience.

o All rigid pavement joints should use doweled construction spaced at 15 to 20 feet as appropriate for its thickness.

o Aggregate base course should conform to NCDOT gradation ABC and should consist of crushed quarry stone or shell rock material. ABC should be compacted to 100 percent of ASTM D 1557.

o Unsurfaced roadways should be designed and maintained in accordance with applicable FHWA, UFC and/or

NCDOT guidance.

o Adequate drainage should be maintained at paved areas at all times.

Earthwork ❑ The ground surface in the building areas should be cleared, grubbed and stripped of all vegetation, topsoil, asphalt, concrete, and other debris to reach firm soils. This work should be performed during a period of dry weather to avoid excessive deterioration of the exposed subgrade. Positive surface drainage should be maintained at all times during construction to prevent water accumulation on the subgrade.

❑ Topsoil and unsuitable material should be removed horizontally to a nominal 5 feet beyond the outside of building lines.

❑ Existing underground utilities within the proposed building areas should be rerouted to outside of the new building footprints. Excavations should be backfilled with compacted select material as specified in this report.

Project 110-8071 Page 10

❑ We understand that none of the anomalies shown in the geophysical survey lie within the building area but may impact utilities or other site development. Such impacts should be remediated by removal of the anomaly and backfilled with compacted structural fill.

❑ The exposed subgrade soils in the building areas should be inspected by proofrolling and visual assessment to check for pockets of soft soils prior to filling and foundation and slab construction. Proofrolling should be conducted with a loaded dump truck or similar heavy rubber-tired construction equipment.

❑ The construction area should be graded to provide positive surface water runoff away from the construction activity and provide temporary ditches, swales, sump pits and other drainage features and equipment as needed to maintain dry and stable soil conditions.

❑ The contractor should be responsible for providing reasonable measures to provide drainage, protect the subgrade and implement appropriate work planning, sequencing and execution to minimize subgrade deterioration and to promote workable conditions. Measures and equipment to manage surface and subsurface water and to promote drying of the subgrade should be included in the contractor's bid.

❑ The subgrade may be susceptible to deterioration under loads from repeated construction traffic and the subgrade will become unsuitable for pavement support even during ideal weather conditions. This will be worse when construction occurs during wet weather. Thus, adequate support for pavements will be seasonal with the need for less subgrade stabilization if the subgrade is adequately protected from surface water and construction occurs in the drier months. It is inevitable that some subgrade deterioration will occur regardless of the time of season.

❑ Site stripping and grading should be observed by a field inspector. If unsuitable soil conditions are observed, they should be corrected by excavating and replacement with structural fill or improved by other methods that are acceptable to the Engineer.

Fill and Backfill

❑ Representative samples of each proposed fill material should be collected before filling operations begin and tested to determine maximum dry density, optimum moisture content, natural moisture content, gradation, plasticity, and CBR. These tests are needed for quality control during construction and to determine if the fill material is acceptable.

❑ Fill and backfill soil used in building and pavement areas should consist of non-plastic select material having a maximum of 25 percent fines by ASTM D 1140. Acceptable soil classifications by ASTM D 2487 include GW, GP, GM, SW, SP, SP-SM, and some SM soils. Upper soils excavated at the site are not expected to be suitable for use as fill soils.

❑ Potential disruptive excavations of anomalies should be avoided based on geophysical testing. Any anomalies within and up to 5 feet outside the building footprint should be removed in their entirety and backfilled with properly compacted fill soils.

❑ Unsuitable soils may be encountered. We recommend that the project budget include 200 cubic yards for disposal of unsuitable soils.

❑ Crushed stone can be used for backfilling beneath footings, grade beams, etc., and should consist of washed crushed stone conforming to gradation #57 by ASTM C 33 or VDOT specifications.

❑ Fill and backfill soils should be spread in thin, even layers not exceeding 8 inches loose thickness prior to compaction. Each layer of soil in building and pavement areas should be compacted to achieve no less than 95 percent of the laboratory maximum dry density as determined by ASTM D 1557, the standard Proctor.

❑ The moisture content of fill soils should be maintained within ±2 percentage points of the optimum moisture content determined from the laboratory Proctor density test. Fills should be free of debris and deleterious materials and have a maximum particle size diameter less than 2 inches.

Project 110-8071 Page 11

❑ The fill surface must be adequately maintained during fill construction. The fill surface should be compacted smooth and properly graded to improve surface runoff while construction is temporarily halted. Excavations to receive backfill should not be left open for extended periods.

❑ Where backfill is required in excavations that penetrate the groundwater table, an initial 6 to 12 in layer of #57 crushed stone should be used to serve as a stable base for compaction of subsequent lifts of soil fill.

Groundwater should be lowered below the crushed stone elevation by pumping prior to compacting the soil.

❑ Fill should not be placed on wet or frozen ground. Fill which becomes softened from excess moisture should be aerated and recompacted to acceptable levels, removed and replaced with new compacted fill, or as otherwise directed by the contracting officer’s representative.

Seismic Properties ❑ Based on the USGS seismic hazard mapping web site for ASCE 7-16, the following seismic site parameters appear to be appropriate for the project site (5% damping and 2% probability of exceedance in 50 years):

Site Class D

Peak Ground Acceleration 0.058

3 Spectral Response SMS 0.189

Spectral Response SM1 0.135

Spectral Response SDS 0.126 2 Spectral Response SD1 0.09

Site Coefficient Fa 1.6

Site Coefficient Fv 2.4

❑ ʋs(avg) = 1120 feet per second (fps) at testing location SCPTu-1 based on shear wave velocity readings taken in the upper 60 feet of soil. Although some soft clays were encountered in the borings that could classify as Site

Class E soft clays in accordance with ASCE 7-16, ʋs(avg) readings are likely more accurate for use in seismic site class determination, noting that the lowest reading indicated 650 fps – greater than the Site Class E upper bound of 600 fps.

❑ The site is located in an area having historically low seismic activity. The project site is not expected to be susceptible to earthquake induced slope failures. Also, the site is not located near any known active faults that could cause surface ruptures.

❑ Saturated, unconsolidated, loose sands that may be subject to liquefaction are not present in significant quantities at the site.

Stormwater Management BMPs ❑ Preliminary seasonal high water table elevations at the project site may range from about 10 to 12 feet below the existing ground surface, based on the initial groundwater depths measured in Field Testing Records in

Appendix B.

❑ Low Impact Design (LID) stormwater BMP systems should incorporate underdrains that outfall to daylight or connect to existing storm drains if systems are planned to reach into lower permeability clayey soils located within upper soils layers that were encountered in the borings at the site and may impact permeability.

Underground Utilities ❑ Most of the Stratum 1 soils above the groundwater table should provide satisfactory support of underground utilities as typically constructed for this type of project in this locality.

❑ According to AWWA C-105 and corrosion testing results, the site soils should not be considered corrosive to ferrous metals.

Project 110-8071 Page 12

❑ Dewatering considerations should be addressed for excavations greater than 10 feet below the existing ground surface. Estimated seasonal high groundwater tables of 10 to 12 feet below the existing ground surface may also be encountered at the time of construction and should be anticipated.

❑ Utilities that are installed at and below the groundwater table and/or in cohesive or extremely loose sandy soils should receive a minimum 6-inch bedding of gravel or crushed stone conforming to gradation #57 by

NCDOT or ASTM C 33. Bedding aggregate thickness should be adjusted as needed for the soil conditions encountered and dewatering methods employed.

❑ Loose sand soils may cave or slough if not supported. Utility excavations should be made in accordance with applicable OSHA regulations for Type C soil conditions.

Limitations

The analyses and recommendations provided are based in part on project information provided to us. They only apply to the specific project and site locations discussed in this report. If our understanding of the project is incorrect or if additional information is available, you should convey the correct or additional information to us and retain us to review our recommendations.

Regardless of the thoroughness of a geotechnical exploration, there is always a possibility that conditions between borings will be materially different from those at specific boring locations. In addition, soil conditions may become altered by construction activity and the passage of time. These possibilities should be considered by the designers and contractors.

APPENDIX A

GER

DRAWINGS

500 m 2000 ft

SITE

2712 Southern Boulevard, Suite 101 Virginia Beach, VA 23452

DRAWING NUMBERPROJECT NUMBER

VICINITY

MAP

PROJECT

LOCATION

SITE LOCATION PLAN

GERGeoEnvironmental Resources, Inc.

Consulting Engineers

Environmental Groundwater

Hazardous Materials Geotechnical

Industrial Hygiene

GeoEnvironmental Resources, Inc.

SOURCE:

USGS Topographic Map 2019 Sneads Ferry, NC

110-8071

P-1514 Shoot House MCB Camp Lejeune

Stone Bay Annex Jacksonville, NC

SITE

GeoEnvironmental Resources, Inc. B-5

CBR/MW

CS

B-10/CBR

B-12

B-13

B-14/CBR/CS

110-8071 2A

2712 Southern Boulevard, Suite 101 Virginia Beach, VA 23452

DRAWING NUMBERPROJECT NUMBER

TESTING LOCATION PLAN

GERGeoEnvironmental Resources, Inc.

Consulting Engineers

Environmental Groundwater

Hazardous Materials Geotechnical

Industrial Hygiene

0’ 100’ 200’

Graphic Scale 1”=100’

P1514 Shoot House MCB Camp Lejeune Stone Bay ANNEX

North Carolina

0’

0’

30’

75’

60’

150’

120’

300’

B-3

Source:

Google Maps 2022

CS

B-1

SCPTu-1

AS3534

PC/UD

PC

CS

CBR

CPT

CPT

CPT

CPT

SCPT

B-3/PC

B-1/PC

B-4/PC

B-2/PC/CS

B-5/PC

B-6/PC

B-7/PC

B-8/PC/CS

B-11/CBR

B-5

75’/SH

B-2

12’/CBR/CS(S)

B-6

75’/SH/CS(S)

SCPTu-1

59’/SW/PPD

B-4

12’/CBR

B-3

12’/CBR4958

49624961

Bulldog Road B-1

12’/CBR

CPTu-1

PPD

B-7

20’/MW/CS(W)

CBR: Bulk Sample SH: Shelby Tube CS(S): Composite Soil Sample CS(W): Composite Water Sample SW: Shear Wave Velocity Test PPD: Pore Pressure Dissipation

CS

TP-3

B-12

TP-5

TP-2

110-8071 2B

2712 Southern Boulevard, Suite 101 Virginia Beach, VA 23452

DRAWING NUMBERPROJECT NUMBER

TEST PIT LOCATION PLAN

GERGeoEnvironmental Resources, Inc.

Consulting Engineers

Environmental Groundwater

Hazardous Materials Geotechnical

Industrial Hygiene

0’ 100’ 200’

Graphic Scale 1”=100’

P1514 Shoot House MCB Camp Lejeune Stone Bay ANNEX

North Carolina

0’

0’

30’

75’

60’

150’

120’

300’

B-3

Source:

Google Maps 2022

CS

B-1

SCPTu-1

AS3534

PC/UD

PC

CS

CBR

CPT

CPT

CPT

CPT

SCPT

TP-4

B-1/PC

B-4/PC

B-2/PC/CS

TP-1

B-6/PC

B-7/PC

B-8/PC/CS

B-11/CBR

B-5

75’/SH

B-2

12’/CBR/CS(S)

B-6

75’/SH/CS(S)

SCPTu-1

59’/SW/PPD

B-4

12’/CBR

B-3

12’/CBR

49624961

Bulldog Road

B-1

12’/CBR

CPTu-1

PPD

B-7

20’/MW/CS(W)

CS

B-12

110-8071

2712 Southern Boulevard, Suite 101 Virginia Beach, VA 23452

DRAWING NUMBERPROJECT NUMBER

INFILTRATION TEST PIT

LOCATION PLAN

GERGeoEnvironmental Resources, Inc.

Consulting Engineers

Environmental Groundwater

Hazardous Materials Geotechnical

Industrial Hygiene

0’ 100’ 200’

Graphic Scale 1”=100’

P1514 Shoot House MCB Camp Lejeune Stone Bay ANNEX

North Carolina

0’

0’

30’

75’

60’

150’

120’

300’

B-3

Source:

Google Maps 2022

CS

B-1

SCPTu-1

AS3534

PC/UD

PC

CS

CBR

CPT

CPT

CPT

CPT

SCPT

B-1/PC

B-4/PC

B-2/PC/CS

B-6/PC

B-7/PC

B-8/PC/CS

B-11/CBR

B-5

75’/SH

B-2

12’/CBR/CS(S)

B-6

75’/SH/CS(S)

SCPTu-1

59’/SW/PPD

B-4

12’/CBR

B-3

12’/CBR

49624961

Bulldog Road

B-1

12’/CBR

CPTu-1

PPD

B-7

20’/MW/CS(W)

2C

-50

-40

-30

-20

-10

-50

-40

-30

-20

-10

B-1

B-2

B-3

B-4

B-5

B-6

B-7

Borehole Number

Topsoil SM, Silty Sand SC, Clayey Sand High to moderate plasticity clay

CL, Low Plasticity Clay Silty Sand to clayey sand Slightly silty, poorly graded sand USCS Clayey Sand

CH, High Plasticity Clay GP, Poorly-graded Gravel Fill ML, Low Plasticity Silt

SP, Poorly-graded Sand

Lithology Graphics

Site Map Scale 1 inch equals 155 feet

DRAWING NUMBER

SPT Blows

PROJECT NUMBER

P-1514 Shoot House Marine Corps Base Camp Lejeune, NC

Explanation

E

LE

V A

T

IO

N fe et

) B-1

CONSULTING ENGINEERS

110-8071

Borehole Lithology

Vertical Exaggeration: 2x

Water Level Reading after drilling.

Horizontal Scale (feet)

Water Level Reading at time of drilling.

DISTANCE ALONG PROFILE (feet)

G E

O T

E C

H N

IC

A

L P

R O

F

IL

E

E

LE

V A

T

IO

N

P -1

4.

G P

J G

E R

.G D

T

/5 /2

0 41

3A

TP-1

TP-2

TP-3

TP-4 TP-5

Borehole Number

Topsoil SM, Silty Sand High to moderate plasticity clay Silty Sand to clayey sand

Very Clayey Sand CL, Low Plasticity Clay USCS Clayey Sand

Lithology Graphics

Site Map Scale 1 inch equals 220 feet

DRAWING NUMBER

SPT Blows

PROJECT NUMBER

P-1514 Shoot House Test Pits Camp Lejeune, NC

Explanation

E

LE

V A

T

IO

N fe et

) TP-1

CONSULTING ENGINEERS

110-8071

Borehole Lithology

Vertical Exaggeration: 14x

Water Level Reading after drilling.

Horizontal Scale (feet)

Water Level Reading at time of drilling.

DISTANCE ALONG PROFILE (feet)

G E

O T

E C

H N

IC

A

L P

R O

F

IL

E

E

LE

V A

T

IO

N

S H

O O

T H

O U

S E

T E

S T

P

IT

S .G

P J

G E

R .G

D T

/5

/2

0 59

3B

1993 1998

2003 2006

2008 2011

2014 2017

12/27/22, 12:32 PM U.S. Seismic Design Maps https://www.seismicmaps.org 1/3

P-1514 Shoot House Latitude, Longitude: 34.58871, -77.44180

Date 12/27/2022, 12:32:42 PM

Design Code Reference Document ASCE7-16

Risk Category II

Site Class D - Default (See Section 11.4.3)

Type Value Description SS 0.118 MCER ground motion. (for 0.2 second period)

S1 0.056 MCER ground motion. (for 1.0s period)

SMS 0.189 Site-modified spectral acceleration value

SM1 0.135 Site-modified spectral acceleration value

SDS 0.126 Numeric seismic design value at 0.2 second SA

SD1 0.09 Numeric seismic design value at 1.0 second SA

Type Value Description SDC B Seismic design category https://www.seismicmaps.org 2/3

Type Value Description Fa 1.6 Site amplification factor at 0.2 second

Fv 2.4 Site amplification factor at 1.0 second

PGA 0.058 MCEG peak ground acceleration

FPGA 1.6 Site amplification factor at PGA

PGAM 0.092 Site modified peak ground acceleration

TL 8 Long-period transition period in seconds

SsRT 0.118 Probabilistic risk-targeted ground motion. (0.2 second)

SsUH 0.133 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration

SsD 1.5 Factored deterministic acceleration value. (0.2 second)

S1RT 0.056 Probabilistic risk-targeted ground motion. (1.0 second)

S1UH 0.064 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration.

S1D 0.6 Factored deterministic acceleration value. (1.0 second)

PGAd 0.5 Factored deterministic acceleration value. (Peak Ground Acceleration)

PGAUH 0.058 Uniform-hazard (2% probability of exceedance in 50 years) Peak Ground Acceleration

CRS 0.891 Mapped value of the risk coefficient at short periods

CR1 0.876 Mapped value of the risk coefficient at a period of 1 s

CV 0.7 Vertical coefficient https://www.seismicmaps.org 3/3

DISCLAIMER

While the information presented on this website is believed to be correct, SEAOC /OSHPD and its sponsors and contributors assume no responsibility or liability for its accuracy. The material presented in this web application should not be used or relied upon for any specific application without competent examination and verification of its accuracy, suitability and applicability by engineers or other licensed professionals. SEAOC / OSHPD do not intend that the use of this information replace the sound judgment of such competent professionals, having experience and knowledge in the field of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the results of the seismic data provided by this website. Users of the information from this website assume all liability arising from such use. Use of the output of this website does not imply approval by the governing building code bodies responsible for building code approval and interpretation for the building site described by latitude/longitude location in the search results of this website.

Soil Map—Onslow County, North Carolina (P-1514 Shoot House)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

1/2/2023

276020 276040 276060 276080 276100 276120 276140 276160 276180 276200 276220 276240

276000 276020 276040 276060 276080 276100 276120 276140 276160 276180 276200 276220 276240

34° 35' 21'' N

6'

2' ' W

34° 35' 21'' N

6'

2' ' W

34° 35' 16'' N

6'

2' ' W

34° 35' 16'' N

6'

2' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 50 100 200 300

Feet 0 15 30 60 90

Meters Map Scale: 1:1,130 if printed on A…