P1556_FINAL_GEOTECH REPORT_TEXT.pdf

Contract No. N40085-22-D-0043 Task Order No. N4008523F5964 eProjects Work Order No. 1760523

FY24 MILCON Project P-1556 10th Marines Maintenance & Operations Complex

Marine Corps Base, Camp Lejeune, Jacksonville, NC

Geotechnical Engineering Report

December 18, 2023

Prepared for: Naval Facilities Engineering Command (NAVFAC) Mid-Atlantic

Prepared by: AECOM

AECOM Project Number: 60713349

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1 INTRODUCTION AND SCOPE OF WORK ..................................................................... 1-1

2 EXISTING SITE CONDITIONS AND PROPOSED CONSTRUCTION ........................... 2-1

2.1 Field Maintenance Shop [A1] .................................................................................................. 2-1

2.2 Humidity Controlled Warehouse [A2] ...................................................................................... 2-1

2.3 NMESIS Weather Shelters [A3] .............................................................................................. 2-2

2.4 Artillery Weather Shelter [A4] .................................................................................................. 2-2

2.5 Addition to Building 1445 Communications and Electronics Shop [B1] ................................ 2-2

2.6 Addition to HP500 Armory [C1] ............................................................................................... 2-3

2.7 Addition to Building 1450 Automotive Maintenance Shop [D1] ............................................. 2-3

2.8 Hazards and Flammable Storage Shelter [D2] ...................................................................... 2-4

2.9 Wash Rack Extension ............................................................................................................. 2-4

2.10 POV Parking Lot ...................................................................................................................... 2-4

3 HISTORICAL IMAGERY AND DOCUMENT REVIEW .................................................... 3-1

4 EXISTING GEOTECHNICAL INFORMATION ................................................................. 4-1

5 RECENT FIELD EXPLORATION ..................................................................................... 5-1

5.1 Geology .................................................................................................................................... 5-1

5.2 Subsurface Explorations ......................................................................................................... 5-1

5.3 Boring Stakeout and Subsurface Utility Clearance ................................................................ 5-1

5.4 Drilling Methodology and Sampling ........................................................................................ 5-3

5.5 Seismic Cone Penetration Tests with Pore Pressure Measurements ................................... 5-3

5.6 Temporary Groundwater Wells ............................................................................................... 5-4

5.8 Environmental Soil Samples ................................................................................................... 5-4

5.9 Investigative Derived Waste .................................................................................................... 5-4

6 SUBSURFACE EXPLORATION RESULTS .................................................................... 6-1

6.1 Subsurface Conditions ............................................................................................................ 6-1

6.2 Groundwater ............................................................................................................................ 6-2

6.3 Soil Engineering Property Test Results .................................................................................. 6-2

6.4 Corrosion Testing .................................................................................................................... 6-3

6.5 Expected Variations in Subsurface Conditions ...................................................................... 6-4

7 GEOTECHNICAL ENGINEERING RECOMMENDATIONS............................................ 7-1

7.1 Spread Footings Supported on Natural Soils ......................................................................... 7-1

7.2 Spread Footings Supported on Densified Displacement Aggregate Piers ........................... 7-2

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7.3 Floor Slab Subgrade Recommendations ............................................................................... 7-3

7.4 Seismic Design Criteria ........................................................................................................... 7-4

7.5 Liquefaction Potential .............................................................................................................. 7-4

7.6 Restrained Walls ..................................................................................................................... 7-4

7.7 Pavement Areas ...................................................................................................................... 7-5

7.7.1 Light Duty Flexible POV Parking Lot ......................................................................... 7-5

7.7.2 Heavy Duty Flexible Pavements for Tactical Vehicles ............................................. 7-5

7.7.3 Wash Rack Concrete Pavement ............................................................................... 7-5

7.8 Mechanically Stabilized Earth (MSE) Retaining Wall ............................................................. 7-6

7.9 Temporary Slopes ................................................................................................................... 7-7

7.10 Pipe and Utility Bedding .......................................................................................................... 7-7

8 CONSTRUCTION CONSIDERATIONS ........................................................................... 8-1

8.1 Footing Subgrades .................................................................................................................. 8-1

8.2 Fill Subgrade Preparation ....................................................................................................... 8-1

8.3 Fill Placement and Compaction .............................................................................................. 8-1

8.4 Dewatering Effluent Handling.................................................................................................. 8-2

8.5 Other Design and Construction Considerations ..................................................................... 8-2

8.6 Construction Monitoring .......................................................................................................... 8-2

9 LIMITATIONS .................................................................................................................... 9-1

List of Figures and Appendices

Figure 1- Site Vicinity Plan (1 sheet)

Figure 2 & 3 – Historical Orthophotos (2 sheets)

Figures 4 & 5 – Soil Boring and SCPTu Location Plan (2 sheets)

Figure 6 – Restrained Wall Lateral Earth Pressures (1 sheet)

Figure 7 – Over Excavation and Backfill Beneath Footings (1 sheet)

Appendix A- Soil Boring Logs (46 sheets), USCS Soil Identification Sheet (2 sheets)

Appendix B – SCPTu Log and Correlation Graphs (5 sheets)

Appendix C – Utility Clearance Letter and Photographs (19 sheets)

Appendix D – Soil Profiles (9 sheets)

Appendix E – Soil Engineering Property Test Results (68 sheets)

Appendix F – Corrosivity Test Results (37 sheets)

Appendix G –Environmental Groundwater, Composite Soil Sample, and Investigative Derived Waste (IDW) Laboratory Results (8910 sheets)

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Appendix H – Geotechnical Calculations and Analysis (82 sheets)

Appendix I – SPT Hammer Calibration (29 sheets)

Appendix J – Historic Logs and Site Info by Others (453 sheets)

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1 INTRODUCTION AND SCOPE OF WORK

Task Order N4008523F5964 scope of work was provided in the “P1556 NAVFAC SAES Eng Services” RFP on March 23, 2023. The scope includes providing a geotechnical site characterization and engineering report, and hazardous materials survey and report, to support final design being developed under a separate contract. The report herein only includes the geotechnical site characterization and engineering report. The hazardous materials report has been submitted as a separate report.

Naval Facilities Engineering Command-Mid Atlantic (NAVFAC-MIDLANT) plans to construct an operational complex for 1st Battalion 10th Marines, Navy-Marine Expeditionary Ship Interdiction System NMESIS) and Remotely operated Ground Unit for Expeditionary Fires (ROUGE-FIRES) vehicle at Marine Corps Base (MCB) Camp Lejeune in Jacksonville, North Carolina. The complex will consist of the following structures:

Field Maintenance Shop [A1] – one new structure, approximately 16,120 SF

Humidity Controlled Warehouse [A2] – one new structure, approximately 46,771 SF

NMESIS weather shelters [A3] – six new overhead structures, approximately 17,917 SF

(2) 2-bay shelters [A3-1]

(2) 4-bay structures [A3-2]

(1) 5-bay structure [A3-3]

(1) 7-bay structure [A3-4]

Artillery Weather Shelter [A4] – one new overhead structure, approximately 2,071 SF

Electronics and Communications Shop Addition to Building 1445 [B1] – one new building addition, approximately 5,000 SF

HP500 Armory Addition [C1] – one new building addition, approximately 6,292 SF

Automotive Maintenance Shop Addition to Building 1450 [D1] – one new building addition, approximately 3,484 SF

Operational Hazmat and Flammable Storage Shelter [D2] – one new overhead structure, approximately 966 SF

Site improvements are also to include expanding both ends of the existing tactical vehicle wash rack, providing an approximately 100-space parking lot for privately owned vehicles (POV), paving for new drives and parking for tactical vehicles and supporting utilities and infrastructure.

AECOM’s scope of work for the subject project included drilling 25 soil borings, five offset temporary groundwater wells, performing one seismic cone penetration sounding with pore pressure measurements (SCPTu), performing soil laboratory testing, and reviewing the existing Geotechnical Engineering Reports for projects in the vicinity of the proposed project sites and preparation of this report. The scope includes preparation of a geotechnical engineering report

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based on the geotechnical data collected during our subsurface investigation with the following information:

A. A site vicinity map based on a USGS 7.5-minute quadrangle topographic map.

B. A soil exploration location plan.

C. Soil boring logs, SCPTu sounding log, and pavement cores.

D. Graphic and written subsurface profiles with SPT N-values, CPTu tip resistance, groundwater data and other pertinent geotechnical data obtained during exploration and testing, as appropriate.

E. A summary of prior subsurface investigations performed near the site based on the data provided in the SAES.

F. Discussion of current site conditions, site history and past development activities

G. Results of geotechnical soil laboratory testing, delineation of subsurface test data and statistical evaluation of this data.

H. Description of regional geology.

I. Foundation recommendations for support of the proposed structures.

J. Recommendations for floor slab preparation.

K. Seismic site class in accordance with the current version of ASCE 7 and IBC based on the shear wave velocity data collected with seismic testing in the CPTu sounding.

L. Recommendations for handling of groundwater in the design.

M. Lateral earth pressures and backfill recommendations for design of below grade walls.

N. Recommendations for earthwork requirements, including re-use of site soils for structural fill.

O. Recommended pavement sections for the light duty bituminous pavement, heavy duty bituminous pavement, and light duty Portland cement concrete pavement based on the lower bound estimated design CBR value for the material encountered during the subsurface investigation.

P. Recommendations for excavated soil management and disposal requirements for contaminated soil and groundwater.

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2 EXISTING SITE CONDITIONS AND PROPOSED CONSTRUCTION

The site for the 1st Battalion 10th Marines, Navy-Marine Expeditionary Ship Interdiction System (NMESIS) and Remotely operated Ground Unit for Expeditionary Fires (ROUGE-FIRES) vehicles is located within the grounds of MCB Camp Lejeune in Jacksonville, North Carolina. All of the proposed facilities with the exception of the HP500 Armory Addition are located with the closest intersection being Louis Road and Dogwood Street. The addition to the existing HP500 Armory building is located off O Street with the closest intersecting street being Julian C Smith Street. The armory site is approximately ¾ of a mile southwest of the other site. A site Vicinity Map is included as Figure 1.

Nine existing facilities will be demolished as part of the P-1556 project to create available compound space for the new facilities. The existing sites are developed areas with facilities, parking areas, and laydown areas. Additional information regarding proposed facilities is as follows:

2.1 Field Maintenance Shop [A1]

The proposed Field Maintenance Shop is presently occupied by single-story buildings, Building 1464 and Building 1465, that will be demolished as part of the P-1556 project. The existing buildings are believed to have been constructed in 2008 based on historic aerial imagery. The foundations of the existing buildings are unknown. Paved asphalt areas surround the existing buildings with parking along the west-side of Building 1464 and a storage area on the south-side of the building.

The existing grades around the buildings were observed to be generally flat with grades varying between approximately EL 23 feet and EL 24 feet. Several underground utility lines are known to be present at the site.

The proposed Field Maintenance Shop is anticipated to be a single-story building, approximately 16,000 SF (200 feet by 80 feet) and will have a maximum column load of 75 kips and maximum wall load of 7 kips/ft. The design floor live load is 100 psf. The proposed structure is expected to have a similar finished floor elevation (FFE) as existing grades. The exact FFE and future site grades were not available at the time this report was written but a FFE of 23 feet was assumed for calculations.

2.2 Humidity Controlled Warehouse [A2]

The proposed Humidity Controlled Warehouse is presently occupied by single-story buildings, Building 1461 and Building 1462, that will be demolished as part of the P-1556 project. The existing buildings are believed to have been constructed in 2008 based on historic aerial imagery. The foundations of the existing buildings are unknown. Paved asphalt areas surround the site. The existing elevations around the site vary between approximately EL 21 feet and EL 24 feet. Several underground utility lines are known to be present at the site.

The proposed Humidity Controlled Warehouse is anticipated to be a single-story, conventionally framed steel building with reinforced concrete masonry units (CMU) and brick veneer. The structure will be approximately 47,000 SF (330 feet by 140 feet) and will have a maximum column load of 100 kips and maximum wall load of 4 kips/ft. The design floor live load is 100 psf. The proposed structure is expected to have a finished floor elevation (FFE) approximately 2 to 4 feet higher than

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existing grades per information provided by the government. The exact FFE and future site grades were not available at the time this report was written but a FFE of 25 feet was assumed for calculations.

It is anticipated that a four-foot tall retaining wall will be required on the western side of the Humidity Controlled Warehouse [A2] from elevation 21 feet to 25 feet. At the toe of the wall, the site will continue to slope at a 3.5H:1V slope to elevation 14 feet.

2.3 NMESIS Weather Shelters [A3]

There are six new NMESIS Weather Shelters to be constructed at the site which will run along the southern boundary of the existing site in areas that are currently paved. The existing elevations around the site vary between approximately EL 21 feet on the west-end and EL 24 feet on the east-end. Several underground utility lines are known to be present at the site.

The proposed NMESIS Weather Shelters will be overhead canopy structures, about 18 feet tall, and totaling approximately 17,917 SF (all approximately 40 feet wide with varying lengths) and will have a maximum column load of 100 kips and maximum factored (LRFD) net uplift load of 10 kips and overturning moment of 275 kip-ft. The design floor live load is 100 psf.

The proposed west-most Weather Shelter [A3-4] is expected to have a finished floor elevation (FFE) approximately 2 to 4 feet higher than existing grades. The exact FFE and future site grades were not available at the time this report was written but a FFE of 25 feet was assumed for calculations.

The other five Weather Shelters [(2) A3-1,(2) A3-2, and (1) A3-3] are expected to have FFE’s at about existing grades. The exact FFE’s and future site grades were not available at the time this report was written but a FFE of 23 feet was assumed for calculations.

2.4 Artillery Weather Shelter [A4]

There will be one new Artillery Weather Shelter to be constructed at the site which will be located at the southeast corner of the existing site. The existing elevation around the proposed structure is approximately EL 23 feet. Several underground utility lines are known to be present at the site.

The proposed Artillery Weather Shelter will be an overhead canopy structure, about 18 feet tall, and totaling approximately 5,000 SF (110 feet by 40 feet) and will have a maximum column load of 100 kips and factored (LRFD) net uplift load of 10 kips and overturning moment of 275 kip-ft. The design floor live load is 100 psf. The Artillery Weather Shelter is expected to have a FFE at about existing grades. The exact FFE and future site grades were not available at the time this report was written but a FFE of 23 feet was assumed for calculations.

2.5 Addition to Building 1445 Communications and Electronics Shop [B1]

The proposed addition to Building 1445 Communications and Electronics Shop will be constructed at the west-end of existing Building 1445. The existing structure is a single-story building that is believed to have been constructed in the early 1990s based on historic aerial imagery. The existing building is believed to be supported on a shallow foundation. Paved asphalt areas surround the existing building with parking for tactical vehicles. The existing grades around the building were

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observed to be generally flat with grades varying between approximately EL 26 feet and EL 27 feet.

Several underground utilities including electric and water lines are known to be present at the site.

The proposed B1445 Addition is anticipated to be a single-story building, approximately 5,000 SF (120 feet by 42 feet) and will have a maximum column load of 75 kips and maximum wall load of 6 kips/ft. The design floor live load is 100 psf. The proposed addition is expected to have the same finished floor elevation (FFE) as the existing building. The exact FFE and future site grades were not available at the time this report was written but a FFE of 27 feet was assumed for calculations.

2.6 Addition to HP500 Armory [C1]

The proposed addition to the HP500 Armory building will be constructed at the northwest end of the existing HP500 Armory building. The existing structure is a single-story building that is believed to have been constructed in the early 2000s based on historic aerial imagery. The existing building is believed to be supported on shallow foundations although the as-built foundation drawings were not available at the time of the writing of this report. Part of the P-1556 project includes renovations to the existing HP500 Armory but any foundation work related to the renovation is not included in AECOM’s scope of work. Gravel areas surround the existing building with parking for tactical vehicles. The existing grades around the building were observed to be generally flat with grades varying between approximately EL 21 feet and EL 22 feet. Several underground utility lines are known to be present on the west and north sides of the site.

The proposed HP500 Armory Addition is anticipated to be a single-story building with high bay frames to accommodate storage and vehicle maintenance, approximately 6,200 SF (72 feet by 86 feet) and will have maximum a column load of 75 kips and maximum wall load of 4 kips/ft. The design floor live load is 100 psf. The proposed addition is expected to have the same finished floor elevation (FFE) as the existing building. The construction is anticipated to include renovations to the existing structure. The exact FFE and future site grades were not available at the time this report was written but a FFE of 22 feet was assumed for calculations.

2.7 Addition to Building 1450 Automotive Maintenance Shop [D1]

The proposed addition to Building 1450 Automotive Maintenance Shop will be constructed at the southeast end of the existing Building 1450. The existing structure is a single-story building that is believed to have been constructed in the early 1980s based on record drawings provided by NAVFAC. The existing building is believed to be supported on shallow foundations although as-built foundation drawings were not available at the time of the writing of this report. Paved asphalt areas surround the existing building, which are used as travel lanes and for tactical vehicle parking. The existing grades around the building were observed to be generally flat with grades varying between approximately EL 26 feet and EL 27 feet. Several underground utility lines are known to be present on the west and north sides of the site.

The proposed Building 1450 Addition will extend off the south side of the existing building and is anticipated to be a single-story building, approximately 3,150 SF (45 feet by 70 feet) and will have a maximum column load of 100 kips and maximum wall load of 6 kips/ft. The design floor live load is 100 psf. The proposed addition is expected to have the same finished floor elevation (FFE) as the existing building. The exact FFE and future site grades were not available at the time this report was written but a FFE of 26 feet was assumed for calculations.

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2.8 Hazards and Flammable Storage Shelter [D2]

There will be one new Hazards and Flammable Storage Shelter to be constructed at the site which will be located on the northwest portion of the existing site, just east of the Vehicle Wash Rack. The existing ground surface elevation around the proposed structure is approximately EL 24 feet.

Several underground utility lines such as electric, water, and sewer are known to be present west of the proposed structure.

The proposed Hazards and Flammable Storage Shelter will be a Pre-Engineered Metal Building (PEMB) frame structure with standing metal roofing, about 10 feet tall, and totaling approximately 1,000 SF (15 feet by 65 feet) and will have maximum column loads of 100 kips and maximum wall loads of 4 kips/ft. The design floor live load is 100 psf. The Hazards Shelter is expected to have a FFE at about existing grades. The exact FFE and future site grades were not available at the time this report was written but a FFE of 24 feet was assumed for calculations.

2.9 Wash Rack Extension

The Vehicle Wash Rack extension will extend the existing wash racks by approximately 25 feet on each end of the existing structures. Concrete pavement will be installed adjacent to the existing wash racks to construct the new racks.

2.10 POV Parking Lot

The proposed Privately Owned Vehicle (POV) Parking Lot will provide 100 parking stalls and 10 motorcycle spaces. The POV Lot will be located south of existing Building 1450. Currently, Buildings 1450A and 1450B occupy the proposed footprint of the POV lot and will be demolished as part of the P-1556 project. The POV lot will be paved with flexible pavement. Proposed parking lot and future site grades were not available at the time this report was written, although it is assumed that new grades will be similar to existing ground surface grades.

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3 HISTORICAL IMAGERY AND DOCUMENT REVIEW

We have reviewed historical aerial imagery on Google Earth dating as far back as 1993 and available Onslow County, NC soil and topographic maps including: United States Department of Agriculture (USDA) Onslow County, NC Soils Maps, 1921 and United States Geologic Survey (USGS) Camp Lejeune North Carolina 7.5’x7.5’ Topographic Map, 1952 original, revised in 1971.

We have also reviewed drawings of the Counter Artillery Battery Radar Platoon Grading, Drainage, and Erosion Control from 2008 provided by the MCB Public Works Department (PWD).

Based on our review, the site for the proposed Field Maintenance Shop [A1], Humidity Controlled Warehouse [A2], NMESIS Weather Shelters [A3] and Artillery Weather Shelter [A4] were initially developed from about 2008 to 2011. Prior to 2008, this site appears to have been heavily wooded.

Site development from 2008 to 2011 appears to have included significant regrading of the site, with over 10 feet of new fill constructed in places. Site conditions do not appear to have changed significantly since 2011.

Both Building 1445 and Building 1450 were constructed prior to 1993 based on Google Earth aerial imagery. It appears that the site conditions surrounding both buildings have not changed significantly since 1993. Historical orthophotos dating back to 1993 of the area surrounding the P-1556 site (other than the HP500 Armory) are included as Figure 2.

Based on historical aerial imagery, the original HP 500 Armory building was constructed in the early 2000s and the footprint of the proposed HP500 Armory Addition [C1] was included in the original early 2000s site development. The site is clear of trees and is currently a grass area next to the existing building. Prior to 2002, the Armory building site was a wooded area. The current site conditions do not appear to have changed significantly since the Armory was first constructed in 2002. Historical orthophotos dating back to 1993 of the area surrounding the HP500 Armory are included as Figure 3.

As shown on the MCB Camp Lejeune and MCAS New River PFAS Detections map, the main P- 1556 project site location area appears to have been a former industrial area fly ash dump site and there has been potential PFAS release in this area. The PFAS map provided by the government is included in Appendix J.

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4 EXISTING GEOTECHNICAL INFORMATION

We have reviewed and considered in our analysis the geotechnical information provided by the government. The following historic documents were provided to us as attachments in the government’s Scope of Architect-Engineer Services (SAES) dated March 23, 2023:

1. Report of Subsurface Investigation for Electronics Communication Maintenance Facility, prepared by S&ME Inc., dated July 22, 1987

2. Geotechnical Engineering Analysis for proposed P-150 10th Marines Armory, prepared by ECS Ltd, dated June 4, 2001

3. Geotechnical Site Characterization Report, P1495 – 10th Marines HIMARS Complex, prepared by HDR, Inc., dated April 12, 2019

4. Report of Subsurface Exploration and Revised Geotechnical Evaluation, P-1495 5th Battalion – Warehouse Site, prepared by Building & Earth Sciences, Inc., dated April 1, AECOM considers that the data presented in the existing documents is fairly consistent with the findings from our recent subsurface investigation. There were not any known subsurface investigations and historic boring logs on the western side of the site where deeper, uncontrolled fill was generally observed. It appears that the greater uncontrolled fill depths encountered in our recent soil borings coincide with the 2008 site re-grading in the areas of Buildings 1461, 1462, and 1463, where up to about 10 ft of new fill is believed to have been placed. This is also the location of the proposed Humidity Controlled Warehouse [A2] and west-most NMESIS weather shelter [A3].

It should be noted that AECOM assumes no responsibility for the accuracy or completeness of data obtained from the previous soil borings drilled at the site by others, as we were not present during the field investigations.

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5 RECENT FIELD EXPLORATION

5.1 Geology

The P-1556 project sites are located within the North Carolina Atlantic Coastal Plain physiographic province. The Coastal Plain providence 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.

The upper geologic units at the sites consist of unconsolidated Holocene deposits and Upper Pleistocene age deposits of undivided members. Older underlying units include consolidated Tertiary deposits of the Yorktown and Duplin Formations, undivided, described as fossiliferous clay and shelly sand deposits. Bedrock is believed to be at more than 1000 feet below sea level.

Locally, the P-1556 project site is underlain by the Tertiary-aged Belgrade Formation., undivided.

The Belgrade Formation consists of two members, the Pollocksville Member and the Haywood Landing Member that grade laterally into each other. The Pollocksville Member generally consists of oyster-shell mounds in tan to orange sand matrices. The Haywood Landing Member generally consists of gray to brown, fossiliferous clayey sand (NCGS, 1985).

Uncontrolled fill was observed in almost all of the soil borings. The uncontrolled fill soils are believed to be associated with the previous development of the proposed sites. Based on environmental maps provided by the government, the proposed P-1556 site was a previous Industrial Area Fly Ash Dump Site.

5.2 Subsurface Explorations

AECOM conducted a subsurface investigation program to investigate the subsoil conditions within the proposed sites within MCB Camp Lejeune, North Carolina. A total of 25 soil borings, labeled B- 01 through B-22 (minus B-20 which was removed from our scope by the government) and P-01 through P-04 and one seismic CPTu, SCPTu-01, were performed as part of the subsurface investigation. A field investigation workplan and Quality Control (QC) Checklist was prepared and approved by NAVFAC prior to starting the field investigation. The soil boring and SCPTu locations are illustrated on the Soil Boring and SCPTu Location Plans included as Figures 4 and 5. The soil boring and SCPTu logs are included in Appendix A and B.

5.3 Boring Stakeout and Subsurface Utility Clearance

The boring and CPTu locations were field located and marked by AECOM subconsultant GER based on GPS coordinates prior to drilling the borings to identify utilities and to “clear” the boring locations. North Carolina 811 was contacted by our drilling subcontractor, Fishburne Drilling, Inc., to mark the existing underground public utilities around staked boring locations. Additionally, the boring and SCPTu locations were cleared by private utility locator GPRS, Inc using non-destructive methods such as Ground Penetrating Radar (GPR), pipe locators, metal detectors, etc. A letter from GPRS, Inc and photo logs of the cleared locations are included in Appendix C.

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The as-drilled coordinates were marked using a Trimble Geo7000 GPS. The government site surveys were not available at the time of this writing. Therefore, the ground surface elevations at the soil boring and CPTu locations were obtained from the as-built grading and utility plans provided by the Public Works Department (PWD). The coordinates and approximate ground surface elevations at the soil boring and SCPTu locations are shown on the boring logs included in Appendix A and the approximate soil boring and SCPTu locations are illustrated on the Boring Location Plans included as Figures 4 and 5. The soil boring and CPTu coordinates, elevations and termination depths are summarized in the table below.

Table 1: Summary of Subsurface Explorations

Boring ID Structure Termination

Depth (ft) Northing* Easting*

Approximate Ground Surface

Elevation (feet)

B-01 Bldg 1445 Addition [B1]

30 337259.27 2501007.34 27

B-02 30 337169.74 2501094.05 27

B-03 Bldg 1450 Addition

[D1] 30 337063.09 2501607.10 26

B-04 Hazmat Flammable

Storage [D2] 15 336906.17 2501293.96 24

B-05

Field Maintenance Shop [A1]

35 336785.72 2502067.88 23.2

B-06 30 336723.81 2501993.74 23.3

B-07 30 336668.30 2501939.54 23

B-08 30 336645.48 2502025.13 23.3

B-09 50 336726.17 2502134.05 23.1

B-10 NMESIS Weather

Shelter [A3-1 & A3-3] 50 336567.14 2502056.52 23

B-11

Humidity Controlled Warehouse [A2]

35 336712.44 2501678.15 24

B-12 30 336641.09 2501764.56 23

B-13 50 336573.12 2501690.52 22

B-14 50 336594.60 2501524.75 22

B-15 30 336493.02 2501616.68 22

B-16 50 336400.28 2501512.98 21.7

B-17 30 336508.18 2501435.98 21

SCPTu-01 85 336662.83 2501613.83 22.5

B-18 NMESIS Weather

Shelter {A3-4] 50 336389.92 2501618.41 21

B-19 Artillery Weather

Shelter [A4] 50 336753.46 2502314.03 23.5

B-21 HP500 Armory Addition [C1]

30 333440.30 2498640.19 22

B-22 30 333381.07 2498726.40 22

P-1 Wash Rack

10 336879.81 2501169.09 22

P-2 10 336766.43 2501281.27 22

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P-3 POV Parking Lot

10 337053.07 2501732.57 24

P-4 10 336827.41 2501661.18 25

* NAD83, North Carolina State Plane (US Survey Feet)

5.4 Drilling Methodology and Sampling

Fishburne Drilling, Inc. of Chesapeake, Virginia drilled the soil test borings, B-01 through B-22 and P-1, P-2, P-3 and P-4 between September 25th, 2023, and October 6th, 2023. Fishburne Drilling, Inc, conducted the drilling of the soil borings as licensed well drillers in the State of North Carolina

(NCWC 4366-A & NCWC 4174-B).

The borings performed by Fishburne Drilling, Inc. were drilled with a truck mounted CME-45 using hollow stem auger (HSA) drilling methods to drill the temporary groundwater wells and mud rotary drilling methods to advance all other borings which extended below the groundwater table.

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 upper 12 feet and every five feet below the upper 12 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 with cement/bentonite grout upon completion in accordance with the approved Geotechnical Investigation QA Checklist.

After recovery, the soil samples were removed from the sampler and visually classified by a senior geologist from our AECOM office. Representative portions of the soil samples were sealed in glass jars and retained for further review. The visual classifications were based on texture and plasticity, in accordance with the Unified Soil Classification System (USCS). A brief description of the USCS is also included in Appendix A.

5.5 Seismic Cone Penetration Tests with Pore Pressure Measurements

One seismic CPTu sounding (SCPTu-01) was performed by In-Situ Soil Testing, Inc. within the proposed building footprint of the Humidity Controlled Warehouse in general accordance with ASTM D5778 20, “Standard Test Method for Electronic Friction and Piezocone Testing of Soils”.

The SCPTu was planned to be extended to a depth of 100 ft; however, refusal was encountered at a depth of 85 feet below the ground surface. The SCPTu recorded tip resistance, side friction, and pore pressure. Shear wave velocity data was recorded at 3-ft (1 meter) depth intervals in the SCPTu. The SCPTu-01 data log is included in Appendix B. Graphical correlations with SPT N-values, CPTu tip resistance, friction ratio percentage and percent Passing #200 are also included in Appendix B. Additionally, SCPTu-01 is plotted in the soil profile for the Humidity Controlled Warehouse site included in Appendix D. The SCPTu-01 location is illustrated in the Soil Boring and SCPTu Location Plan included as Figure 4.

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5.6 Temporary Groundwater Wells

Five temporary groundwater wells were drilled as offsets to borings B-04, B-07, B-15, B-19, and B-21. Each well was drilled to approximately 15 feet bgs to 18 feet bgs to obtain groundwater samples for environmental testing and chemical analysis. Groundwater level readings were collected from the temporary groundwater wells after 24-hours and 48-hours. Groundwater level readings from the temporary wells are included on the boring logs in Appendix A.

Groundwater samples were collected following the 48-hour readings. Once groundwater samples were collected, the temporary wells were abandoned by the drilling subcontractor. The groundwater samples were sent to Advanced Environmental Laboratories, LLC in Jacksonville, FL for the following chemical analyses: PFAS, TPH-DRO, TPH-GRO, TAL metals, TCL VOCs, and TCL SVOCs. Results are presented in Appendix G.

5.7 Photoionization Detector (PID) Screening

All soil samples recovered from the borings were screened for volatile organic compounds (VOCs) using a photoionization detector (PID). The PID readings obtained in the field from the samples recovered varied from less than one part per million (ppm) to 1.8 ppm. The PID readings are included in the soil boring logs in Appendix A.

5.8 Environmental Soil Samples

Six composite soil samples were collected from depths of 1 ft to 5 ft bgs from borings B-02, B-06, B-14, B-18, B-21, and P-02. The samples were collected to preliminarily assess disposal requirements for the construction excavation spoils. The composite samples were sent to Advanced Environmental Laboratories, LLC in Jacksonville, FL for the following chemical analyses: TCLP (VOCs, SVOCs, pesticides/herbicides, metals, PCBs), TPH-DRO, TPH-GRO, PFAS, ignitability, corrosivity, and reactivity. Disposal requirements are discussed in section 8 and chemical analysis results are presented in Appendix G.

5.9 Investigative Derived Waste

All investigative derived waste (IDW) from the soil borings was handled in accordance with the approved Geotechnical Investigation Work Plan and QA Checklist. The IDW was stored in 20 US Department of Transportation (USDOT) approved 55-gallon drums. The drums were sealed, labeled, and stored at a selected location approved by the MCB Camp Lejeune Environmental Management Division point of contact. Three composite samples of the soil spoils and two composite IDW liquid samples were obtained from the drums for environmental IDW disposal testing. The environmental test results are included in Appendix G. The drum removal from the site is currently being coordinated with our subcontractors and drums will be disposed of based on the environmental laboratory test results.

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6 SUBSURFACE EXPLORATION RESULTS

6.1 Subsurface Conditions

The subsurface materials encountered in the soil borings are described 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 and parent geology. The subsurface materials encountered in the soil borings, along with the range of Standard Penetration Test (SPT) N-Values are described below.

Up to approximately 3 inches of organic surficial soil, 7.5 inches of asphalt and 8.25 inches of concrete were encountered at the soil boring locations. These depths should not be considered a stripping depth since the organic surficial soil, asphalt and concrete may be thicker at other areas of the site. Subsurface soil profiles were prepared illustrating subsurface soil conditions at each proposed structure (including the CPTu data) and are included in Appendix E.

Stratum A: Uncontrolled Fill

All the soil borings, except boring B-22, indicated the presence of uncontrolled fill soils below the organic surficial soil, asphalt and concrete. The uncontrolled fill extended to depths of between about 2.6 feet and 13.0 feet below the existing ground surface or between about EL +22.5 feet and EL +8.0 feet. Standard Penetration Test N-values for the uncontrolled fill soils vary between 2 blows per foot (bpf) to 35 bpf.

CPTu corrected tip resistance for the existing uncontrolled fill soils varies approximately between 15 tons per square foot (tsf) and 200 tsf. The effective friction angle of the cohesionless soils is between 370 to 500. The friction angle was estimated using the Robertson method.

Stratum B1: (Coastal Plain- Alluvial Cohesionless Soils)

Below the uncontrolled fill soils, sandy natural soils were encountered in all borings, to termination depths with the deepest termination depth being 50 feet below existing grades, or to about El -

26.0. The sandy natural soils consisted of very loose to dense Silty Sand (SM), Clayey Sand (SC), Poorly Graded Sand (SP), Poorly Graded Sand with Silt (SP-SM), Silty Clayey Sand (SC-SM), Silty Gravel with Sand (GM), Silty Sand with Gravel (SM), and Silty Gravel (GM). The N-values ranged from 0 bpf to 31 bpf. All soil borings and the SCPTu terminated in this Stratum.

CPTu corrected tip resistance for the existing soils varies approximately between 20 tsf and 300 tsf. The effective friction angle of the cohesionless soils is estimated to vary between 320 to 440.

The friction angle was estimated using the Robertson method.

Stratum B2: (Coastal Plain – Alluvial Cohesive Soils)

In borings B-08, B-15, and B-17, cohesive soils were encountered below the uncontrolled fill soils.

Below the Stratum B1 cohesionless soils in borings, B-03, B-04, B-05, B-06, B-08, B-09, B-10, B- 12, B-13, B-15, B-16, B-17, B-19, B-21, and B-22 cohesive soils were encountered to depths between about 8.5 feet and 25 feet below existing grades or between about El 13 feet and El -3.

These soils consisted of very soft to medium stiff Sandy Lean Clay (CL), Lean Clay with Sand

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(CL), Fat Clay with Sand (CH), and Fat Clay (CH). The N-values ranged from 1 bpf to 6 bpf. There was no B2 cohesive soil layer noted in the SCPTu-01 log.

6.2 Groundwater

Groundwater readings obtained from the temporary groundwater wells are summarized below.

The groundwater measurements were obtained 24-hours and 48-hours after temporary well construction. Groundwater level readings were not recorded for borings drilled with mud rotary due to the introduction of drilling fluids to the borehole and water levels would have been inaccurate. Borings without temporary groundwater wells were grouted upon boring completion due to logistic reasons at the site. Temporary wells were abandoned and grouted prior to field work completion and demobilizing from the project site.

Groundwater depths ranged from 8.2 feet bgs to 13.8 feet bgs or between Elevation 8.2 and 15.8 feet. The temporary well groundwater observations are also included in the soil boring logs included in Appendix A.

Mud drilling methods were used to perform the soil borings and drilling fluid was introduced during the drilling process. Therefore, groundwater measurements were not obtained upon completion of the borings. Seasonal 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 groundwater levels are higher than those obtained from the soil borings. Seasonal high water table levels are anticipated to be approximately 5 to 7 feet below existing grades. 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, sea level tides, evaporation, construction activity, surface runoff, and other site-specific factors.

6.3 Soil Engineering Property Test Results

Select split-spoon soil samples were tested to determine the physical and engineering properties of the on-site soils. The soil laboratory tests were conducted by GeoEnvironmental Resources’ (GER) in general accordance with applicable ASTM criteria. The testing included moisture content determinations (ASTM D2216), Atterberg Limits tests (ASTM D4318), mechanical gradation analyses (ASTM D6913), incremental load 1-D consolidation tests (ASTM D2435), and one Unconsolidated Undrained (UU) triaxial compression test (ASTM D2850), CBR tests (ASTM D1833), and Standard Proctor tests (ASTM D698). The GER Soil Laboratory certifications and the soil laboratory test results are included in Appendix E. Additionally, some of the test results such as moisture content and Atterberg Limit results are incorporated in the soil boring logs in Appendix A. The CBR test results are summarized in the table below:

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Table 2: CBR Laboratory Test Results

6.4 Corrosion Testing

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. Six composite soil samples were obtained from recent soil borings B-02, B-06, B-14, B-18, B-21, and P-02 and were tested to determine the corrosion potential of the soils in the project area. The exact depths and locations of the proposed ductile iron pipes were not known at the time of the field exploration.

Samples were selected for corrosion testing based on the typical depths of such pipes. The American Water Works Association (AWWA) standard C-105 (Polyethylene Encasement for Ductile-Iron Pipe System) and the Ductile Iron Pipe Research Association (DIPRA) 10-Point System were used to assess the corrosion potential of the soil based on the soil resistivity, redox potential, pH, sulfide/sulfate concentrations, and moisture of the soils. The testing was performed in accordance with the ASTM standards. The soil laboratory test results for the corrosivity testing are included in Appendix F and summarized in the table below.

Table 3: Corrosivity Test Results Summary

Boring ID Proposed Site pH Chloride

(ppm) Sulfate (ppm)

Saturated Resistivity (ohm-cm)

Oxidation- Reduction Potential

(mV)

B-02 B1445 Addition [B1] 7 <21 540 26,840 110

B-06 Field Maintenance

Shop [A1]

7.5 <22 690 26,170 130

B-14 Humidity Controlled

Warehouse [A2]

7.5 <22 950 32,840 110

B-18 NMESIS Weather

Shelter [A3-3]

7.6 <22 280 22,840 110

B-21 HP500 Armory Addition [C1]

7.7 <21 120 21,500 110

P-02 Wash Rack Extension 7.7 <22 140 23,670 100

Based on the test results, soil samples tested for corrosion potential obtained from borings B-02, B- 06, B-14, B-18, B-21, and P-02 are not considered corrosive to ductile iron pipe according to AWWA C-105 criteria.

Site Location Sample ID Sample Depth (feet)

Sample Description

CBR at 0.2-inch

As-Molded Compaction

Wash Rack Extension

P-01 1 - 3' SP-SM 12.3 95.9

P-02 1 - 3' SC-SM 6.8 96.0

POV Parking Lot

P-03 1 - 3' SC-SM 14.5 96.1

P-04 1 - 3' SC-SM 3.1 95.9

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It should be noted that UFC-3 570-01-2016 Section 2-2.6 mandates any soils with resistivity under 30,000 ohm-cm be considered corrosive for ductile iron pipes. Therefore, based on the test results, soil samples tested for corrosion potential obtained from borings B-02, B-06, B-18, B-21, and P-02 are considered corrosive to ductile iron pipe. The decision to provide corrosion protection should be made by a competent corrosion expert.

The test results indicated a low to moderate sulfate concentration on the samples tested. Based on the American Concrete Institute (ACI 318), soils with water-soluble sulfate content less than 150 parts per million (ppm), where ppm is equal to 1 mg/kg, are categorized as having an exposure class of S0 (negligible sulfate severity), and the concern of injurious sulfate attack on concrete at this level of soil sulfate concentration is considered minimal. Soils with water-soluble sulfate content between 150 parts per million (ppm) and 1,500 ppm are categorized as having an exposure class of S1, where injurious sulfate attack on concrete at this level of soil sulfate concentration is a concern. The final selection of the cement grade and approval of the concrete mix should be performed by the project structural engineer.

6.5 Expected Variations in Subsurface Conditions

Interpretation of general subsurface soil conditions presented herein is based on the soil and groundwater conditions obtained from the soil borings drilled at the sites. The subsurface conditions may vary between exploration locations. If conditions are found to be different from those observed in the recent 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, proximity of the site to the coast, tidal changes, climate, construction in the area, etc., groundwater conditions at the time of construction may be different from those found during the time of the recent exploration.

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7 GEOTECHNICAL ENGINEERING RECOMMENDATIONS

The geotechnical engineering analysis was based on the soil boring data, SCPTu data, soil laboratory testing, and the project information included in Section 2 of this report. The geotechnical calculations and analyses packages are included in Appendix H of this report.

New soil borings indicate that existing fill soils are present in most of the proposed structure areas.

There is no information to verify that the existing fill was placed in a controlled manner. Therefore, it has been considered that the existing fill is loose and that it was not properly compacted during placement.