Attachment A-1626397_Q997_RFP_Vol I of II_File 4 of 5.pdf

Attachment D

Q997 GEOTECHNICAL REPORT

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4525 Main Street, Suite 1400 Virginia Beach, VA 23462

Navy Region Mid-Atlantic

GEOTECHNICAL REPORT

FINAL SUBMITTAL

23 April 2020

Contract No.: N40085-15-D-0068, Task Order No. N4008518R1102 Project: FY21 MCON Project Q997 SOF NSWG-2 Combat Service Support Facilities JEB Little Creek-Fort Story, Virginia Beach, VA eProjects Work Order No.: 1626397 CN#8342

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GEOTECHNICAL

DATA REPORT

P997 SOF NSWG-2 Combat Service Support Facilities

Virginia Beach, Virginia

G E T Project No: VB19-279G

February 21, 2020

PREPARED FOR:

5465 Greenwich Road Virginia Beach, VA 23462 Phone: (757)-518-1703 www.getsolutionsinc.com

5465 Greenwich Road Virginia Beach, VA 23462 Phone: (757)-518-1703 Fax: (757)-518-1704 info@getsolutionsinc.com

February 21, 2020

TO: Naval Facilities (NAVFAC) Mid Atlantic c/o Clark Nexsen 4525 Main Street Suite 1400 Virginia Beach, VA 23462

Attn: Mr. Steve Bennett, PE

RE: Geotechnical Data Report P997 SOF NSWG-2 Combat Service Support Facilities Contract Number: N40085-19-D-9041 Joint Expeditionary Base Little Creek-Fort Story, Virginia Beach, Virginia G E T Project Number: VB19-279G

Dear Mr. Bennett:

In compliance with your instructions, we have completed our Subsurface Exploration and Geotechnical Services for the above referenced project. The results of this study are presented in this report.

We appreciate the opportunity to work with you on this project. We trust that the information contained herein meets your immediate need, and should you have any questions or if we could be of further assistance, please do not hesitate to contact us.

Respectfully Submitted, G E T Solutions, Inc.

Jennifer Maginniss Staff Engineer, EIT

Bruce R. Spiro, P.E.

Principal Engineer VA Reg. # 015791

Copies: (1) Client

TABLE OF CONTENTS

Geotechnical Data Report February 21, 2020

G E T Project No: VB19-279G

1.0 PROJECT INFORMATION

1.1 Purpose and Scope of Services

1.2 Project Authorization

1.3 Project Location and Description

1.4 Project Construction Description

1.5 Site Geology

1.6 Recent Land Reclamation and Site Development

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

2.2 Field and Laboratory Testing

2.2.1 Soil Classification and Index Testing

2.2.2 Bulk Soil Sample Testing

2.2.3 In-Situ Permeability Testing

2.2.4 Consolidation Testing

2.2.5 Chemical Analysis

3.0 SITE AND SUBSURFACE CONDITIONS

3.1 Subsurface Soil Conditions

3.2 Groundwater Discussion

4.0 REPORT LIMITATIONS

APPENDIX I BORING LOCATION PLANS

APPENDIX II SOIL CLASSIFICATION SYSTEM

APPENDIX III SUMMARY OF LABORATORY RESULTS

APPENDIX IV BORING LOGS

APPENDIX V SOIL PROFILES

APPENDIX VI CORE LOGS

APPENDIX VII CONETEC CPT AND DMT REPORT

APPENDIX VIII CBR TEST RESULTS

APPENDIX IX INFILTRATION TEST RESULTS

APPENDIX X SHELBY TUBE CLASSIFICATION

APPENDIX XI CONSOLIDATION TEST RESULTS

APPENDIX XII ENVIRONMENTAL TEST RESULTS

APPENDIX XIII HISTORICAL SITE INFORMATION

Geotechnical Data Report February 21, 2020

1.0 PROJECT INFORMATION

1.1 Purpose and Scope of Services

The purpose of this study was to obtain information on the general subsurface conditions at the proposed project site. In this regard, information for the following items were formulated:

1. General assessment of the soils revealed by the borings and testing performed at the proposed development.

2. General location and description of potentially deleterious material encountered in the borings that may interfere with construction progress or structure performance, including existing fills or surficial/subsurface organics.

3. Presentation of soil sample chemical analysis results and soil corrosivity characteristics and properties.

Other than the defined scope of work, the scope of services did not include any additional environmental assessment for determining the presence or absence of wetlands or hazardous or toxic material in the bedrock, surface water, groundwater or air, on or below or around this site.

1.2 Project Authorization

G E T Solutions, Inc. has completed our subsurface exploration and geotechnical services for the proposed P997 SOF NSWG-2 Combat Service Support Facilities project located at the Joint Expeditionary Base Little Creek-Fort Story in the City of Virginia Beach, Virginia. The geotechnical services were conducted in general accordance with the revised scope presented in G E T Proposal No. PVB19-259G dated March 20, 2019 and in the revised proposal dated November 6, 2019. The revised proposal was submitted due to a reissued SAES containing additional scope. Authorization to proceed with our services was received from the client on September 5, 2019 in the form of electronic mail for the original scope and on December 12, 2019 for the revised scope.

1.3 Project Location and Description

There are five separate sites included in the scope of this project:

Parking Lot:

This project site is located northeast of the intersection of Cove Road and Helicopter Road within the Little Creek/Fort Story Base in the City of Virginia Beach, Virginia. The site is currently occupied by a parking lot, equipment storage areas, and several structures. Approximate existing ground elevations are between 6.5 and 9.5 feet (NAVD88).

Armory Addition:

This project site is located northwest of the intersection of Gator Blvd. and Helicopter Road within the Little Creek/Fort Story Base in the City of Virginia Beach, Virginia. The site is currently a paved parking area within a secured compound bordered by several structures and roadways.

The existing armory structure is directly south of the armory addition site. Approximate existing elevations are between 7.5 and 10.5 feet (NAVD88).

Ordnance Operations:

This project site is located northwest of the intersection of Murray Road and Magazine Road within the Little Creek/Fort Story Base in the City of Virginia Beach, Virginia. The site currently contains a grassy field, a one story structure, and a parking lot and is bordered by several roadways and a wooded area. Approximate existing ground elevations are between 12.5 and

15.5 feet (NAVD88).

Boat Canopy:

This project site is located southeast of the intersection of Cove Road and Helicopter Road within the Little Creek/Fort Story Base in the City of Virginia Beach, Virginia. The site is currently a parking lot bordered by several structures and roadways. Approximate existing ground elevations are between 6 and 9.5 feet (NAVD88).

Vehicle Maintenance and Boat Shop:

This project site is located at the cul-de-sac of Knox Road and north of Amphibious Drive within the Little Creek/Fort Story Base in the City of Virginia Beach, Virginia. The site is currently an open grassy field containing several structures, roadways, and wooded areas. Approximate existing ground elevations are between 8 and 16 feet (NAVD88), with the exception of the special access area which has an approximate elevation of 24 feet (NAVD88).

A site vicinity map of all five sites is presented in Figure 1.

Figure 1: Site Vicinity Map

Source: U.S. Geological Survey, Little Creek Quadrangle, 2016

RED – Parking Lot; ORANGE – Armory Additions; GREEN – Ordnance Operations;

BLUE – Boat Canopy; PURPLE – Vehicle Maintenance and Boat Shop

1.4 Project Construction Description

Parking Lot:

This site includes demolition of Buildings 3807 and 3859 and installation of new infrastructure such as parking lots and a BMP pond. No significant grade changes are expected.

Armory Addition:

This site includes construction of a 13,000 square foot two-story armory expansion, including a 20 foot paved clear zone for a trailer loading area within a currently paved parking area.

Anticipated ground floor live loads may be up to 500 psf and anticipated maximum wall and column loads may be on the order of 3 klf and 400 kips, respectively. The addition’s finish floor elevation will coincide with the existing armory finished floor elevation. Accordingly, fills of 1 to 3 feet are expected. It is anticipated that the building superstructure may utilize structural steel framing with perimeter concrete masonry unit walls.

Parking Lot Boat Canopy

Armory Addition

Vehicle Maintenance and Boat Shop Ordnance

Operation

Ordnance Operations:

Construction on this site includes the demolition of Building 772 followed by its replacement with a paved parking and laydown area and construction of a new, approximately 3,300 square foot, single-story ordnance operations building. Anticipated ground floor live loads may be up to 100 psf (for handling and storage of ammunition). Anticipated maximum wall and column loads may be on the order of 2 klf and 50 kips, respectively. The building finish floor elevation is anticipated to be on the order of 3 to 4 feet above existing site grades.

Boat Canopy:

The boat canopy structure is planned to be a roughly 20,000 square foot open metal structure that has typical wall and column loads of 1 klf and 50 kips, respectively. Anticipated ground floor live loads may be up to 250 psf. The building finish floor elevation is anticipated to be up to 1 foot above existing site grades.

Vehicle Maintenance and Boat Shop:

This site includes construction of a 52,500 square foot boat maintenance and storage compound, a 20,500 square foot boat shop, a 28,000 square foot paved laydown area, and a 4,000 square foot paved wash pad area. The wash pad area is expected to consist of heavy duty concrete pavement. For the vehicle maintenance and boat shop structures, anticipated ground floor live loads may be up to 250 psf and anticipated maximum wall and column loads may be on the order of 1 to 2 klf and 50 kips, respectively. The building/structure finish floor elevations are anticipated to be on the order of 1 to 3 feet above existing site grades. The specific wash pad loading information is unknown at this time, however, it is expected to primarily consist of truck loading. The project also includes related infrastructure such as parking lots, BMP ponds, and utility installations.

If any of the noted information is incorrect or has changed, please inform G E T Solutions, Inc. so that we may amend the discussions presented in this report, if appropriate.

1.5 Site Geology

The project site lies within a major physiographic province called the Atlantic Coastal Plain.

Numerous transgressions and regressions of the Atlantic Ocean have deposited marine, lagoonal, and fluvial (stream lain) sediments. The regional geology is very complex, and generally consists of interbedded layers of varying mixtures of sands, silts, and clays. Based on our review of existing geologic and soil boring data, the geologic stratigraphy encountered in our subsurface explorations contains formations from the Pliocene Epoch.

The formation of the Pliocene Epoch encountered within the project limits consists of the Yorktown Formation (Ty). The Yorktown Formation is typically characterized by its blue-gray and green-gray color, distinct compact nature and the abundance of marine shell fragments.

The Yorktown Formation stratum, once encountered, generally extends to depths of several hundred feet below sea level.

1.6 Recent Land Reclamation and Site Development

We reviewed historical United States Geological Survey (USGS) topographic maps of Virginia Beach, Virginia produced between the years of 1902 and 2016 along with Google Earth aerial imagery from the years of 1990 to 2018 to evaluate the site development over time.

Review of these maps indicated that between 1902 and 1907, the Little Creek Base was just beginning to be constructed. After 1964, the maps show the Little Creek base as a solid white footprint, apart from the major roads, meaning that the site information is secured. As such, aerial imagery is used from 1990 onwards.

Parking Lot:

Overall the maps and images illustrate that the site is located directly adjacent to a previously reclaimed area and has contained buildings that have since been demolished.

This project site location appears to be adjacent to reclaimed land. Between 1918 and 1964, additional roads were constructed on the land adjacent to the site. Between 1964 and 1990, several buildings were constructed adjacent to and on the project site. Between 1994 and 2003, one of the existing buildings on the site was demolished and the asphalt and concrete portions of the site were paved. Between 2006 and 2018, one of the remaining buildings on site was extended and two more buildings were constructed.

Armory Addition:

Overall the maps and images illustrate that the site is located directly adjacent to a previously reclaimed area and has contained infrastructure that has since been demolished.

This project site location appears to be adjacent to reclaimed land. Between 1918 and 1964, additional roads were constructed on the land adjacent to the site. Between 1964 and 1990, several buildings were constructed adjacent to the project site. Between 1994 and 2003, the building directly west of the project site was constructed. Between 2003 and 2016, the site was used as an asphalt parking lot. Between 2016 and 2018, the building to the south of the project site was constructed and the project area was converted to a concrete loading area.

Ordnance Operations:

Overall the maps and images illustrate that the site is located within a previously reclaimed area and may have contained infrastructure that has since been demolished.

This project site location appears to be in a previous waterway between two islands, indicating that it is reclaimed land. This is reinforced by the amount of fill recovered in the borings.

Between 1918 and 1919, additional roads were constructed on the land adjacent to the site. In 1948, more of the Little Creek Base was constructed and the waterway (present day project site location) was reclaimed. Between 1954 and 1964, the maps show that Murray Road to the south of the project site was extended. Between 1990 and 2003, the existing building on the site was constructed. Between 2004 and 2005, the adjacent parking lot was constructed.

Boat Canopy:

Overall the maps and images illustrate that the site is located directly adjacent to a previously reclaimed area and may have contained infrastructure that has since been demolished.

This project site location appears to be adjacent to reclaimed land. Between 1918 and 1964, additional roads were constructed in the land adjacent to the site. Between 1964 and 1990, several buildings were constructed adjacent to the project site, including the building directly to the south. Between 2018 and 2019, the building directly to the west of the project site was built.

The site is currently an asphalt parking lot.

Vehicle Maintenance and Boat Shop:

Overall the maps and images illustrate that the site contained buildings that have since been demolished. In particular, a coal/steam heating plant was present at the boat shop location but was demolished in 2010. The site does not appear to be located within a previously reclaimed area.

This project site location does not appear to be within the limits of reclaimed land. Between 1918 and 1919, additional roads were constructed in the land adjacent to the site. In 1948, more of the Little Creek Base was constructed, and the project site was partially developed with buildings and roadways. Between 1954 and 1964, the maps show that some of the buildings occupying the southwestern portion of the site were demolished and others were built. In northeastern portion of the site, Murray Road was extended. Before 1990, a steam plant and a coal storage yard/lagoon were built in the northeastern portion of the site. Both were subsequently demolished in 2011 and replaced by an open grassy field. In the southwestern portion of the site, between 1990 and 2002, the two adjacent buildings were constructed.

A section of the 1918 United States Geological Survey topographic map of Cape Henry is presented in Figure 2.

Figure 2: United States Geological Survey Reclamation Map

Source: United States Geological Survey (Ocean View Quadrangle, 1918)

RED – Parking Lot; ORANGE – Armory Addition; GREEN – Ordnance Operations;

BLUE – Boat Canopy; PURPLE – Vehicle Maintenance and Boat Shop

2.0 FIELD AND LABORATORY PROCEDURES

2.1 Field Exploration

In order to explore the general subsurface soil types and to aid in developing associated foundation design parameters, the following exploration program was performed:

Parking Lot:

• Two (2) 10-foot deep Standard Penetration Test (SPT) borings (designated as B-1 and B-2) were drilled within the existing pavement areas.

• One (1) 10-foot deep SPT boring (designated as BMP-1) was drilled within the proposed BMP area.

• One (1) 74.5-foot deep Cone Penetration Test (CPT) probe (designated as CPT-1) was advanced within the proposed armory addition’s footprint. This boring reached refusal before its intended depth of 100 feet.

Parking Lot Boat Canopy

Armory Addition

Vehicle Maintenance and Boat Shop Ordnance

Operation

• One (1) 80-foot deep SPT boring (designated as B-3) was drilled within the proposed armory addition’s footprint.

• One (1) 10-foot deep SPT boring (designated as B-4) was drilled within the proposed pavement area.

• One (1) bulk soil sample for California Bearing Ratio (CBR) testing was collected from boring location B-4 using coring and a manual (hand-dug) excavation.

• One (1) 60-foot deep SPT boring (designated as B-5) was drilled within the proposed ordnance operations structure’s footprint.

• One (1) 10-foot deep SPT boring (designated as B-6) was drilled within the proposed pavement area.

• One (1) bulk soil sample for CBR testing was collected from boring location B-6 using a manual (hand-dug) excavation.

• One (1) 90-foot deep SPT boring (designated as B-13) was drilled within the proposed boat canopy’s footprint.

Vehicle Maintenance and Boat Shop:

• One (1) 80-foot deep SPT boring (designated as B-7) was drilled within the proposed vehicle maintenance facility’s footprint.

• One (1) Shelby Tube was collected from boring B-7A between the depths of 7 and 9 feet below surface grade. The sample was damaged and not suitable for consolidation testing. GET remobilized to the site at a later date, another Shelby Tube sample was obtained at the same depth from boring B-7B, and the sample was fully recovered.

Both B-7A and B-7B were offset within 8 feet of the original B-7 borehole.

• One (1) 80-foot deep SPT boring (designated as B-8) was drilled within the proposed boat shop’s footprint.

• One (1) Shelby Tube was collected from boring B-8A between depths of 10 and 12 feet below surface grade; however, the pilot hole appeared to have been offset into an abandoned utility trench. The tube was split vertically between clay and gravel. GET remobilized to the site at a later date and another Shelby Tube sample was obtained at the same depth at offset location B-8B. Both B-8A and B-8B were offset within 8 feet of the original B-8 borehole.

• One (1) 101.6-foot deep CPT probe (designated as CPT-2) was advanced within the proposed structure’s footprint. Down-hole shear wave velocity (Vs) measurements were performed at 1-meter intervals to the termination depth.

• Three (3) 10-foot deep SPT borings (designated as B-9, B-10, and B-12) were drilled within the proposed pavement areas.

• One (1) bulk soil sample for CBR testing was collected from boring location B-9 using a manual (hand-dug) excavation.

• One (1) 20-foot deep SPT boring (designated as B-11) was drilled within the proposed wash pad area.

• One (1) bulk soil sample for CBR testing was collected from boring location B-11 using a manual (hand-dug) excavation.

• Three (3) 10-foot deep SPT borings (designated as BMP-2, BMP-3, and BMP-4) were drilled within proposed BMP areas. Additionally, two (2) temporary groundwater monitoring wells were installed at locations BMP-2 and BMP-4.

• Two (2) infiltration tests were performed at boring locations BMP-2 and BMP-4. The infiltration test at BMP-2 was run at a depth of 2 feet above the estimated seasonal high water table (ESHWT). The infiltration test at BMP-4 was run at a depth of 2 feet above the stabilized groundwater table (as specified by the client). The testing was not run at 2 feet above the ESHWT at BMP-4 given the shallow nature of the stabilized groundwater table.

• Three (3) composite soil samples were created from boring locations in the immediate vicinity of B-8, BMP-2, and BMP-4 for the purpose of construction and disposal related characterization of the site soils and for information on soil corrosiveness and aggressiveness potential. The samples were obtained from the SPT boring holes and then using hand augers directly adjacent (within 2 feet) to obtain more material. The sampling equipment was cleaned and decontaminated using non-phosphate industrial grade detergent and a distilled water rinse prior to collecting and compositing each sample. The resultant composite soil sample was placed in appropriately preserved certified clean glass containers, labeled, packed on ice and delivered to the contract laboratory under chain-of-custody protocol to a National Environmental Laboratory Program (NELAP) accredited laboratory.

The SPT borings were performed with the use of rotary wash “mud” drilling procedures in general accordance with ASTM D 1586. The tests were performed continuously from the existing ground surface to depths of 10 and 12-feet, and at 5-foot intervals thereafter starting at a depth of 13-feet. The soil samples were obtained with a standard 1.4” I.D., 2” O.D., 30” long split-spoon sampler. The sampler was driven with blows of a 140 lb. hammer falling 30 inches, using an automatic hammer. The number of blows required to drive the sampler each 6-inch increment of penetration was recorded and is shown on the boring logs. The sum of the second and third penetration increments is termed the SPT N-value (uncorrected for automatic hammer).

A representative portion of each disturbed split-spoon sample was collected with each SPT, placed in a glass jar, sealed, labeled, and returned to our laboratory for review. All soil boring and sampling operations (excluding in-situ testing) were monitored and logged on-site on a full time basis by an appropriately trained geotechnical engineer’s representative. All boreholes that penetrated the groundwater table were backfilled upon completion with the drilling spoils mixed with a cement-bentonite grout mix. CBR excavations were backfilled with soil cuttings/imported clean fill material that was compacted to prevent future settlement or subsidence.

The monitoring wells were installed using 5.25 I.D. hollow stem auger and constructed of 2-inch diameter, Schedule 40 PVC materials. A section of 0.010-inch slotted screen was placed in each borehole with casing threaded to the top. An appropriately graded sand/gravel pack was placed around each screen and extended one to two feet above the top of the screen. A one to two foot bentonite seal was then placed above each sand/gravel pack and hydrated with potable water. The remainder of each borehole annular space was pumped full of a neat cement grout.

Four (4) relatively undisturbed, 3-inch diameter, thin-walled Shelby tube samples were collected from the boring locations at depths identified in Table I. The Shelby tube samples were obtained by hydraulically pressing a 3-inch outside diameter Shelby tube into the targeted soils using the drill rig. The tubes were sealed in general accordance with ASTM standards and returned to G E T Solutions, Inc.’s Virginia Beach laboratory for extraction, classification, and consolidation testing (ASTM D 2435).

Table I – Schedule of Collected Shelby Tube Samples

Boring ID Depth of Shelby Tube Sample

B-7A 7-9 feet below grade B-8A 10-12 feet below grade B-7B 7-9 feet below grade B-8B 10-12 feet below grade

The cone penetration tests (CPTs) were advanced and performed by ConeTec, Inc. personnel.

The CPTs are conducted using an integrated electronic piezocone penetrometer and a data acquisition system. The piezocone penetrometers are compression type designs in which the tip and friction sleeve load cells are independent and have separate load capacities. The piezocones use strain gauge load cells for tip and sleeve friction and a strain gauge diaphragm type transducer for recording pore pressure.

The boring locations were established by the client and G E T Solutions Inc. and were approved by NAVFAC on October 15, 2019. The boring locations were staked in the field by a representative of G E T Solutions, Inc. with a hand held GPS device and by corroborating the location with easily identifiable landmarks. The borings were denoted with their respective boring name using spray paint and flagged wooden stakes. The site specific boring plans are attached in Appendix I.

2.2 Field and Laboratory Testing

Soil testing provided by G E T Solutions, Inc. was performed in accordance with American Society for Testing and Materials (ASTM) standards. All soils and materials tests were performed in our AASHTO re:source (formally AMRL) and US Army Corps of Engineers certified Virginia Beach laboratory.

2.2.1 Soil Classification and Index Testing

Representative portions of all soil samples collected during drilling operations were labeled, preserved and transferred to our laboratory in accordance with ASTM D4220 for classification and analysis. Soil descriptions on the boring logs are provided using visual-manual methods in general accordance with ASTM D2488 using the Unified Soil Classification System (USCS).

Soil samples that were selected for index testing were classified in general accordance with ASTM D2487. It should be noted that some variation can be expected between samples classified using the visual-manual procedure (ASTM D2488) and the USCS (ASTM D2487). A summary of the soil classification system is provided in Appendix II.

Representative split-spoon soil samples were selected and subjected to natural moisture, #200 sieve wash, full sieve testing, and Atterberg Limits testing in order to corroborate the visual classification. These test results are presented in Appendix III and on the soil test boring logs provided in Appendix IV. Generalized subsurface soil profiles are provided in Appendix V. Core logs are provided in Appendix VI. The comprehensive results of the CPT and DMT tests are presented in Appendix VII.

2.2.2 Bulk Soil Sample Testing

The bulk soil samples were returned to our AASHTO re:source certified Virginia Beach laboratory and subjected to Standard Proctor and CBR testing, in accordance with ASTM D698 and ASTM D1883 respectively, and the NAVFAC provided SAES. The CBR samples were prepared to wet of optimum and compacted to between 90 and 95 percent Standard Proctor dry density (ASTM D698). A surcharge of 10 pounds was used. The stress-strain curve was plotted for each specimen. If necessary, the stress-strain curves were corrected by adjusting the locations of the origin for concave shaped curve. Subsequently, the CBR values were selected at 0.1-inch penetration using the corrected load values. A summary of the CBR test results is presented in Table II and the Proctor Curves, Particle Size Distribution Reports, and the CBR curves are provided in Appendix VIII.

Table II – CBR Test Results

Boring

ID

Depth Below Grade

(ft)

USCS wN(1)

Passing #200

Sieve (%)

Atterberg Limits

(LL/PL/PI)

Max.

Dry

Density (pcf)

Optimum Moisture

CBR

Value

Swell

B-4 1 to 3 CL 15 79.9 22/11/11 122.9 10.0 4.1 0.6

B-6 1 to 3 SM 8 17.2 NP 116.3 10.8 6.9 0.0

B-9 1 to 3 CL 20 69.3 34/20/14 106.4 16.4 7.4 0.2

B-11 1 to 3 SP 8 3.2 NP 105.7 14.4 14.0 0.0

Note(s): (1) wN – Natural Moisture Content

2.2.3 In-Situ Permeability Testing

Infiltration testing, using a constant-head borehole permeameter, was performed at depths ranging from 2.76 to 3.67 feet below existing grades (BMP-2 and BMP-4 respectively). The infiltration test at BMP-2 was run at a depth of 2 feet above the ESHWT. The infiltration test at BMP-4 was run at a depth of 2 feet above the stabilized groundwater table (as specified by the client). This modification was made as two feet above the estimated seasonal high water table was deemed too shallow. The ESHWT is provided Section 3.2 of this report.

The boreholes were prepared utilizing a planar auger to remove soil clippings from the base.

Permeability testing was then conducted within the vadose zone utilizing an Aardvark PermeameterTM and the following testing procedures on the following page:

An adjustable-height table was assembled and placed adjacent to the boreholes. The table was leveled at a height to provide the proper amount of overhead pressure for shallow measurements. The table holds a digital scale accurate to 0.01g upon which rests a water reservoir. A supported flexible pipe of an appropriate length so as not to induce a weight upon the reservoir served as a conduit to the Aardvark Permeameter Module (APM). The APM establishes a constant water head within the borehole during testing by use of a precision valve and float assembly. The APM was supported by a calibrated tape measure and lowered into the borehole to the test depth elevation. As required by the Glover solution, the APM was suspended above the bottom of the borehole at the height that establishes a water level approximately 5 times the borehole radius.

Testing began as the shut-off valve was opened allowing water to pass through the APM to fill the borehole to the constant water level elevation. The absorption rate slowed as the soil voids became filled and an equilibrium developed as a wetting bulb developed around the borehole.

Water was added to the reservoir as needed. As the water drained into the borehole and surrounding soils during testing, the water level within the reservoir was recorded by weight at a regular time interval. The test was continued until relatively consistent flow rates were documented. During testing the quick release connections and shutoff valve were monitored to ensure that no leakage occurred. The flow rate (Q), height of the constant water level (H), and borehole diameter (D) were used to calculate Ks utilizing the Glover Solution.

Based on the field testing, the hydraulic conductivities of the soils are presented in Table III.

The comprehensive hydraulic conductivity worksheets are provided in Appendix IX.

Table III – Constant Head Borehole Permeameter Test Results

Boring ID Test Depth

(ft) (1)

Ksat Value (in/hr)

Ksat Value (cm/sec) Ksat Class USCS

Classification

BMP-2 2.76 .348 2.46x10-4 Moderately

High

SM

BMP-4 3.67 .011 7.98x10-6 Low CH

Note(s): (1) Test depth refers to depth below the existing grade at the test location.

The permeability test results provided in this report are the result of permeability testing at the locations and depths indicated. Variability in site conditions such as wind can affect the accuracy of the results. Varying site conditions, including soil composition, soil density, stratum depth, and stratum thickness should be expected throughout the site. As such, the permeability test results should not be assumed for all locations and depths across the project site.

2.2.4 Consolidation Testing

Two (2) one-dimensional consolidation tests were performed at our Virginia Beach laboratory in general accordance with ASTM D 2435 on the specimens extracted from the Shelby tube samples obtained at boring locations B-7 from 7 to 9 feet and B-8 from 10 to 12 feet. More detailed information is provided in the “Shelby Tube Classification” presented in Appendix X. A representative specimen from each of the Shelby tubes was also subjected to natural moisture content, Atterberg Limits, and -#200 sieve testing. The consolidation curves are provided in Appendix XI.

2.2.5 Chemical Analysis

Three (3) composite soil samples (designated as B-8, BMP-2, and BMP-4) were created from 1 to 4 feet below surface grades from within and in the immediate vicinity of their respective borings. They were collected for the purpose of construction and disposal related characterization of the site soils and for information on soil corrosiveness and aggressiveness potential. The samples were obtained from their respective SPT boring holes and then using hand augers directly adjacent (within 3 feet) to obtain more material. The resultant composite soil samples were delivered to the contract laboratory under chain-of-custody protocol for analysis for the presence and concentrations of the following analytes: pH, moisture content, soluble sulfates, chlorides, electrical resistivity, redox potential, and sulfides.

A summary of the corrosivity and aggressiveness laboratory testing results is presented in Table

III.

Table IV - Summary of Corrosivity Test Results

Sample Location

Depth (feet below existing grade) pH(1) (Std.

Units)

Percent Moisture

Redox Potential(2)

(mV)

Resistivity(3) (ohms-cm)

Chloride(4) (mg/Kg)

Sulfate(5) (mg/Kg)

Sulfide(6) (mg/Kg)

B-8 1-4 8.1 20.1 -130.8 8160 ND ND ND

BMP-2 1-4 7 15.0 83.4 7890 ND 86.6 ND

BMP-4 1-4 6.9 13.9 87.7 4560 ND 269 ND

(1) – Method 9045D

(2) – Method 2580

(3) – Method 120.1

(4) – Method 9056

(5) – Method 9056

(6) – Method 4500-S2D-2011 ND – Not Detectable above the laboratory’s Method Detection Limit

An evaluation of the soil analytical data submitted from borings BMP-2, BMP-4, and B-8 at depths of 1.0-4.0 feet below surface grade shows that the submitted soil samples do not appear to be corrosive to ductile iron pipe or ferrous materials when compared to the AWWA-DIPRA 10 Point Evaluation Method.

Additionally, the following chemical environmental analyses were performed on the three composite samples from B-8, BMP-2, and BMP-4 in accordance with the appropriate EPA SW- 846 method: ignitability, corrosivity, reactivity, TCLP (8 RCRA metals, volatiles, semi-volatiles, PCBs, pesticides, and herbicides), BTEX, TOX, Paint Filter and TPH (DRO & GRO).

An evaluation of the soil analytical data submitted from borings BMP-2, BMP-4, and B-8 at depths of 1.0-4.0 feet below surface grade shows that the submitted soil samples did not produce detectable concentrations for the analytes except in the case of Barium in boring BMP- 2 and B-8. However, the Barium levels are far below the regulatory limit of 100 mg/L.

A summary of the construction and disposal related laboratory testing results is presented in Table V. The comprehensive laboratory analytical results are provided in Appendix XII.

February 21, 2020 ervice Support Facilities Creek-Fort Story, Virginia Beach, Virginia

Table V - Summary of Soil Environmental Analytical Results

LP-RCRA-

Metals Volatiles Semi-volatiles PCBs Pesticides Herbicides BTEX EOX Paint

Filter

TPH-

DRO/GRO

hod 1311- 000/7000 Series

EPA

8760D EPA 8260A EPA

8082A

EPA

8081B

EPA

8151A Method 8260B

EPA

EPA

9095B

Method 8015C

(mg/L) (μg/L) (μg/L) (μg/L) (μg/L) (mg/L) (μg/Kg) (mg/Kg) --- (mg/Kg)

ND

ND ND ND ND ND ND ND Pass ND xcept for um = 0.33 mg/L

ND

ND ND ND ND ND ND ND Pass ND xcept for um = 0.36 mg/L

ND ND ND ND ND ND ND ND Pass ND d Above Laboratory’s Method Detection Limits m or parts per million parts per million m or parts per billion

3.0 SITE AND SUBSURFACE CONDITIONS

3.1 Subsurface Soil Conditions

Parking Lot:

The results of our field exploration program indicated the presence of 9.5 inches of concrete and 3 inches of aggregate base at boring B-1, 5 inches of asphalt and 3 inches of aggregate base at boring B-2, and 3 inches of topsoil at boring BMP-1. Based on the full extent of the field investigations, it is concluded that the initial stratum consists of a layer of granular fill soils extending to depths of approximately 4 to 7.5 feet below surface grade. Underlying the surficial materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 2-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SM, SP-SM), extending to depths of approximately 4 to 7.5 feet below surface grade. The Standard Penetration Test (SPT) N-value (which are uncorrected for hammer efficiency (N(60)) and overburden (N(160))) recorded within these soils ranged from 2 to 19 blows-per-foot, indicating a very loose to medium dense relative density.

Stratum I: Underlying the granular fill soil layer, a deposit of CLAY (CH) was noted, extending to a depth of approximately 8 to 10 feet below existing grade (and the exploration termination depths of B-1 and B-2). The N-values recorded within these soils ranged from 1 to 5 blows-per-foot, indicating a very soft to medium stiff relative density.

Stratum II: Underlying the cohesive soil layer, a deposit of very loose granular soils was noted, extending to the exploration termination depth of 10 feet below existing grade in boring BMP-1. The N-values recorded within these soils consisted of 1 blow-per-foot, indicating a very loose relative density.

The results of our field exploration program indicated the presence of 8 to 8.5 inches of concrete and 3 inches of aggregate base at borings B-3 and CPT-1. At boring location B-4, 2 inches of asphalt, 3 inches of cemented soil, and 3 inches of aggregate base were recovered. The results of our field exploration program also indicated the presence of 2 to 6 feet of fill material that included gravel and brick fragments. Underlying the fill materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 3-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SM, SP-SM) and CLAY

(CL), extending to depths of approximately 2 to 6 feet below surface grade. The N-values recorded within the cohesive soils of this layer ranged from 7 to 32 blows-per-foot, indicating a medium stiff to hard relative density. The N-values recorded within the granular soils of this layer ranged from 10 to 32 blows-per-foot, indicating a loose to dense relative density.

Stratum I: The first natural soil layer extended to a depth of approximately 10 feet below the existing site grades at borings B-3 and CPT-1 and to the boring termination depths of B-4 (10 feet). The recovered soils were comprised of interbedded layers of Sand (SC, SP, SM) and Clay (CL, CH). The N-values recorded within these granular soils ranged from 6 to 13 blows-per-foot, indicating a loose to medium dense relative density. The N-values recorded within these cohesive soils ranged from 4 to 6, indicating a soft to medium stiff consistency.

Stratum II: The second soil layer extended to a depth of approximately 60 feet below the existing site grades at borings B-3 and CPT-1. The recovered soils were comprised of SAND (SC, SP, SM, SP-SM) with varying amounts of Clay and Silt.

The N-value recorded within these granular soils ranged from 2 to 33 blows-per-foot, indicating a very loose to dense relative density. The CPT-1 data indicates layers of Clay from 32 to 38-feet and from 48 to 54-feet below grade surface however these layers were determined to be layers of clayey Sand in boring B-3.

Stratum III: The third and final soil layer extended to a depth of 80 feet below the existing site grades at boring B-3 and to the boring termination depth of CPT-1 (74.5 feet).

The recovered soils were comprised of SAND (SP-SM, SM, SC) with varying amounts of Clay, Silt, and marine shell fragments. The N-values recorded within these soils ranged from 13 to 35 blows-per-foot, indicating a medium dense to dense relative density. These characteristics are indicative of the Yorktown Formation

The results of our field exploration program indicated the presence of 3 inches of topsoil at boring B-5 and 4 inches of aggregate base at boring B-6. Additionally, the private locator discovered what appears to be a concrete slab located in the central eastern portion of the site.

Based on the full extent of the field investigations, it is concluded that the initial stratum consists of a layer of granular fill soils extending to depths of approximately 18.5 feet below surface grade. Boring B-6 terminated in this layer. Underlying the surficial materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 4-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SM, SC, SP-SM, SP), extending to depths of approximately 18.5 feet below surface grade. The N-values recorded within this layer ranged from 2 to 22 blows-per-foot, indicating a very loose to medium dense relative density.

Stratum I: The first natural soil layer underlying the fill soils was a layer of CLAY (CH) soils extending to a depth of approximately 23 feet below existing grade and to the termination depth of B-6 (10 feet). The N-values recorded within these soils consisted of 2 blows-per-foot, indicating a very soft relative density.

Stratum II: The second soil layer extended beneath the first layer to a depth of approximately 42 feet below the existing site grades. The recovered soils were comprised of SAND (SC, SP, SM, SP-SM) with varying amounts of Clay and Silt.

The N-values recorded within these soils consisted of 4 to 19 blows-per-foot, indicating a very loose to medium dense relative density.

Stratum III: The third soil layer extended to a depth of approximately 49 feet below the existing site grades. The recovered soils were comprised of CLAY (CH) with varying amounts of Sand and Silt. The N-value recorded within these soils is 4 to 13 blows-per-foot, indicating a soft to stiff relative density.

Stratum IV: The fourth and final soil layer extended to the boring B-5 termination depth of approximately 60 feet below the existing site grades. The recovered soils were comprised of SAND (SC, SP, SM, SP-SM) with varying amounts of Clay and Silt.

The N-values recorded within these soils consisted of 13 to 27 blows-per-foot (BFP), indicating a medium dense relative density.

The results of our field exploration program indicated the presence of 8 inches of concrete and 3 inches of aggregate base at boring B-13. The results of our field exploration program also indicated the presence of 12.5 feet of fill material that included gravel and wood fragments.

Underlying the fill materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 5-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SM, SP), extending to depths of approximately 12.5 feet below surface grade. The N-values recorded within this layer ranged from 9 to 15 blows-per-foot, indicating a loose to medium dense relative density.

Stratum I: The first natural soil layer underlying the granular fill soil was a layer of CLAY

(CH) soils extending to a depth of approximately 21.5 feet below existing grade.

The N-values recorded within these soils ranged from 0 to 2 blows-per-foot, indicating a very soft relative density.

Stratum II: The second soil layer extended beneath the first layer to a depth of approximately 36.5 feet below the existing site grades. The recovered soils were comprised of SAND (SC, SM) with varying amounts of Clay and Silt. The N-value recorded within these granular soils ranged from 4 to 17 blows-per-foot, Stratum III: The third soil layer extended below the second layer to a depth of 64.5 feet below the existing site grades. The recovered soils were comprised of CLAY (CH) with varying amounts of Sand, Silt, and marine shell fragments. The N-values recorded within these soils ranged from 2 to 21 blows-per-foot, indicating a very soft to very stiff relative density. Based on the historical information provided by NAVFAC in this area, we would expect the Yorktown Formation to be encountered around 60 to 70 feet below grade surface.

Stratum IV: The fourth soil layer extended to a depth of approximately 82 feet below the existing site grades. The recovered soils were comprised of SAND (SC, SP, SM) with varying amounts of Clay, Silt and marine shell fragments. The N-values recorded within these soils consisted of 4 to 21 blows-per-foot, indicating a very loose to medium dense relative density.

Stratum V: The fifth and final soil layer extended to the boring B-13 termination depth of approximately 90 feet below the existing site grades. The recovered soils were comprised of SAND (SC, SP, SM) with varying amounts of Clay, Silt and marine shell fragments. The N-values recorded within these soils consisted of 14 to 16 blows-per-foot, indicating a medium dense relative density. These characteristics are indicative of the Yorktown Formation.

Boat Shop:

The results of our field exploration program indicated the presence of 3 to 4 inches of topsoil at borings B-8, B-11, B-12, and BMP-4. The results of our field exploration program also indicated the presence of 2.5 to 7 feet of fill material that included gravel, marine shell fragments, cemented soil fragments, plastic, and organics. Underlying the surficial materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 4-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SM, SC, SP), extending to depths of approximately 2.5 to 7 feet below surface grade. The N-values recorded within this layer ranged from 2 to 20 blows-per-foot, indicating a very loose to medium dense relative density.

Stratum I: The first natural soil layer extended to a depth of approximately 12 feet below the existing site grades at all borings and to the boring termination depths of B-10, B- 12, and BMP-4 (10 feet). The recovered soils were comprised of interbedded layers of SAND (SC, SP, SM) and CLAY (CL, CH). The N-values recorded within these granular soils ranged from 0 to 8 blows-per-foot, indicating a very loose to loose relative density. The N-values recorded within these cohesive soils ranged from 0 to 6, indicating a very soft to medium stiff consistency.

Stratum II: The second soil layer extended to a depth of 52 feet below the existing site grades and to the termination depth of B-11 (20 feet). The recovered soils appear to be comprised of SAND (SC, SM, SP-SM) with varying amounts of Clay and Silt. The N-value recorded within these soils ranged from 2 to 12 blows-per-foot, Stratum III: The third soil layer extended below the second layer to a depth of 57 feet below the existing site grades. The recovered soils were comprised of CLAY (CH) with varying amounts of Sand, Silt, and wood fragments. The N-value recorded within these soils consisted of 8 blows-per-foot, indicating a medium stiff relative density.

Stratum IV: The fourth and final soil layer extended to a depth of 80 feet below the existing site grades at borings and to the boring termination depth of B-8 (80 feet). The recovered soils appear to be comprised of SAND (SC, SM) with varying amounts of Clay and Silt. The N-value recorded within these soils ranged from 7 to 31 blows-per-foot (BFP), indicating a loose to dense relative density. Based on the historical information provided by NAVFAC in this area, we would expect the Yorktown Formation to be encountered around 60 to 70 feet below grade surface.

Vehicle Maintenance Facility (Northern Portion):

The results of our field exploration program indicated the presence of 2.5 to 4 inches of topsoil at borings B-7, B-10, and B-11. The results of our field exploration program also indicated the presence of 2.5 to 7 feet of fill material that included marine shell fragments. Underlying the topsoil materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 2-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SP-SM, SC, SP), extending to depths of approximately 2.5 to 7 feet below surface grade. The N-values recorded within this layer ranged from 2 to 8 blows-per-foot, indicating a very loose to loose relative density.

Stratum I: The first natural soil layer extended to a depth of approximately 12 feet below the existing site grades at all borings and to the boring termination depth of B-10 (10 feet). The recovered soils were comprised of interbedded layers of SAND (SC, SP, SM) and CLAY (CL, CH). The N-values recorded within these granular soils ranged from 0 to 8 blows-per-foot, indicating a very loose to loose relative density. The N-values recorded within these cohesive soils ranged from 0 to 6, indicating a very soft to medium stiff consistency.

Stratum II: The second and final soil layer extended to a depth of 80 feet below the existing site grades at borings and to the boring termination depths of B-11 (20 feet) and B-7 (80 feet). The recovered soils appear to be comprised of SAND (SC, SM, SP, SP-SM) with varying amounts of Clay and Silt. The N-values recorded within these soils ranged from 2 to 38 blows-per-foot (BFP), indicating a very loose to dense relative density. Based on the historical information provided by NAVFAC in this area, we would expect the Yorktown Formation to be encountered around 60 to 70 feet below grade surface.

Vehicle Maintenance Facility (Southern Portion):

The results of our field exploration program indicated the presence of 2 to 4 inches of topsoil at borings B-9, BMP-2, and BMP-3. The results of our field exploration program also indicated the presence of 0 to 3 feet of fill material that included marine shell fragments and organics.

Underlying the topsoil materials and extending to the boring termination depths, the subsurface soils were generally arranged in a 6-layer configuration.

Fill Material: The first layer encountered consisted of fill soils, SAND (SP-SM) and CLAY

(CL), extending to depths of approximately 0 to 3 feet below surface grade. The N-value recorded within the cohesive soils of this layer was 6 blows-per-foot, indicating a medium stiff to hard relative density. The N-values recorded within the granular soils of this layer ranged from 2 to 4 blows-per-foot, indicating a very loose to loose relative density.

Stratum I: The first natural soil layer extended to a depth of approximately 10 feet below the existing site grades at all borings and to the boring termination depths of B-9, BMP-2, and BMP-3 (10 feet). The recovered soils were comprised of interbedded layers of SAND (SC, SM) and CLAY (CL, CH).