Geotechnical Engineering Report.pdf

Geotechnical Engineering Report

FY’19 Lab Replacement Program (LRP) Naval Air Station Patuxent River, Maryland

May 27, 2020

19955 Highland Vista Drive, Suite 170 Ashburn, Virginia 20147 703-726-8030

19955 Highland Vista Dr., Suite 170 Ashburn, Virginia 20147

(703) 726-8030 www.geoconcepts-eng.com

May 27, 2020

Ms. Abbe I. Little, AIA Wiley|Wilson 6800 Paragon Place, Suite 600 Richmond, Virginia 23230

Subject: Geotechnical Engineering Report FY ’19 Lab Replacement Program (LRP) (Our JD185314) Naval Air Station, Patuxent River, Maryland

Dear Ms. Little:

GeoConcepts Engineering, Inc. (GeoConcepts) is pleased to present the following geotechnical engineering report prepared for FY ’19 Lab Replacement Program at the Naval Air Station in Patuxent River, Maryland.

We appreciate the opportunity to serve as your geotechnical consultant on this project. Please do not hesitate to contact me if you have any questions or want to meet to discuss the findings and recommendations contained in the report.

Sincerely, GEOCONCEPTS ENGINEERING, INC.

Katherine N. Fordney, PE Project Engineer Katherine.Fordney@Terracon.com

Table of Contents

1.0 Scope of Services

2.0 Site Description and Proposed Construction

3.0 Subsurface Conditions

3.1 Geology

3.2 Stratification

3.3 Groundwater

3.4 Soil Laboratory Test Results

3.5 Seismic Site Classification

3.6 Metal Corrosion/Concrete Attack Test Results

4.0 Engineering Analysis

4.1 Soil Design Parameters

4.2 Foundations

4.2.1 Spread Footings

4.2.2 Pre-Consolidation Program for Spread Footing Foundation Option – IDS Building

4.3 Finished Floor Slabs on Grade

4.4 Pavements

4.5 Earthwork

5.0 General Limitations

Figure 1: Geology Map Figure 2: Settlement Plate Plan and Detail Figure 3: Compacted Structural Fill Diagram

Appendix A: Subsurface Investigation Appendix B: Soil Laboratory Test Results Appendix C: Engineering Calculations

May 27, 2020 JD185314 Page 1

1.0 Scope of Services

This geotechnical engineering report presents the results of the field investigation, soil laboratory testing, and engineering analysis of the geotechnical data. This report specifically addresses the following:

· An evaluation of subsurface conditions within the area of the proposed site development, including seismic site classifications per the International Building Code.

· Foundation recommendations for support of the proposed buildings and lower floor slabs on grade, including soil design parameters.

· An assessment of subgrade conditions for support of flexible and rigid pavements, including an estimated design California Bearing Ratio (CBR) value based on soil laboratory classification test results.

· Earthwork recommendations for construction of loadbearing fills, including an assessment of on-site soils to be excavated for re-use as fill.

Services not specifically identified in the contract for this project are not included in the scope of services.

2.0 Site Description and Proposed Construction

This project consists of development at two separate sites at the Naval Air Station (NAS), Patuxent River Maryland. The first site, AMSI Lab (AD 5.4.3), is located on the northern side of the base. Specifically, the AMSI Lab site is located at the existing Building 2109 off Switzer Road. The elevation at this site ranges from approximately elevation (EL) 19 to EL 20, sloping downwards to the northeast. The proposed construction consists of an addition to the existing building. Based on plans provided to us dated August 8, 2019, we understand that the proposed construction is approximately 13,000 GSF and that finished floor elevation will be at approximately EL 19.5 with no basements. We also understand maximum column loads are approximately 80 kips, and maximum wall loads are approximately 3.9 kips/LF.

AMSI Site Layout Plan provided by Wiley|Wilson dated August 2019.

May 27, 2020 JD185314 Page 2

The second site, IDS Lab Consolidation (AD 4.11.2), is located at the southwest sector of Webster Outlying Field. This site currently consists of a relatively flat, grassy field at approximately EL 7. The field is bordered to the southwest by the St. Mary’s River. We understand that the proposed construction will be approximately 15,000 GSF and that finished floor elevation will be at approximately EL 10.5 with no basements. Therefore, about 3.5 feet of new fill/slab will be placed at the site to achieve the finished floor elevation. We also understand maximum column loads are approximately 60 kips.

IDS Site Layout Plan provided by Wiley|Wilson dated August 2019.

3.0 Subsurface Conditions

Subsurface conditions were investigated by drilling a total of two Standard Penetration Test (SPT) borings in the proposed AMSI Lab site and six SPT borings in the proposed IDS Lab site. The SPT borings were completed by Connelly and Associates, Inc. of Frederick, Maryland under our observation between June 24 and July 18, 2019, utilizing mud rotary method with automatic hammer. The sampler was advanced by driving the spoon into undisturbed soil under the impact of a 140-lbf hammer free-falling from 30 inches height per ASTM D1586-11. Test boring logs and boring location plans are presented in Appendix A of this report.

3.1 Geology

The site is located within the Coastal Plain Physiographic Province of Maryland. The Coastal Plain consists of a seaward thickening wedge of unconsolidated to semi-consolidated sedimentary deposits from the Cretaceous Geologic Period to the Holocene Geologic Epoch. These deposits represent marginal-marine to marine sediments consisting of interbedded sands and clays. The Coastal Plain is bordered to the east by the Atlantic Ocean and to the west by the Piedmont Physiographic Province. The dividing line between the Coastal Plain and the Piedmont is locally referred to as the “Fall Line”. This name comes from the waterfalls that form as a result of the differential erosion that occurs as streams cross the Piedmont/Coastal Plain contact.

Specifically, the native soils are alluvial soils of the Maryland Point Formation, historically referred to as the Lowland Deposits. The Lowland Deposits are underlain by sediments of the Chesapeake Group. The Chesapeake Group consist of (from youngest to oldest) the St. Marys Formation, Choptank Formation, and

May 27, 2020 JD185314 Page 3

Calvert Formation, all of Miocene geological age. At the subject site, the strata immediately underlying the Maryland Point Formation compare favorably with the gray, sandy clays of the St. Marys Formation, and the gray, silty and clayey sands of the Choptank Formation, respectively. The Choptank Formation contains prominent shell beds with calcareous soils. A geology map is presented as Figure 1 at the end of this report.

3.2 Stratification

The subsurface materials encountered have been stratified for purposes of our discussions herein. These stratum designations do not imply that the materials encountered are continuous across the site. Stratum designations have been established to characterize similar subsurface conditions based on material gradations and parent geology. The generalized subsurface materials encountered in the test borings completed at the site have been assigned to the following strata:

Stratum A (Existing Fill) medium dense to dense or stiff to very stiff, SILTY SAND, CLAYEY SAND WITH GRAVEL, FAT CLAY, FILL , moist, orange, brown, gray

Stratum B1 (Lowland Deposits) generally firm to stiff, SANDY FAT CLAY (CH), SILT WITH SAND (ML), moist, light gray, brown, orange

Stratum B2 (Lowland Deposits) medium dense to very dense, SILTY SAND (SM) WITH GRAVEL, CLAYEY SAND (SC), POORLY GRADED SAND (SP), moist, gray, brown, orange

Stratum C1 (St. Marys Formation) very soft to firm, ELASTIC SILT (MH), SANDY FAT CLAY (CH), LEAN CLAY (CL), moist, gray

Stratum C2 (St. Marys Formation) loose to medium dense, POORLY GRADED SAND (SP), CLAYEY SAND (SC), SILTY SAND WITH GRAVEL (SM), moist, gray, black

Stratum D1 (Choptank Formation) generally stiff to very stiff, SANDY SILT (ML), SILTY CLAY (ML- CL), SANDY LEAN CLAY (CL), contains shells, moist, gray

Stratum D2 (Choptank Formation) generally medium dense to very dense, SILTY SAND (SM) WITH

GRAVEL, CLAYEY SAND (SC), POORLY GRADED SAND (SP),

contains shells, moist to wet, gray

Two estimated subsurface diagrams A-A’ to B-B’ have been prepared that illustrate the subsurface conditions indicated by the test borings. The subsurface diagrams are presented in Appendix A, with the locations presented on Figures 3 and 4 in Appendix A.

The two letter designations included in the strata descriptions presented above and on the test boring logs represent the Unified Soil Classification System (USCS) group symbol and group name for the samples based on laboratory testing per ASTM D2487 and visual classifications per ASTM D2488. It should be noted that visual classifications per ASTM D2488 may not match classifications determined by laboratory testing per ASTM D2487.

3.3 Groundwater

Groundwater level observations were made in the field during drilling and up to one day after the completion of the test borings. A summary of the water level readings rounded off to the nearest 0.5 feet elevation is presented below in Table 3.3-1.

May 27, 2020 JD185314 Page 4

Table 3.3-1: Groundwater Readings

Test Boring No. Depth to Groundwater (ft) Groundwater Elevation (ft)

AMSI-1 6.0 EL 12.0

AMSI-2 6.0 EL 13.0

IDS-1 6.0 EL 2.0

IDS-2 10.0 EL -2.0

IDS-3 7.3 EL -0.5

IDS-4 6.0 EL 2.0

IDS-5 10.0 EL -2.0

IDS-6 10.0 EL -3.0

The groundwater observations presented herein are considered to be an indication of the groundwater levels at the dates and times indicated. Where more impervious clay and silt soils are encountered, the amount of water seepage into the borings is limited, and it is generally not possible to establish the location of the groundwater table through short term water level observations. Accordingly, the groundwater information presented herein should be used with caution. Also, fluctuations in groundwater levels should be expected with seasons of the year, construction activity, changes to surface grades, precipitation, or other similar factors.

3.4 Soil Laboratory Test Results

Selected soil samples obtained from the field investigation were tested for grain size distribution, Atterberg limits, and natural moisture contents. A summary of soil laboratory test results is presented below in Table 3.4-1, and the results of natural moisture content tests are presented on the test boring logs in Appendix A.

Table 3.4-1: Summary of Soil Laboratory Test Results

Test Boring

No.

Depth (ft)

Sample Type Stratum Description of Soil

Specimen

Sieve Results

Atterberg Limits Natural

Moisture Content

Percent

Retained #4 Sieve

Percent Passing

#200 Sieve

LL PL PI

AMSI-2 4.0-6.0 Jar A CLAYEY SAND (SC)

WITH GRAVEL 19.2 16.3 24 13 11 12.4

AMSI-2 18.5-20.0 Jar B2 POORLY GRADED

SAND (SP) 0.0 4.8 NP NP NP 30.7

IDS-1 25.0-27.0 Tube C1 LEAN CLAY (CL) 0.0 98.0 34 16 18 28.0

IDS-1 40.0-42.0 Tube D1 LEAN CLAY (CL)

WITH SAND 0.0 79.0 30 20 10 27.7

IDS-2 8.0-10.0 Jar B1 SILT (ML) WITH

SAND 0.0 71.8 19 15 4 12.2

IDS-5 0.0-2.0 Jar A FAT CLAY (CH) 0.6 87.1 56 27 29 35.4

IDS-5 6.0-8.0 Jar B1 SANDY FAT CLAY

(CH) 0.0 68.4 51 25 26 33.6

May 27, 2020 JD185314 Page 5

Test Boring

No.

Depth (ft)

Sample Type Stratum Description of Soil

Specimen

Sieve Results

Atterberg Limits Natural

Moisture Content

Percent

Retained #4 Sieve

Percent Passing

#200 Sieve

LL PL PI

IDS-5 10.0-12.0 Jar C1 SANDY LEAN CLAY

(CL) 0.0 58.7 28 15 13 22.0

IDS-5 23.5-25.0 Jar C1 LEAN CLAY (CL) 0.0 97.3 46 19 27 29.1

IDS-5 38.5-40.0 Jar D1 SILTY CLAY (CL-ML) 0.0 86.6 28 22 6 24.5

IDS-6 6.0-8.0 Jar B1 FAT CLAY (CH) 0.0 88.0 53 25 28 32.1

IDS-6 23.5-25.0 Jar D1 LEAN CLAY (CL) 0.0 89.8 40 18 22 27.3

Notes:

1. Soil tests are in accordance with applicable ASTM standards

2. Soil classification symbols are in accordance with Unified Soil Classification System

3. Visual identification of samples is in accordance with ASTM D2488

4. Key to abbreviations: LL = liquid limit; PL = plastic limit; PI = plasticity index; NP = nonplastic

Results of consolidation tests performed on the Stratum C1 soils are presented below in Table 3.4-2.

Table 3.4-2: Consolidation Test Results Test Boring

No.

Sample

Depth (ft) eO Pc (tsf) Cc Cr

AMSI-1 35.0-37.0 2.3 1.0 0.62 0.10

IDS-1 25.0-27.0 0.67 4.0 0.13 0.02

eO = initial void ratio; Pc = preconsolidation pressure; Cc = compression index; Cr = recompression index.

3.5 Seismic Site Classification

Based on the results of the subsurface investigation and our knowledge of local geologic conditions, the AMSI and IDS site soils have been assigned to a site class E per the International Building Code (IBC).

3.6 Metal Corrosion/Concrete Attack Test Results

In addition to standard geotechnical soil laboratory testing, five samples were submitted to an analytical laboratory for metal corrosion and concrete attack testing. Corrosion testing consisted of analysis for moisture content (EPA), pH (CA-643), resistivity (ASTM G187), sulfides (EPA 376.2), and reduction-oxidation potential (Electrode). The results of these tests are presented below in Table 3.6-1:

Table 3.6-1: Analytical Laboratory Test Results Test

Boring No.

Sample Depth

(ft)

Moisture Content pH Resistivity

(ohm – cm) Sulfides (ppm)

Red-ox Potential

(mV) Point Total

IDS-2 0-5 10 4.6 43000 < 1.2 +31 7

IDS-5 0-5 16 4.6 45000 < 1.2 +23 7

IDS-6 0-5 4.7 5.1 13000 < 1.2 +31 7

AMSI-1 0-5 5.2 7.3 24000 < 1.2 +27 7

May 27, 2020 JD185314 Page 6

Test Boring

No.

Sample Depth

(ft)

Moisture Content pH Resistivity

(ohm – cm) Sulfides (ppm)

Red-ox Potential

(mV) Point Total

AMSI-2 0-5 14 5.8 38000 < 1.2 +21 7

For each test, points are assigned based on the range of the test results. If the total points from the five tests completed for a particular sample are 10 or more, the soil is considered to be corrosive. The methods described herein are based on information from the American Water Works Association (AWWA). Using the methods described by AWWA, the point total for the samples tested averaged 7. Accordingly, the site soils are considered non-corrosive for ductile iron pipes.

Sulfate tests (EPA 375.4) and chloride tests (CA-422) were performed on selected soil samples to determine the severity of sulfate attack on concrete structures. The results of sulfate and chloride testing are presented below in Table 3.6-2.

Table 3.6-2: Sulfate and Chloride Test Results

Test Boring No. Sample Depth (ft)

Sulfate Concentration (ppm)

Chloride Concentration (ppm)

IDS-2 0-5 14 8.0

IDS-5 0-5 11 7.1

IDS-6 0-5 65 8.4

AMSI-1 0-5 39 7.7

AMSI-2 0-5 29 8.1

Based on the results of the sulfate and chloride tests, the severity of concrete attack is calculated to be negligible.

4.0 Engineering Analysis

Recommendations regarding soil design parameters, foundations, finished floor slabs, pavements, and earthwork are presented herein.

4.1 Soil Design Parameters

We recommend and have used the following soil design parameters as presented below in Table 4.1-1 in our analyses:

Table 4.1-1: Soil Design Parameters

Stratum Total Unit

Weight (pcf)

Angle of Internal Friction

(degrees)

Lateral Earth Pressure Coefficients Coefficient of Sliding FrictionActive

(Ka) At-Rest

(Ko) Passive

(Kp)

A 120 30 0.33 0.50 3.00 0.35

B1 115 28 0.36 0.53 2.77 0.30

B2 125 32 0.31 0.47 3.25 0.40

May 27, 2020 JD185314 Page 7

4.2 Foundations

The proposed AMSI and IDS buildings may be supported on spread footings bearing on firm existing soils or new compacted fill. However, the IDS building will require a pre-consolidation program due to the placement of up to 3.5 feet of new fill and floor slab over soft compressible soils. Recommendations regarding spread footings and the pre-consolidation program can be found in the following sections.

4.2.1 Spread Footings

Based on the finished floor elevations for the proposed buildings, generally firm existing fill or new compacted fill should be encountered at proposed spread footing elevations. Spread footings founded in these materials are considered suitable for support of the proposed buildings, and may be designed with a net allowable soil bearing pressure of 2,000 psf. For the IDS building, the spread footings should be installed after the pre-consolidation program as outlined below in Section 4.2.2.

Fill material and compaction requirements are presented in Section 4.5 of this report. Exterior footing subgrades should be located at least 2.5 feet below final exterior grades for frost considerations. Individual column footings and continuous wall footings should be at least 30 inches and 18 inches wide, respectively, for local or punching shear considerations. A maximum slope of one horizontal to one vertical (1H:1V) should be maintained between the bottom edges of adjacent footings.

Footing subgrades should be observed and approved by the Geotechnical Engineer of Record or his/her representative prior to placement of concrete, to ascertain that footings are placed on suitable bearing soils as recommended herein. Footings should be excavated and concrete placed the same day in order to avoid disturbance from water or weather. Disturbance of footing subgrades by exposure to water seepage or weather conditions should be avoided. Any existing fill, disturbed, frozen, or soft subgrade soils should be removed prior to placing footing concrete. It may be desirable to place a 3 to 4-inch thick “mud mat” of lean concrete immediately on the approved footing subgrade to avoid softening of the exposed subgrade.

Forms may be used if necessary, but less subgrade disturbance is anticipated if excavations are made to the required dimensions and concrete placed against the soil. If footings are formed, the forms should be removed and the excavation backfilled as soon as possible. Water should not be allowed to pond along the outside of footings for long periods of time.

4.2.2 Pre-Consolidation Program for Spread Footing Foundation Option – IDS Building Based on the loading from the 3.5 feet of new grading fill required to achieve the finished floor elevation, consolidation settlement of the Strata B1 and C1 clays are anticipated to occur beyond the completion of the proposed construction without a pre-consolidation program. Accordingly, it is recommended that the IDS building footprint be pre-consolidated to allow the majority of the anticipated settlements to occur, prior to the building construction.

We have performed two consolidation tests for the compressible Stratum C1 St. Mary’s Formation fine-grained soils. Additionally, the consolidation properties for the Lowland Deposits were estimated based on published empirical correlations. We have used the most conservative test results from the AMSI building site for the settlement analysis at the IDS building site, since it is the same geologic formation.

We have estimated a total settlement of approximately 4 to 5 inches based on the loading from the 3.5 feet of new grading fill required to achieve the finished floor elevation. Accordingly, an earth surcharge is recommended to pre-consolidate the underling clay layers, to accelerate the settlement of these materials below the IDS building. The fill placed to reach the design subgrade for the IDS building should be placed and compacted in accordance with the earthwork requirements of Section 4.5 of this report. Table 4.2.2- 1 below provides two earth surcharge height options to be placed above the proposed finished floor level for the IDS Building. The earth surcharge should be placed and compacted in one-foot thick lifts, but there are no specific testing requirements other than to verify that the surcharge materials have a moist unit

May 27, 2020 JD185314 Page 8 weight of at least 120 pcf. We recommend that the surcharge be maintained for a minimum waiting period as presented in Table 4.2.2-1 after the full height surcharge is placed. The full height of the surcharge should extend at least 10 feet beyond the edges of the proposed building footprint. Settlement calculations are presented in Appendix C of this report.

Table 4.2.2-1: Summary of Earth Surcharge Options

Recommended Earth Surcharge Height above Finished Floor Level Remarks

5 feet of earth surcharge 6 to 8 weeks waiting period after full height surcharge placement

7 feet of earth surcharge 3 to 4 weeks waiting period after full height surcharge placement

The amount and rate of settlement under the pre-consolidation program should be monitored to evaluate when the settlement is complete. We recommend that the monitoring program for the IDS building include the placement of three settlement plates. A typical settlement plate detail is presented on Figure 2 at the end of this report. The settlement plates should be placed prior to placement of any new grading fill. The settlement plates should be monitored at least twice a week during the filling and surcharge operations and reduced to once a week after the earth surcharge is in place for the IDS building. After completion of the pre-consolidation program, the earth surcharge may be removed and the foundation construction may begin for the IDS building. We don’t recommend making any external utility connections in the building footprint until completion of the pre-consolidation program.

4.3 Finished Floor Slabs on Grade

Finished floor slabs supported by new compacted fill are considered feasible at the site. Where floor subgrades consist of existing fill, we recommend undercutting the existing fill to a depth of at least 2 feet and backfilling with new compacted fill. After undercutting the existing fill and prior to placement of any new compacted fill, the undercut subgrade should be observed during proofrolling by the geotechnical engineer to confirm that the new subgrade is suitable to receive new compacted fill.

Based on Table 4-1 of the US Army Corps of Engineers Technical Manual No. 5-809-12, for the silty and clayey sand (SM & SC) materials with 17 to 20% moisture content expected to be supporting the finished floor slabs, the finished floor slab may be designed based on a modulus of subgrade reaction KS of 150 pounds per cubic inch (pci).

All debris and soft soils near the final floor slab subgrade as a result of construction operations should be stripped and removed prior to placement of underfloor stone. A 4-inch minimum thickness of washed gravel or crushed stone meeting the requirement of AASHTO No. 57 should be placed below floor slabs on grade to serve as a capillary break. An impermeable plastic membrane should be placed on top of the crushed stone layer to assist as a moisture barrier. Special attention should be given to the surface curing of the slab in order to minimize uneven drying of the slab and associated cracking.

We recommend that mesh (fiber or welded wire fabric) reinforcement be included in the design of the floor slab to minimize the development of any shrinkage cracks near the surface of the slab. If welded wire fabric is used, the mesh should be located in the top half of the slab.

4.4 Pavements

Pavement subgrades are expected to consist of firm existing fill or new compacted fill. These materials are generally considered suitable for support of the planned roadways and parking areas. However, where pavement subgrades consist of existing fill, we recommend budgeting for undercutting the existing fill to a depth of at least 2 feet and backfilling with new compacted fill. The decision to undercut the existing fill

May 27, 2020 JD185314 Page 9 should be based on a thorough proofroll of the pavement subgrades under the observation of the geotechnical engineer.

Based on the soil laboratory test results for the materials expected at pavement subgrades, a preliminary design CBR value of 5 is recommended for pavement design purposes. If fill placed at the site is generated from off-site borrow areas, the actual CBR value for the pavement subgrades may be significantly different from the preliminary value presented herein. Therefore, CBR tests should be performed on the in-place subgrade after rough grading and installation of utilities within roadways. Final pavement sections should be based on CBR tests taken on subgrade soils at the time of construction. Concrete pavements should be utilized in loading dock areas and for dumpster pads, as applicable.

4.5 Earthwork

Fill will be required for site grading in building and pavement areas. Unsuitable existing fill, soft or loose natural soils, organic material, and rubble should be stripped to approved subgrades as determined by the geotechnical engineer. Topsoil depths presented on the boring logs should not be considered as stripping depths, as topsoil depths may vary widely across the site, particularly in wooded or previously cultivated areas. Stripping depths will probably extend to greater depths than the topsoil depths indicated herein due to the presence of minor amounts of organics, roots, and other surficial materials that will require removal as a part of the stripping operations. In addition, seasonal soil moisture variations can affect stripping depths. In general, less stripping may occur during summer months when drier weather conditions can be expected. The depth of required stripping should be determined prior to construction by the excavation contractor using test pits, probes, or other means that the contractor wishes to employ, and this determination should be the responsibility of the excavation contractor. All subgrades should be proofrolled with a minimum 20 ton, loaded dump truck or suitable rubber tire construction equipment approved by the geotechnical engineer, prior to the placement of new fill.

For building areas, the new fill should extend at least 10 feet outside building lines. For parking areas, the new fill should extend at least 5 feet outside pavement edges. These recommendations are illustrated by Figure 3 at the end of this report.

Fill material should be placed in lifts not exceeding 8 inches loose thickness, with fill materials compacted by hand operated tampers or light compaction equipment placed in maximum 4-inch thick loose lifts. Fill should be compacted at +/- 2% of the optimum moisture content to at least 95 percent of the maximum dry density per ASTM D1557.

Materials used for compacted fill for support of footings, floor slabs, and pavements should consist of soils classifying SC, SM, SP, SW, GC, GM, GP, or GW per ASTM D2487, with a maximum dry density greater than 105 pcf. It is expected that portions of soils excavated at the site will be suitable for re-use as fill based on classification. In addition, drying of excavated soils by spreading and aerating may be necessary to obtain proper compaction. This may not be practical during the wet period of the year. Accordingly, earthwork operations should be planned for early spring through late fall, when drier weather conditions can be expected. Individual borrow areas, both from on-site and off-site sources, should be sampled and tested to verify classification of materials prior to their use as fill.

Fill materials should not be placed on frozen or frost-heaved soils, and/or soils that have been recently subjected to precipitation. All frozen or frost-heaved soils should be removed prior to continuation of fill operations. Borrow fill materials should not contain frozen materials at the time of placement.

Compaction equipment that is compatible with the soil type used for fill should be selected. Theoretically, any equipment type can be used as long as the required density is achieved; however, sheepsfoot roller equipment are best suited for fine-grained soils and vibratory smooth drum rollers are best suited for granular soils. Ideally, a smooth drum roller should be used for sealing the surface soils at the end of the day or prior to upcoming rain events. In addition, compaction equipment used adjacent to walls below

May 27, 2020 JD185314 Page 10 grade should be selected so as to not impose undesirable surcharge on walls. All areas receiving fill should be graded to facilitate positive drainage of any water associated with precipitation and surface run-off.

After completion of compacted fill operations in building or pavement areas, construction of building elements or asphalt should begin immediately, or the finished subgrade should be protected from exposure to inclement weather conditions. Exposure to precipitation and freeze/thaw cycles will cause the finished subgrade to soften and become excessively disturbed. If development plans require that finished subgrades remain exposed to weather conditions after completion of fill operations, additional fill should be placed above finished grades to protect the newly placed fill. Alternatively, a budget should be established for reworking of the upper 1 to 2 feet of previously placed compacted fill.

5.0 General Limitations

Recommendations contained in this report are based upon the data obtained from the relatively limited number of test borings. This report does not reflect conditions that may occur between the points investigated, or between sampling intervals in test borings. The nature and extent of variations between test borings and sampling intervals may not become evident until the course of construction. Therefore, it is essential that on-site observations of subgrade conditions be performed during the construction period to determine if re-evaluation of the recommendations in this report must be made. It is critical to the successful completion of this project that GeoConcepts be retained during construction to observe the implementation of the recommendations provided herein.

This report has been prepared to aid in the evaluation of the site and to assist your office and the design professionals in the design of this project. It is intended for use with regard to the specific project as described herein. Changes in proposed construction, grading plans, structural loads, etc. should be brought to our attention so that we may determine any effect on the recommendations presented herein.

An allowance should be established for additional costs that may be required for foundation and earthwork construction as recommended in this report. Additional costs may be incurred for various reasons including wet fill materials, soft subgrade conditions, unexpected groundwater problems, etc.

This report should be made available to bidders prior to submitting their proposals to supply them with facts relative to the subsurface conditions revealed by our investigation and the results of analyses and studies that have been performed for this project. In addition, this report should be given to the successful contractor and subcontractors for their information only.

We recommend the project specifications contain the following statement: “A geotechnical engineering report has been prepared for this project by GeoConcepts Engineering, Inc. This report is for informational purposes only and should not be considered part of the contract documents. The opinions expressed in this report are those of the geotechnical engineer and represent their interpretation of the subsoil conditions, tests and results of analyses that they performed. Should the data contained in this report not be adequate for the contractor’s purposes, the contractor may make their own investigations, tests and analyses prior to bidding.”

This report was prepared in accordance with generally accepted geotechnical engineering practices. No warranties, expressed or implied, are made as to the professional services included in this report.

May 27, 2020 JD185314 Page 11

We appreciate the opportunity to be of service for this project. Please contact the undersigned if you require clarification of any aspect of this report.

Sincerely, GEOCONCEPTS ENGINEERING, INC.

Katherine N. Fordney, PE Paul E. Burkart, PE Project Engineer Senior Principal

DJN/KF/RSZ/PEB/clm N:\Projects\2018\JD185314\PROJECT DOCUMENTS (Reports-Letters-Drafts to Clients)\GER\Revised FY' 19 LRP GER.docx

(703) 726-8032 fax

(703) 726-803019955 Highland Vista Dr., Suite 170

Appendix A Subsurface Investigation Subsurface Investigation Procedures (1 page) Identification of Soil (1 page) Figures 4 and 5, Boring Location Plans (2 pages) Test Boring Notes (1 page) Test Boring Logs (18 pages) Figures 6 and 7, Subsurface Diagrams A-A’ and B-B’ (2 pages)

Subsurface Investigation Procedures

1. Test Borings – Cased Borings The borings are advanced by driving casing to the sampling depth. Soil within the casing is cleaned out by chopping or rotary drilling, using wash water to remove cuttings. Casing is generally advanced only to the depth necessary to prevent caving of the boring sidewalls.

2. Standard Penetration Tests Standard penetration tests are performed by driving a 2 inch O.D., 1-⅜ inch I.D. sampling spoon with a 140-pound hammer falling 30 inches, according to ASTM D1586. After an initial 6 inches penetration to assure the sampling spoon is in undisturbed material, the number of blows required to drive the sampler an additional 12 inches is generally taken as the N value. In the event 30 or more blows are required to drive the sampling spoon the initial 6 inch interval, the sampling spoon is driven to a total penetration resistance of 100 blows or 18 inches, whichever occurs first.

3. Undisturbed Tube Samples Undisturbed tube sampling is accomplished by inserting 3 inch I.D. thin walled steel tubes into the soil through the hollow stem of the augers with hydraulically actuated rams.

4. Temporary Groundwater Observation Standpipes Temporary groundwater observation standpipes were installed in test borings AMSI-2 and IDS-3 to observe groundwater levels. The standpipes were installed by inserting a 1-1/4 inch diameter plastic pipe through the 4-1/4 inch center opening of the auger. Groundwater level observations were made as shown on the test boring logs. The standpipes were removed from the test borings after completion of the final water level readings.

5. Test Boring Stakeout The test boring stakeout was provided by GeoConcepts personnel using available site plans. Ground surface elevations were estimated from topographic information contained on the site plan provided to us and should be considered approximate. If the risk related to using approximate boring locations and elevations is unacceptable, we recommend an as-drilled survey of boring locations and elevations be completed by a licensed surveyor.

May 27, 2020 JD185314 Page 14

Identification of Soil I. DEFINITION OF SOIL GROUP NAMES ASTM D2487 Symbol Group Name

Coarse-Grained Soils More than 50% retained on No. 200 sieve

Gravels More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels Less than 5% fines

GW WELL GRADED GRAVEL

GP POORLY GRADED GRAVEL

Gravels with Fines More than 12% fines

GM SILTY GRAVEL

GC CLAYEY GRAVEL

Sands 50% or more of coarse fraction passes No. 4 sieve

Clean Sands Less than 5% fines

SW WELL GRADED SAND

SP POORLY GRADED SAND

Sands with fines More than 12% fines

SM SILTY SAND

SC CLAYEY SAND

Fine-Grained Soils 50% or more passes the No. 200 sieve

Silts and Clays Liquid Limit less than

Inorganic CL LEAN CLAY

ML SILT

Organic OL ORGANIC CLAY

ORGANIC SILT

Silts and Clays Liquid Limit 50 or more

Inorganic CH FAT CLAY

MH ELASTIC SILT

Organic OH ORGANIC CLAY

ORGANIC SILT

Highly Organic Soils Primarily organic matter, dark in color, and organic odor PT PEAT

II. DEFINITION OF MINOR COMPONENT PROPORTIONS

Minor Component Approximate Percentage of Fraction by Weight Gravelly, Sandy (adjective) 30% or more coarse grained Sand, Gravel 15% to 29% coarse grained Silt, Clay 5% to 12% fine grained

III. GLOSSARY OF MISCELLANEOUS TERMS

SYMBOLS Unified Soil Classification Symbols are shown above as group symbols. Use “A” Line Chart for laboratory identification. Dual symbols are used for borderline classification.

BOULDERS & COBBLES Boulders are considered pieces of rock larger than 12 inches, while cobbles range from 3 to 12 inches.

WEATHERED ROCK Residual rock material with a standard penetration test (SPT) resistance of at least 50 blows per 6 inches.

ROCK/SPOON REFUSAL Rock material with a standard penetration test (SPT) resistance of 50 blows for 1 inch.

ROCK FRAGMENTS Angular pieces of rock which have separated from original vein or strata and are present in a soil matrix. Only used in residual soils QUARTZ A hard silicate mineral often found in residual soils. Only used when describing residual soils.

CEMENTED SAND Usually localized rock-like deposits within a soil stratum composed of sand grains cemented by calcium carbonate, iron oxide, or other minerals. Commonly encountered in Coastal Plain sediments, primarily in the Potomac Group sands (Kps).

MICACEOUS A term used to describe soil that “glitters” or is shiny. Most commonly encountered in fine-grained soils.

ORGANIC MATERIALS

(Excluding Peat)

Topsoil - Surface soils that support plant life and contain organic matter.

Lignite - Hard, brittle decomposed organic matter with low fixed carbon content (a low grade of coal).

FILL Man-made deposit containing soil, rock, and other foreign matter.

CONTAINS This is used when a soil contains a secondary component that does not apply to a USCS classification.

WITH This is used when a residual soil contains a secondary component that is included in the USCS classification.

PROBABLE FILL Soils which contain no visually detected foreign matter but which are suspect with regard to origin.

LAYERS ½ to 12 inch seam of minor soil component.

COLOR Two most predominant colors present should be described.

MOISTURE CONDITIONS Wet, moist, or dry to indicate visual appearance of specimen.

GRAIN SIZE Fine-medium-coarse

AMSI-1

AMSI-2

A A

(703) 726-8032 fax

(703) 726-803019955 Highland Vista Dr., Suite 170

Ashburn, Virginia 20147

AMSI-1

A A'

IDS-1

IDS-3

IDS-2

IDS-5

IDS-4

IDS-6B

B'

(703) 726-8032 fax

(703) 726-803019955 Highland Vista Dr., Suite 170

Ashburn, Virginia 20147

IDS-1

B B'

May 27, 2020 JD185314 Page 15

Test Boring Notes

1. Classification of soil is by visual inspection and is in accordance with the Unified Soil Classification

System.

2. Estimated groundwater levels are indicated on the logs. These are only estimates from available data and may vary with precipitation, porosity of soil, site topography, etc.

3. Sampling data presents standard penetrations for 6-inch intervals or as indicated with graphic representations adjacent to the sampling data. Where undisturbed tube samples are taken, they are designated “Shelby Tube” on the test boring log.

4. The energy applied to the split-spoon sampler using the automatic hammer is about 33 percent greater than the applied energy using the standard safety hammer. The hammer blows shown on the boring logs are uncorrected for the higher energy. N60 values are also shown on the boring logs.

5. The logs and related information depict subsurface conditions at the specific locations and at the particular time when drilled. Soil conditions at other locations may differ from conditions occurring at the test locations. Also, the passage of time may result in a change in the subsurface conditions at the test locations.

6. The stratification lines represent the approximate boundary between soil types as determined in the sampling operation. Some variation may be expected vertically between samples taken. The soil profile, groundwater level observations and penetration resistances presented on the logs have been made with reasonable care and accuracy and must be considered only an approximate representation of subsurface conditions to be encountered at the particular location.

5+12+11+11

8+7+8+9

6+8+11+18

10+13+20+23

20+22+27+17

4+3+6+5

4+6+19+17

7+9+9+13

1+2+2

10+12+6

0+0+1

0+2+2

1+2+2

18.0 17.8 16.0

14.0

12.0

10.0

8.0

6.0

4.0

-0.5

-5.5

-10.5

-15.5

A

B2

C1

Topsoil = 3 in.

Fill, orange-brown, medium, SILTY SAND, dense, moist, SM Medium dense

Fill, gray orange, medium to coarse, CLAYEY SAND WITH GRAVEL, medium dense, moist, SC Lowland deposits, gray, medium, SILTY SAND WITH GRAVEL, dense, moist, SM Very dense

Light gray, medium to coarse, medium dense

Very dense

Medium dense

Dark gray black, medium to coarse, loose

Dark gray, fine, medium dense, without gravel

St marys formation, gray, ELASTIC SILT, very soft, moist, MH

Firm

DRILLER:

DRILLING METHOD:PROJECT NUMBER:

6/24/19 - 6/26/19Wiley|Wilson

JD185314

G. Davis

18.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft.): DRILL RIG:

Mud Rotary; Automatic Hammer

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

AMSI-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.27404° N, -76.41098° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

12.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

0+0+0

0+0+3

3+12+22

4+11+13

5+6+12

5+7+10

42+44+50/4

7+6+11

3+3+6

-25.5

-30.5

-34.0

-45.5

-50.5

-55.5

-60.5

C1

C2

D1

D2

St marys formation, gray, ELASTIC SILT, very soft, moist, MH (continued)

Very soft, with sand

Soft

St marys formation, gray, medium to coarse, SILTY SAND WITH GRAVEL, dense, moist, SM

Medium dense

Choptank formation, gray, SANDY SILT, contains shells, very stiff, moist, ML

Choptank formation, gray, fine to coarse, SILTY SAND WITH GRAVEL, very dense, moist, SM

Medium dense

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 2 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

AMSI-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.27404° N, -76.41098° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

12.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

3+5+8

6+12+24

9+10+15

-75.5

-82.0

D2

D1

Choptank formation, gray, fine to coarse, SILTY SAND WITH GRAVEL, very dense, moist, SM (continued)

Choptank formation, gray, SANDY SILT, hard, moist, ML

Bottom of Borehole at 100.0 ft.

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 3 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

AMSI-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.27404° N, -76.41098° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

12.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

5+6+12+12

9+11+12+11

4+8+10+14

10+12+16+20

19+20+25+29

3+9+16+9

10+5+8+13

4+6+8+8

4+6+8

0+0+4

8+9+12

0+0+0

0+0+0

19.0 18.8 17.0

15.0

13.0

11.0

9.0

7.0

0.5

-4.5

-9.5

-14.5

A

B2

C1

Topsoil = 2 in.

Fill, orange-brown, medium, CLAYEY SAND WITH GRAVEL, medium dense, moist, SC Dense Gray-brown, medium to coarse, medium dense

Lowland deposits, gray-brown, medium, CLAYEY SAND, dense, wet, SC Gray-brown and white, very dense, with gravel

Dense

Medium dense

Lowland deposits, gray, medium, POORLY GRADED SAND, medium dense, moist, SP

Loose

Medium dense

St marys formation, gray, ELASTIC SILT, very soft, moist, MH

12.4

30.7

DRILLER:

DRILLING METHOD:PROJECT NUMBER:

6/26/19 - 6/27/19Wiley|Wilson

JD185314

G. Davis

19.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft.): DRILL RIG:

Mud Rotary; Automatic Hammer

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 2

MATERIAL DESCRIPTION

ft.

ft.

6.0

6.0

ENCOUNTERED:

703-726-8030 703-726-8032 fax

7/16/2019 2:00:35 AM

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

AMSI-2LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.27389° N, -76.41117° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

13.0

13.0

ELEV.

ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

M C

0+2+2

2+2+3

8+9+10

6+14+12

4+9+11

50/6

-23.0

-34.5

-39.5

-44.5

-49.5

-51.0

C1

C2

C1

C2

St marys formation, gray, ELASTIC SILT, very soft, moist, MH (continued) Firm, with sand

St marys formation, gray, medium to coarse, SILTY SAND, medium dense, moist, SM

Gray white, dense, with gravel

St marys formation, gray, SANDY SILT, very stiff, moist, ML

St marys formation, gray white, medium to coarse, SILTY SAND, very dense, moist, SM Bottom of Borehole at 70.0 ft.

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 2 OF 2

MATERIAL DESCRIPTION

ft.

ft.

6.0

6.0

ENCOUNTERED:

703-726-8030 703-726-8032 fax

7/16/2019 2:00:35 AM

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

AMSI-2LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.27389° N, -76.41117° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

13.0

13.0

ELEV.

ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

M C

6+10+10+9

7+9+11+15

6+8+7+5

3+2+3+3

4+2+5+6

0+0+0+1

1+2+3+4

2+2+4+5

3+3+5

3+3+3

3+4+6

3+3+4

2+2+4

8.0 7.8 6.0

2.0

0.0

-2.0

-4.0

-10.5

-15.5

-19.0

-30.5

A

B1

B2

C1

D1

Topsoil = 3 in.

Fill, light gray-brown, SANDY SILT, very stiff, moist, ML Fill, light gray-brown, medium, SILTY SAND, medium dense, moist, SM

Lowland deposits, light gray-brown, SANDY FAT CLAY, firm, moist, CH Stiff

Very soft

Lowland deposits, gray-brown, medium, CLAYEY SAND, loose, moist, SC

Medium dense

St marys, gray, LEAN CLAY, firm, moist, CL

Stiff

28.0

DRILLER:

DRILLING METHOD:PROJECT NUMBER:

7/2/19 - 7/3/19Wiley|Wilson

JD185314

G. Davis

8.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft.): DRILL RIG:

Mud Rotary; Automatic Hammer

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

IDS-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.13471° N, -76.43594° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

2.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

M C

4+5+7

3+4+7

7+9+15

4+4+4

11+29+50/5

5+5+6

4+4+8

4+6+8

5+6+9

-34.0

-44.0

-50.5

-55.5

-60.5

D1

D2

Choptank formation, gray, LEAN CLAY WITH SAND, contains shells, firm, moist, CL (continued) Very stiff

Hard

Stiff

Choptank formation, gray, medium, CLAYEY SAND, contains shells, very dense, moist, SC

Medium dense

27.7

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 2 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

IDS-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.13471° N, -76.43594° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

2.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

M C

6+10+17

4+6+14

8+19+27

-80.5

-85.5

-90.5

-92.0

D2

D1

D2

Choptank formation, gray, medium, CLAYEY SAND, contains shells, very dense, moist, SC (continued)

Choptank formation, gray, SANDY LEAN CLAY, contains shells, hard, moist, CL

Very stiff

Choptank formation, gray, fine to medium, CLAYEY SAND, contains shells, very dense, moist, SC Bottom of Borehole at 100.0 ft.

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 3 OF 3

MATERIAL DESCRIPTION

ft.6.0ENCOUNTERED:

703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES REPRESENT APPROXIMATE BOUNDARIES. THE TRANSITION MAY BE GRADUAL.

SAMPLE TYPES:

SPT

Undisturbed Sample

REMARKS:

Connelly & Associates

D. Nixon

IDS-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

Coordinates: 38.13471° N, -76.43594° W

19955 Highland Vista Dr., #170 Ashburn, Virginia 20147

B O

R E

H O

LE

/T

E S

T P

IT

J

D

G C

L O

G S

.G P

J G

E O

C O

N C

E P

T S

6.

G

D T

/2

8/

P

ID

(p pm

SPT

BLOW

COUNTS R

E

C (in

ELEV.

(ft.)

2.0ELEV.

20 40 60 80

STANDARD

PENETRATION

TEST RESISTANCE

(BPF)

DEPTH

(ft.)

S T

R A

T U

M

S A

M P

LE

T

Y P

E

G R

A P

H

IC

M C

2+2+4+5

3+3+3+6

5+4+5+8

2+3+8+5

2+3+8+5

4+3+6+5

0+0+0+1

2+5+7+8

2+1+3

1+2+4

2+2+3

2+3+4

3+3+5

8.0 7.8 6.0

4.0

2.0

0.0

-4.0

-6.0

-10.5

-15.5

-20.5

-25.5

-30.5

A

B2

B1

B2

C1

D2

Topsoil = 3 in.

Fill, gray-brown, SANDY SILT, firm, moist, ML Fill, light brown, medium, POORLY GRADED SAND, loose, moist, SP Lowland deposits, gray-brown, fine, SILTY SAND, medium dense, moist, SM Lowland deposits, gray-brown, fine, CLAYEY SAND, medium dense, moist, SC Lowland deposits, light brown, SILT WITH SAND, stiff, moist, ML

St marys formation, light brown, coarse, CLAYEY SAND, very loose, wet, SC Gray, fine to medium, medium dense, moist

Loose

St marys formation, gray, FAT CLAY, firm, moist, CH

Stiff

12.2

DRILLER:

DRILLING METHOD:PROJECT NUMBER:

7/16/19 - 7/16/19Wiley|Wilson

JD185314

G. Davis

8.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft.): DRILL RIG:

CME 550Mud Rotary; Automatic Hammer

SOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 2

MATERIAL DESCRIPTION

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703-726-8030 703-726-8032 fax

FY '19 Lab Replacement Program

NAS and Webster Outlying Field

THE STRATIFICATION LINES…