addendum no. 1 to geotechnical engineering report · laboratory testing, and engineering analysis...

Addendum No. 1 to Geotechnical Engineering Report

Goose Creek Reservoir PipelineHearford LaneAshburn, Virginia

July 25, 2019

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

July 24, 2019

Mr. Christopher Ramo Hazen and Sawyer

4035 Ridge Top Road, Suite 400 Fairfax, Virginia 22030

Subject: Addendum No. 1 to Geotechnical Engineering Report Goose Creek Reservoir Pipeline (Our JD185123)

Hearford Lane, Ashburn, Loudoun County, Virginia

Dear Mr. Ramo:

GeoConcepts Engineering, Inc. (GeoConcepts) is pleased to present the following Addendum No. 1 to our

Geotechnical Engineering Report dated September 12, 2018 prepared for Goose Creek Reservoir Pipeline near Hearford Lane in Ashburn, Loudoun County, Virginia.

This addendum includes observations, testing, and recommendations to address an access road proposed near the pipeline. The recommendations herein supplement our previously issued geotechnical report. We

have incorporated the same section numbering as our original report.

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

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.

Eric Miquelon Project Manager

[email protected]

Table of Contents 1.0 Additional Scope of Services ................................................................................................ 1 2.0 Site Description and Proposed Construction .......................................................................... 1 3.0 Subsurface Conditions ......................................................................................................... 2

3.3 Stratification ....................................................................................................................... 2 3.4 Groundwater ...................................................................................................................... 3 3.5 Soil Laboratory Test Results ................................................................................................. 3 3.8 Standard Proctor and California Bearing Ratio (CBR) Test Results .......................................... 4

4.0 Engineering Analysis ........................................................................................................... 4 4.3 Rock Excavation .................................................................................................................. 4 4.4 Earthwork ........................................................................................................................... 5 4.5 Pavements.......................................................................................................................... 6 4.6 Preliminary Slope Stability Considerations ............................................................................. 6

5.0 General Limitations ............................................................................................................. 7

Appendix A: Subsurface Investigation Appendix B: Soil Laboratory Test Results

July 24, 2019 JD185123 Page 1

1.0 Additional Scope of Services This addendum to our geotechnical engineering report presents the results of the field investigation, soil laboratory testing, and engineering analysis of the geotechnical data. This addendum specifically addresses

the following:

• Evaluate subsurface conditions within the area of the proposed access road, including the completion

of twelve hand auger borings and five drill rig borings, and soil laboratory testing.

• Recommendations regarding rock excavation for the access road construction.

• Earthwork recommendations for the access road construction, including an assessment of on-site soils

to be excavated for re-use as road subgrade material.

• An assessment of subgrade conditions for support of flexible pavements, including an estimated design

California Bearing Ratio (CBR) value based on soil laboratory test results.

• Comments to enhance stability of final slopes

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 The site is located near the north end of the Goose Creek Reservoir, northwest of Hearford Lane in Ashburn, Virginia. To our understanding, an access road has been proposed to support construction of the planned

pipeline crossing of the reservoir. This access road will extend approximately 150 feet west from the existing gravel pump station access road down a very steep grade, descending approximately 36 feet from elevation

(EL) 278 to 242, to soft wetland sediment on the eastern floodplain. This area is mapped within both the

Very Steep Slope and Floodplain Overlay Districts in the Loudoun County Online Mapping System.

During our subsurface investigation at the site in August 2018, a soil boring performed on the eastern floodplain encountered diabase rock at approximately 10 feet depth. A historical boring completed near the

existing pump station and top of the steep slope encountered rock at 4.5 feet depth. Several rock outcrops are present along the slope both above and below the existing gravel road. Both potential options for the

proposed access road are shown on the plans below.

OPTION A: Site plan provided by Hazen and Sawyer, 1/14/19

July 24, 2019 JD185123 Page 2

OPTION B: Site plan provided by Hazen and Sawyer, 3/15/19

3.0 Subsurface Conditions Subsurface conditions were investigated by completing a total of twelve hand auger borings and five drill rig borings along both potential access road alignments. Offset borings were used to confirm shallow auger

refusal depth. Elevations of the borings were determined by GeoConcepts by linear interpolation between

ground surface elevation (2-foot contour) lines shown on the subsurface exploration plan. Test boring logs and a subsurface exploration plan are presented in Appendix A of this addendum.

3.3 Stratification Fill material was encountered in our hand auger borings completed for the access road, therefore Stratum

A has been included below as an addition to the site stratification.

Stratum A

(Existing Fill)

fine to coarse, SILTY SAND, SANDY LEAN CLAY, SILT WITH GRAVEL,

SANDY ELASTIC SILT, SILTY SAND WITH GRAVEL, SILTY GRAVEL WITH SAND, FILL moist, brown, dark brown and orange brown, with

organics, construction debris and boulders

Stratum B1

(Alluvial, fine-grained)

very soft to soft, SILT (ML) and LEAN CLAY (CL) WITH SAND, moist to

wet, brown, gray, and gray-brown

Stratum B2

(Alluvial, coarse-

grained)

very loose to loose, SILTY SAND (SM), CLAYEY SAND (SC), WELL

GRADED SAND (SW), and POORLY GRADED SAND (SP), wet, brown

and gray-brown

Stratum C1 (Residual, fine-

grained)

Firm to stiff, fine to medium, SANDY LEAN CLAY (CL), SILT WITH SAND (ML), SANDY LEAN CLAY (CL), SANDY SILT (ML), GRAVELLY LEAN

CLAY WITH SAND (CL) contains rock fragments and organics, moist to wet, brown, gray-brown and orange-brown

medium dense to very dense, fine to coarse, SILTY SAND (SM), CLAYEY SAND (SC), with rock fragments and organics, moist, gray-brown

Stratum C2 (Residual, coarse-

grained)

Stratum C3

(Weathered Rock)

very dense, medium to coarse, POORLY GRADED SAND WITH SILT

(SP), WELL GRADED SAND WITH GRAVEL (SW), SILTY SAND WITH GRAVEL (SM), CLAYEY SAND WITH GRAVEL (SC), moist, gray-brown

July 24, 2019 JD185123 Page 3

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.

3.4 Groundwater Groundwater level observations were made in the field during hand auger borings. An addition to the summary of the water level readings rounded off to the nearest 0.5 feet elevation is presented below in

Table 3.4-1.

Table 3.4-1: Groundwater Readings

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

B-1 13.5 268.5

HA-5 0.5 242.0

3.5 Soil Laboratory Test Results Selected soil samples obtained from the field investigation were tested for grain size distribution, Atterberg limits, compaction characteristics using standard effort, California Bearing Ratio (CBR) and natural moisture

contents. A summary of additional soil laboratory test results is presented below in Table 3.5-1, and the results of natural moisture content tests are presented on the test boring logs in Appendix A.

Table 3.5-1: 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

B-1 2.0-4.0 Grab B2 CLAYEY SAND (SC) 0 20.5 29 17 12 13.3

B-3 0.0-2.0 Grab B1 SANDY LEAN CLAY

(CL) 1.1 64.1 42 24 18 25.8

B-3A 6.0-8.0 Grab B2 SANDY LEAN CLAY

(CL) 1 19.7 34 21 13 19.3

B-4 4.0-6.0 Grab B2 CLAYEY SAND (SC) 0 30.5 33 21 12 19.8

HA-1 0.5-1 Grab B2 SILTY GRAVEL with

sand (GM) 44.5 24.0 38 26 12 12.8

HA-2 0.5-1 Grab B2 SILTY SAND with

gravel (GM) 32.1 32.2 42 28 14 20.2

HA-3 0.0-0.25 Grab B1 sandy ELASTIC SILT

(MH) 0.8 54.5 58 33 25 58.5

HA-5 0.5-1.0 Bulk B2 SILTY SAND (SM) 0.2 46.3 59 39 20 65.5

HA-6 0.0-2.0 Grab B1 SANDY LEAN CLAY

(CL) 1.1 66.7 27 19 8 19.9

July 24, 2019 JD185123 Page 4

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

HA-7A 0.0-2.0 Grab B1 SANDY LEAN CLAY

(CL) 9.8 55.5 35 23 12 25.8

HA-10 0.0-2.0 Grab B2 SILTY GRAVEL with

sand (GM) 33.2 36.0 46 30 16 27.5

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

3.8 Standard Proctor and California Bearing Ratio (CBR) Test Results Two standard proctor tests (ASTM-698) and two CBR tests (ASTM D-1883) were performed on bulk samples

collected from test borings for the proposed access road. The results of the standard proctor and CBR tests are presented below in Table 3.8-1.

Table 3.8-1: CBR Values

Test Boring No. Minimum Resulting

CBR Value

Approximate Depth Range for Minimum Resulting CBR Value*

(feet)

B-4 3.3 0.5 – 5.0

HA-5 2.0 0.5 – 1.0

*Depth measured from top of existing subgrade.

4.0 Engineering Analysis Additional comments and recommendations regarding rock excavation, earthwork, pavements, and slope

stability are presented herein.

4.3 Rock Excavation A historical boring completed near the top of slope encountered diabase rock at about 4.5-feet below the existing gravel access road surface. Boring (PC-1) completed for the planned pipeline, located within 15-

feet of the slope bottom, encountered rock at 10-feet below wetland sediments. Intact bedrock outcrop is

apparent on slope areas both above and below the existing access road. Based on these rock depths and the presence of rock outcrop, shallow depth to rock along the steep slope is likely. The hand auger borings

completed along the slope encountered shallow refusal between 0.2-and 2.1-feet below ground surface. Manually advanced hand auger boring refusal depths should not be considered depth to rock. Based on

visual observations and results of the hand auger borings, the existing fill material contains large cobbles,

boulders, and construction debris. It is believed that this existing fill was derived from rock and soil excavation to accommodate the existing gravel pump station access road.

Rock excavation such as hoe-ramming or excavator rock ripping may be required for the proposed access

road construction. Where rock removal is necessary, removal should extend at least six-inches below the bottom of the planned pavement section and backfilled to proposed subgrade elevations with compacted

21-B subbase material. Rock removal should be planned and monitored such that the existing gravel road

July 24, 2019 JD185123 Page 5

is not undermined. Blasting may cause excessive fracturing of the rock and possibly destabilize the slope,

and therefore, is not recommended for use during access road construction. Additionally, environmental concerns related to the municipal reservoir will limit blasting in the vicinity.

Geologic mapping of the excavation should be completed by a qualified engineering geologist as the

excavation proceeds. Thorough excavation mapping will provide a permanent record of the geologic

conditions exposed in the excavation. In addition, excavation mapping will allow for the identification of any unanticipated or adverse geologic conditions, including unfavorable bedrock discontinuity orientations,

extremely fractured bedrock, groundwater seeps, and the presence of soil seams. During excavation mapping, photographs should be taken of the excavation sidewalls and construction activity. Photographs

should be labeled with the date, subject, direction of view, name of person taking the photograph, and any

other supplemental information that will provide meaning to the photograph.

4.4 Earthwork Fill may be required for construction of the access road subgrade. Prior to placement of new fill, the access road subgrade should be stripped of organic material, construction debris, loose natural soils and existing

fill, loose cobbles, and boulders, to approved subgrades as determined by the geotechnical engineer. Topsoil, crushed stone, and existing fill depths presented on the boring logs should not be considered

stripping depths, as these depths may vary across the site. During excavation of existing material, care

should be taken to not undermine the existing gravel road.

We anticipate that the grading work for the proposed access road will include cuts on the side of the road closer to the slope and fill placement to build up the outside edge of the road nearer to the reservoir. Once

the unacceptable existing material has been stripped and rock removal as necessary has been completed, new compacted fill should be placed to reach proposed road subgrade elevations. 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

D698. The upper 6 inches of pavement subgrades should be compacted to at least 100 percent of the maximum dry density per the same standard.

Based on recent preliminary grading plans, it is not anticipated that fill placement will exceed 10 feet in depth. However if new fills or backfills exceed 10 feet in depth, we recommend that the new fills below 10

feet depth be compacted to at least 98% of the maximum dry density per ASTM D698. The purpose of the higher compaction criteria is to reduce total and differential settlement of the fill. After the fills have

reached final grade, it is recommended that a waiting period of 30 to 60 days be maintained to allow any

substantial consolidation settlement of the fill and existing soil profile to occur, prior to commencing construction of any pavement or gravel road base on top of the fill.

Fill placed along slopes steeper than 5H:1V should be benched into the existing slope. Benches should

consist of minimum 8 feet wide level cut, and at least one such bench should be used for each 3 feet of vertical rise of fill placed.

Materials used for compacted fill for support of pavements should consist of soils classifying CL, ML, 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 the majority of soils excavated at the site will be suitable for re-use as fill based on classification. However, the Stratum A existing fill may not be suitable for re-use as new compacted fill due

to large boulders, cobbles, and deleterious man-made materials in the fill. 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.

July 24, 2019 JD185123 Page 6

The weathered rock of Stratum C2 may also be suitable for re-use as fill. With limited exposure and

manipulation, the weathered rock will eventually breakdown into smaller size particles. If the weathered rock is placed in a fill without sufficient fines to fill void spaces adjacent to larger size particles, degradation

of the larger disintegrated rock particles may result in collapse of the individual void spaces, and subsequent undesirable settlement. In order to prevent the improper placement of weathered rock materials due to

the non-durable nature of this material, we recommend that the weathered rock be placed as a soil fill and

not as rock fill. This will require that sufficient mechanical effort be used to breakdown and crush the disintegrated rock into particles not larger than 8 inches in mean diameter, with approximately 50 percent

materials passing the U.S. Standard No. 40 sieve. These criteria should be able to be met by compacting with a CAT 815 sheepsfoot roller or similar sized equipment, in lifts not exceeding 8 inches in thickness

prior to compaction.

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. All areas receiving fill should be graded to facilitate positive drainage of any water associated with precipitation and surface run-off. Drainage culverts should be installed as

necessary to reduce erosion of the access road during heavy rain events.

After completion of compacted fill operations in pavement areas, placement of road base gravel or

construction of the pavement section 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.

4.5 Pavements Pavement subgrades are expected to consist of natural soils or new compacted fill. These materials are generally considered suitable for support of the planned roadways. 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 should be based on a thorough proofroll of the pavement subgrades under the observation of the geotechnical engineer.

Based on the soil laboratory California Bearing Ratio (CBR) test results for the materials expected at

pavement subgrades, a preliminary design CBR value of 2 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.

4.6 Preliminary Slope Stability Considerations This site includes steep existing slopes up to about 1.3H:1V, and the presence of the elastic silt and boulders within the existing fill is likely to have an impact on the final grading. Use of subdrainage, culverts, and

cut-off trenches along finished slopes may also be necessary to intercept potential perched water flow or

to handle specific spring or seepage conditions, in combination with the slope stabilization measures. No seeps or springs were noted along the steep slope, but the presence of these features may not be apparent

July 24, 2019 JD185123 Page 7

until site grading work begins. Ground cover vegetation is assumed on finished slopes and will be necessary

for control of surface runoff and erosion. Soil erosion may also be reduced by the use of filter socks, diversion and culvert structures, and erosion control matting.

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, 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, rock excavation, 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.

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.

Eric Miquelon Paul Burkart, PE

Project Manager Senior Principal EM/PEB/clm

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Appendix A Subsurface Investigation Subsurface Investigation Procedures (1 page)

Identification of Soil (1 page)

Figure 4, Access Road Boring Location Plan (1 page)

Hand Auger Boring Notes (1 page)

Test Boring Notes (1 page)

Hand Auger and Drill Rig Boring Logs (21 pages)

Subsurface Investigation Procedures 1. Test Borings – Hollow Stem Augers

The borings are advanced by turning an auger with a center opening of 2-¼ or 3-¼ inches. A plug device

blocks off the center opening while augers are advanced. Cuttings are brought to the surface by the auger flights. Sampling is performed through the center opening in the hollow stem auger, by standard methods,

after removal of the plug. Usually, no water is introduced into the boring using this procedure.

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. Hand Auger Borings Hand auger borings were advanced using a 3.5-inch diameter auger attached to steel rods and handle

extensions. The auger is manually advanced from the ground surface with excavated soil removed from the borehole with each pass of the auger.

4. Dynamic Cone Penetration Tests Testing is performed by driving a 1-¾ inch diameter penetration cone with a 15-pound hammer free falling

20 inches. The number of blows required to drive the cone for an interval of 1-¾ inches is recorded. The cone was generally driven for three intervals at each test depth, with the first interval considered a seating

interval.

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.

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 50

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

B-5

B-3

B-4HA-6

HA-7HA-12

HA-8HA-9

HA-11

HA-10

HA-1

HA-2

HA-3HA-4

153471033

B-260E

68C

68B

64D

W152268334

HA-5

B-1

NO. DATE REVISION

Fig. 4ACCESS ROAD BORING LOCATION PLAN

GOOSE CREEK RESERVOIR ACCESS ROADHEARFORD LANE, ASHBURN, VIRGINIAB-1

HA-1

39°03'04.49"N 77°31'43.77"W

39°03'02.76"N 77°31'36.39"W

39°03'07.12"N77°31'37.69"W

39°0

2'59

.92"

N77

°31'

41.3

6"W

Hand Auger Boring Notes

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

System. Soil classification symbols are in accordance with ASTM D2488 by visual observation.

2. Estimated groundwater levels are indicated on the log. These are only estimates from available data

and may vary with precipitation, porosity of soil, site topography, etc.

3. Sampling data presents Dynamic Cone Penetration (DCP) values for 1-¾ inch intervals.

4. 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.

5. 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, water 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 locations.

6. Refusal depths on the hand auger logs are the depths at which obstructions were encountered and the hand auger could no longer be advanced.

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.

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.

7. Weathered rock is defined as residual earth material with a penetration resistance between 50 blows

per 6 inches and refusal. Spoon refusal at the surface of rock, boulders, or obstructions is defined as a penetration resistance of 50 blows for 1-inch penetration or less. Auger refusal is taken as the depth

at which further penetration of the auger is not possible without risking significant damage to the drilling equipment.

1+2+4+5

3+4+7+10

5+10+13+9

4+7+9+11

5+8+11+18

50/6

50/0

1.5

2

2

2

2

0.5

0

282.0281.8

280.0

278.0

276.0

268.5

268.0

C1

C2

C3

Topsoil = 3 in.Residual, brown, fine to medium, SANDY LEAN CLAY, firm,moist, CL

Residual, mottled gray-brown, medium to coarse, SILTYSAND, medium dense, moist, SM

Dense

Medium dense

Weathered rock, brown-gray, medium to coarse, SILTY SANDWITH GRAVEL, very dense, moist, SMAuger and Spoon Refusal at 14.0 ft.

13.3

DRILLER:

DRILLING METHOD:PROJECT NUMBER:

5/30/19 - 5/30/19Hazen and Sawyer

JD185123

D. Lazaro

282.0 ±

DATES DRILLED:OWNER/CLIENT:

GROUND SURFACE ELEVATION (ft.): DRILL RIG:

CME 5502.25 ID HSA; Automatic HammerSOIL

DRILLING CONTRACTOR:

BORING NUMBER:

SHEET 1 OF 1

MATERIAL DESCRIPTION

ft.

ft.

13.5

12.5UPON COMPLETION:

ENCOUNTERED:

703-726-8030703-726-8032 fax

Goose Creek Reservoir Pipeline Access Road

Hearford Lane Ashburn, Loudoun County, Virginia

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

SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling

P. HalbertB-1LOCATION:

LOGGED BY:

GROUND WATER LEVELS:

LOCATION:

PROJECT:

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

BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

268.5

269.5

ELEV.

ELEV. ELEV. 273.0

20 40 60 80

STANDARDPENETRATION

TEST RESISTANCE(BPF)

9.0 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

MC

(%

)

>>>>

1+2+3+5

5+4+5+7

3+4+7+8

4+5+9+8

3+28+50/6

50/0

18

20

24

24

16

0

274.0273.5

272.0

268.0

266.0

262.0

C1

C2

C3

Topsoil = 6 in.Residual, brown, fine to medium, SILT WITH SAND, firm, moist,ML

Residual, brown, fine to medium, SANDY LEAN CLAY, stiff, moist,CL

Residual, brown, fine to medium, CLAYEY SAND, medium dense,moist, SC

Weathered rock, brown-gray, medium to coarse, POORLYGRADED SAND WITH SILT, very dense, moist, SP

Auger and Spoon Refusal at 12.0 ft.

DRILLER:



JD185123

D. Lazaro

274.0 ±





BORING NUMBER:

SHEET 1 OF 1


NOT ENCOUNTERED UPON COMPLETION

NOT ENCOUNTERED DURING DRILLING

703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling


LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 267.3

20 40 60 80

STANDARDPENETRATION


6.7 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

>>

>>

1+2+3+8

5+8+50/2

50/0

24

6

0

270.0269.8

268.0

266.0

C1

Topsoil = 3 in.Residual, brown, fine to medium, SANDY SILT, contains rockfragments, firm, moist, ML

Residual, gray-brown, LEAN CLAY, contains rock fragments,very hard, moist, CL


25.8

DRILLER:



JD185123

D. Lazaro

270.0 ±





BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling


LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 267.5

20 40 60 80

STANDARDPENETRATION


2.5 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

MC

(%

)

>>

>>

4+7+14+20

18+18+20+21

13+28+24+50

50/0

20

24

22

0

270.0

266.0

264.0

262.0

258.5

C1

C2

Auger probe down to 4.0 ft.

Residual, brown, fine to medium, SILT WITH SAND, containsorganics, very stiff, moist, ML

Residual, brown-gray, fine to medium, GRAVELLY LEANCLAY WITH SAND, hard, moist, CL

Residual, brown, fine to medium, CLAYEY SAND, very dense,moist, SC


19.3

DRILLER:



JD185123

D. Lazaro

270.0 ±





BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling

P. HalbertB-3ALOCATION:

LOGGED BY:


LOCATION:

PROJECT:

Offset 5.0 ft northwest from B-3.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 263.3

20 40 60 80

STANDARDPENETRATION


6.7 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

MC

(%

)

>>

2+3+3+5

3+6+6+8

6+7+12+13

5+7+8+16

12+11+11+15

10+50/5

50/0

18

24

18

24

24

11

0

266.0265.8

264.0

252.5

249.5

C1

C2

C3

Topsoil = 3 in.Residual, brown, fine to medium, SILT WITH SAND, firm,moist, ML

Residual, brown, medium to coarse, CLAYEY SAND, containsroots, medium dense, moist, SC

Weathered rock, brown-gray, medium to coarse, WELLGRADED SAND WITH GRAVEL, very dense, moist, SW


19.8

DRILLER:



JD185123

D. Lazaro

266.0 ±





BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling


LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 257.5

20 40 60 80

STANDARDPENETRATION


8.5 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

MC

(%

)>>

>>

2+4+4+5

3+5+8+11

11+11+8+42

50/0

18

24

18

0

275.0274.3

273.0

269.0

C1

C2

Topsoil = 9 in.

Residual, orange-brown, fine to medium, SILT WITH SAND, stiff,moist, ML

Residual, brown-gray, medium to coarse, CLAYEY SAND, mediumdense, moist, SC


DRILLER:



JD185123

D. Lazaro

275.0 ±





BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling


LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 270.5

20 40 60 80

STANDARDPENETRATION


4.5 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

>>

50/6

50/4

50/0

12

4

0

275.0

269.0

267.0

265.0

C3


Weathered rock, brown-gray, medium to coarse, CLAYEY SANDWITH GRAVEL, very dense, moist, SC

Weathered rock, brown-gray, medium to coarse, WELL GRADEDSAND WITH GRAVEL, very dense, moist, SW


DRILLER:



JD185123

D. Lazaro

275.0 ±





BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

SPT

REMARKS:

Recon Drilling

P. HalbertB-5ALOCATION:

LOGGED BY:


LOCATION:

PROJECT:

Offset 5.0 ft northwest from B-5.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

SPTBLOW

COUNTS RE

C(in

)

ELEV.(ft.)

ELEV. 268.4

20 40 60 80

STANDARDPENETRATION


6.6 ft.CAVED:

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

5

10

15

>>

>>

>>

13+9+1013+9+1013+9+1013+9+1013+9+10

275.0

274.6

273.6

A

Crushed stone = 5 in.

Fill, dark brown, medium to coarse, SILTY GRAVEL WITH SAND, moist, GM

Hand Auger Refusal at 1.4 ft.

12.8

DRILLER:



JD185123

P. Halbert

275.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample

DynamicConePenetrometer

REMARKS:

GeoConcepts Engineering

P. HalbertHA-1LOCATION:

LOGGED BY:


LOCATION:

PROJECT:

Two offsets attempted; refused at 1-foot or less.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

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IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

2+3+32+3+32+3+32+3+32+3+3

272.0

271.7

269.9

A

Crushed stone = 4 in., with construction debris

Fill, dark brown, medium to coarse, SILTY SAND WITH GRAVEL, moist, SM


20.2

DRILLER:



JD185123

E. Miquelon

272.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:

Two offsets attempted; refused at 6-inches or less.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

11+22+30/

1.3

11+22+30/

1.3

11+22+30/

1.3

11+22+30/

1.3

11+22+30/

1.3

264.0263.9

263.4

A

Crushed stone = 1 in.Fill, dark brown, fine to coarse, SANDY ELASTIC SILT, with construction debris,contains boulders, moist, MH


58.5

DRILLER:



JD185123

E. Miquelon

264.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:



BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

30/

0

30/

0

30/

0

30/

0

30/

0

244.0

243.8

AFill, fine to coarse, SILTY SAND WITH GRAVEL, with construction debris, containsboulders, moist, SM


DRILLER:



JD185123

E. Miquelon

244.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

REMARKS:



LOGGED BY:


LOCATION:

PROJECT:



BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

23+19+1723+19+1723+19+1723+19+1723+19+17

240.0

239.5

238.2

B2

Topsoil = 6 in.

Alluvial, dark brown, fine to coarse, SILTY SAND, contains organics, moist, SM


65.5

DRILLER:



JD185123

E. Miquelon

240.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1


ft.0.8


ENCOUNTERED:

703-726-8030703-726-8032 fax




SAMPLE TYPES:

Bulk Sample


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:

Two offsets attempted; soil in the first location was too wet to obtain sample recovery, the second attempt refused at1.4-feet.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

239.2ELEV.

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

8+11+138+11+138+11+138+11+138+11+13

257.0

255.1

C1

Residual, orange-brown, fine to medium, SILT WITH SAND, contains roots,moist, ML


19.9

DRILLER:



JD185123

P. Halbert

257.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:

One offset attempted; refusal at 1.5 ft.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

261.0

260.5

C1

Residual, brown, fine to medium, SANDY LEAN CLAY, moist, CL


25.8

DRILLER:



JD185123

P. Halbert

261.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample

REMARKS:



LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

9+12+14

17+22+30

9+12+14

17+22+30

9+12+14

17+22+30

9+12+14

17+22+30

9+12+14

17+22+30

261.0

259.0

C1

Residual, brown, SANDY LEAN CLAY, moist, CL


25.8

DRILLER:



JD185123

P. Halbert

261.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:


P. HalbertHA-7ALOCATION:

LOGGED BY:


LOCATION:

PROJECT:

Offset 5.0 ft north from HA-7.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

19+14+27

30/ 1.6

30/ 0.8

30/ 1

258.0

257.0



DRILLER:



JD185123

P. Halbert

258.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:

Continuous DCP Test, No sample observed.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

253.0

252.8

C1

Residual, brown, SILT WITH GRAVEL, moist, ML


DRILLER:



JD185123

P. Halbert

253.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

REMARKS:



LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

15+30/ 0.3

30/ 0.8

15+30/

0.3

30/

0.8

252.0

251.3

C1

Residual, brown, SILT WITH GRAVEL, moist, ML


DRILLER:



JD185123

P. Halbert

252.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:


P. HalbertHA-9ALOCATION:

LOGGED BY:


LOCATION:

PROJECT:

Offset 3.0 ft south from HA-9.


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

10+17+30/

1.5

10+17+30/

1.5

10+17+30/

1.5

10+17+30/

1.5

10+17+30/

1.5

253.0

252.3

251.0

A

Topsoil = 8 in.

Fill, dark brown, medium to coarse, SANDY SILT WITH GRAVEL, containsorganics, moist, ML


27.5

DRILLER:



JD185123

E. Miquelon

253.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:

Grab Sample


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:


BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

MC

(%

)

1+1+1

2+3+4

6+30/

1

1+1+1

2+3+4

6+30/

1

1+1+1

2+3+4

6+30/

1

1+1+1

2+3+4

6+30/

1

1+1+1

2+3+4

6+30/

1

257.0

255.9



DRILLER:



JD185123

E. Miquelon

257.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:



BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

2+2+5

3+7+4

4+8+30/

1

2+2+5

3+7+4

4+8+30/

1

2+2+5

3+7+4

4+8+30/

1

2+2+5

3+7+4

4+8+30/

1

2+2+5

3+7+4

4+8+30/

1

259.0

257.8



DRILLER:



JD185123

E. Miquelon

259.0 ±



Hand AugerSOIL


BORING NUMBER:

SHEET 1 OF 1




703-726-8030703-726-8032 fax




SAMPLE TYPES:


REMARKS:



LOGGED BY:


LOCATION:

PROJECT:



BO

RE

HO

LE/T

ES

T P

IT G

OO

SE

CR

EE

K R

ES

ER

VO

IR P

IPE

LIN

E A

CC

ES

S R

OA

D -

TH

IS O

NE

.GP

J G

EO

CO

NC

EP

TS

201

7021

6.G

DT

7/2

5/1

9

DCPBLOW

COUNTS

Geo

prob

eP

en. (

in)

ELEV.(ft.)

DEPTH(ft.)

ST

RA

TU

M

SA

MP

LET

YP

E

GR

AP

HIC

Appendix B Soil Laboratory Test Results Liquid and Plastic Limit, and Grain Size Analysis Test Data (24 pages)

Moisture Density Relationship Test Data (12 pages)

CBR Test Data (2 pages)

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

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

LIQUID AND PLASTIC LIMIT - ASTM D4318Project No. JD185123 Project Name Goose Creek

Sample ID B-1 Depth (Feet) 2.0-4.0

Lab Order No. 4691-1 Date 05.31.2019

Material Description LL PL PI % Passing USCS w (%)#4 #200

CLAYEY SAND 29 17 12 100.0 20.5 SC 13.3

Color Dark Brown AASHTO Classification A-2-6

Test Method: ASTM D 4318Soil Classification by ASTM D2487 and AASHTO M 145

Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)



GRAIN SIZE ANALYSIS - ASTM D422Project No. JD185123 Project Name Goose Creek


Lab Order No. 4691-1 Date 05.31.2019

SIEVE % Passing USCS Group Symbol SC1 ½ " 100 USCS Group Name CLAYEY SAND3/4" 100 Cu ---3/8" 100 Cc ---#4 100 LL 29#10 94 PI 12#20 63 Gravel 0.0#40 44 Sand 79.5#60 37 Fines 20.5#100 30 AASHTO Classification A-2-6#200 20 Color Dark BrownPan -- Test Method: ASTM D 422

Soil Classification by ASTM D2487 and AASHTO M 145

Reviewed by:

0.010.11101000

102030405060708090

100

Grain Size Diameter (mm)

No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner




Sample ID B-3A Depth (Feet) 0.0-2.0

Lab Order No. 4691-2 Date 05.31.2019


sandy Lean Clay 42 24 18 98.9 64.1 CL 25.8



Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4691-2 Date 05.31.2019

SIEVE % Passing USCS Group Symbol CL1 ½ " 100 USCS Group Name sandy Lean Clay3/4" 100 Cu ---3/8" 100 Cc ---#4 99 LL 42#10 96 PI 18#20 87 Gravel 1.1#40 82 Sand 34.9#60 77 Fines 64.1#100 71 AASHTO Classification A-7-6#200 64 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4691-3 Date 05.31.2019


CLAYEY SAND 34 21 13 98.9 19.7 SC 19.3



Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4691-3 Date 05.31.2019



Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner



LIQUID AND PLASTIC LIMIT - ASTM D4318Project No. JD185123 Project Name Goose Creek Resevoir - Access Road


Lab Order No. 4694-N-16 Date 06.04.2019

Material Description LL PL PI% Passing

USCS w (%)#4 #200


Color Brown AASHTO Classification A-6


Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)



GRAIN SIZE ANALYSIS - ASTM D422Project No. JD185123 Project Name Goose Creek Resevoir - Access Road



SIEVE % Passing USCS Group Symbol CL1 ½ " 100 USCS Group Name sandy Lean Clay3/4" 100 Cu ---3/8" 100 Cc ---#4 100 LL 34#10 100 PI 14#20 97 Gravel 0.0#40 94 Sand 31.3#60 90 Fines 68.6#100 81 AASHTO Classification A-6#200 69 Color BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4691-4 Date 05.31.2019


CLAYEY SAND 33 21 12 100.0 30.5 SC 19.8



Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4691-4 Date 05.31.2019



Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner



LIQUID AND PLASTIC LIMIT - ASTM D4318Project No. JD185123 Project Name Goose Creek Resevoir

Sample ID HA-1 Depth (Feet) 0.5-1.0 ft

Lab Order No. 4559-1 Date 02.11.2019


SILTY GRAVEL with sand 38 26 12 55.5 24.0 GM 12.8



Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)



GRAIN SIZE ANALYSIS - ASTM D422Project No. JD185123 Project Name Goose Creek Resevoir


Lab Order No. 4559-1 Date 02.11.2019

SIEVE % Passing USCS Group Symbol GM1 ½ " 100 USCS Group Name SILTY GRAVEL with sand3/4" 94 Cu ---3/8" 71 Cc ---#4 55 LL 38#10 45 PI 12#20 39 Gravel 44.5#40 35 Sand 31.5#60 32 Fines 24.0#100 28 AASHTO Classification A-2-6#200 24 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4559-2 Date 02.11.2019


SILTY SAND with gravel 42 28 14 67.9 32.2 SM 20.2



Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4559-2 Date 02.11.2019

SIEVE % Passing USCS Group Symbol SM1 ½ " 100 USCS Group Name SILTY SAND with gravel3/4" 100 Cu ---3/8" 76 Cc ---#4 68 LL 42#10 60 PI 14#20 53 Gravel 32.1#40 47 Sand 35.8#60 42 Fines 32.2#100 37 AASHTO Classification A-2-7#200 32 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4559-3 Date 02.11.2019


sandy Elastic Silt 58 33 25 99.2 54.5 MH 58.5



Reviewed by

10090807060504030201000

10

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40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

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PI)





Lab Order No. 4559-3 Date 02.11.2019

SIEVE % Passing USCS Group Symbol MH1 ½ " 100 USCS Group Name sandy Elastic Silt3/4" 100 Cu ---3/8" 100 Cc ---#4 99 LL 58#10 93 PI 25#20 79 Gravel 0.8#40 69 Sand 44.7#60 62 Fines 54.5#100 58 AASHTO Classification A-7-5#200 55 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4559-4 Date 02.11.2019


SILTY SAND 59 39 20 98.8 46.3 SM 65.5



Reviewed by

10090807060504030201000

10

20

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40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

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PI)





Lab Order No. 4559-4 Date 02.11.2019

SIEVE % Passing USCS Group Symbol SM1 ½ " 100 USCS Group Name SILTY SAND3/4" 100 Cu ---3/8" 100 Cc ---#4 99 LL 59#10 90 PI 20#20 74 Gravel 1.2#40 62 Sand 52.4#60 56 Fines 46.3#100 52 AASHTO Classification A-7-5#200 46 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner




Sample ID HA-6 Depth (Feet) 2

Lab Order No. 4691-5 Date 05.31.2019



Color Dark Brown AASHTO Classification A-4


Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4691-5 Date 05.31.2019

SIEVE % Passing USCS Group Symbol CL1 ½ " 100 USCS Group Name sandy Lean Clay3/4" 100 Cu ---3/8" 100 Cc ---#4 99 LL 27#10 97 PI 8#20 95 Gravel 1.1#40 92 Sand 32.2#60 89 Fines 66.7#100 81 AASHTO Classification A-4#200 67 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4691-6 Date 05.31.2019



Color Dark Gray AASHTO Classification A-6


Reviewed by

10090807060504030201000

10

20

30

40

50

60

LIQUID LIMIT (LL)

PLAS

TICI

TY I

ND

EX (

PI)





Lab Order No. 4691-6 Date 05.31.2019

SIEVE % Passing USCS Group Symbol CL1 ½ " 100 USCS Group Name sandy Lean Clay3/4" 100 Cu ---3/8" 95 Cc ---#4 90 LL 35#10 85 PI 12#20 79 Gravel 9.8#40 74 Sand 34.7#60 69 Fines 55.5#100 64 AASHTO Classification A-6#200 56 Color Dark GrayPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner





Lab Order No. 4691-7 Date 05.31.2019


SILTY GRAVEL with sand 46 30 16 66.8 36.0 GM 27.5



Reviewed by

10090807060504030201000

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LIQUID LIMIT (LL)

PLAS

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PI)





Lab Order No. 4691-7 Date 05.31.2019

SIEVE % Passing USCS Group Symbol GM1 ½ " 100 USCS Group Name SILTY GRAVEL with sand3/4" 100 Cu ---3/8" 72 Cc ---#4 67 LL 46#10 64 PI 16#20 58 Gravel 33.2#40 51 Sand 30.7#60 44 Fines 36.0#100 40 AASHTO Classification A-7-5#200 36 Color Dark BrownPan -- Test Method: ASTM D 422


Reviewed by:

0.010.11101000

102030405060708090

100


No. 2

00

No. 4

0

No. 4¾ in

Perc

ent F

iner



MOISTURE DENSITY RELATIONSHIP - VTM-001Project No. JD185123 Project Name Goose Creek Resevoir - Access Road



TEST RESULTS Before Correc. After Correc.Maximum Dry Density (pcf) 106.4 -- ColorOptimum Moisture Content (%) 19.4 -- Brown

Material ClassificationNat.

Moist.(%)

Sp. G.(Assumed) LL PI % > # 4 % < #200

sandy Lean ClayUSCS AASHTO

20.9 2.6 34 14 0.0 68.6CL A-6

VTM-001

Reviewed by

2422201816141290

110

Water Content (%)

Dry

Den

sity

(pc

f)

100% Saturation



MOISTURE DENSITY RELATIONSHIP - VTM-001Project No. JD185123 Project Name Goose Creek Resevoir


Lab Order No. 4559-4 Date 02.11.2019

TEST RESULTS Before Correc. After Correc.Maximum Dry Density (pcf) 80.3 -- ColorOptimum Moisture Content (%) 33.0 -- Dark Brown

Material ClassificationNat.

Moist.(%)

Sp. G.(Assumed) LL PI % > # 4 % < #200

SILTY SANDUSCS AASHTO

65.5 2.6 59 20 1.2 46.3SM A-7-5

VTM-001

Reviewed by

3937353331292772

Water Content (%)

Dry

Den

sity

(pc

f)

100% Saturation



CALIFORNIA BEARING RATIO (CBR) TEST - VTM-008Project No. JD185123 Project Name Goose Creek Resevoir - Access Road



Molded Dry Density (pcf) 105.8 No Linearity Correction 0.000Moisture (%) 19.7 No Surcharge (lbs) 10

Percent ofMax. Density (%)

99.4 Max Swell (%) 0.3

Material Description sandy Lean ClaySoaked USCS CL

Dry Density (pcf) 105.4 Max Density 106.4Moisture (%) 22.2 Optimum Moisture (%) 19.4Percentage ofMax. Density (%) 99.1 LL 34

PI 14Color Brown

CBR (%)0.1 in. 3.30.2 in. 3.7

Reviewed by:

0.500.400.300.200.100.000

20

40

60

80

100

120

Penetration (in.)

Pene

trat

ion

Resi

stan

ce (

psi)



CALIFORNIA BEARING RATIO (CBR) TEST - VTM-008Project No. JD185123 Project Name Goose Creek Resevoir


Lab Order No. 4559-4 Date 02.11.2019

Molded Dry Density (pcf) 79.8 No Linearity Correction 0.012Moisture (%) 33.5 No Surcharge (lbs) 25

Percent ofMax. Density (%)

99.3 Max Swell (%) 1.9

Material Description SILTY SANDSoaked USCS SM

Dry Density (pcf) 78.3 Max Density 80.3Moisture (%) 39.7 Optimum Moisture (%) 33.0Percentage ofMax. Density (%) 97.5 LL 59

PI 20Color Dark Brown

CBR (%)0.1 in. 2.00.2 in. 2.9

Reviewed by:

0.500.400.300.200.100.000

20

40

60

80

100

120

Penetration (in.)

Pene

trat

ion

Resi

stan

ce (

psi)

addendum no. 1 to geotechnical engineering report · laboratory testing, and engineering analysis...

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