Geotech_Memo.pdf

Form FHWA-201 (Rev. 11-67)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

Use this form in lieu of transmittal slips within Dept. of Trans. When message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA- 121 for informal correspondence. PRWI 11(3) - MEMORANDUM cc: TS Reading, Hydraulics, HD, All w/ attachment

M:\PROJECTS\prwi\11(3)\Techserv\Geotech\Reports\Preliminary Memo\PRWI 11(3) Geotech Memo 2015-02-19.docx

SUBJECT: Project PRWI 11(3) – Soil Profile

TO MESSAGE/COMMENT FROM/DATE

J. Wilson, Project Manager

Through:

A. Teikari Supervisor Highway Engineer

This memorandum summarizes the results of our subsurface exploration and laboratory testing within Prince William Forest Park (PRWI) in Prince William County, Virginia.

GENERAL PROJECT INFORMATION

Project Description

The purpose of this project is to resurface and rehabilitate the South Branch Quantico Creek Bridge and perform streambank stabilization near abutments.

No undermining scour is evident at either bridge abutment, but a subsurface exploration plan was performed to verify depths to bearing strata. A Project Location Map is included as Figure 1 of Appendix A.

GEOLOGIC SETTING

Regional Geology

The Geologic Map of the National Parks in the National Capital Region1 shows the project site to be located within metavolcanic and metasedimentary rocks of the Chopawamsic Formation, Upper Ordovician. These rocks are derived from an island arc, and range in composition from rhyolite to andesite to basalt. A Site Geologic Map is included as Figure 2 of Appendix A.

Soil Survey

According to the United States Department of Agriculture Web Soil Survey2 for Prince William County, Virginia (2013), the project site is located within the Hatboro-Codorus complex (27A) soil unit. This soil unit is derived from alluvium, and consists of silt loam, silty clay loam, and sandy loam. A Soil Survey Map is included as Figure 3 of Appendix A.

PROCEDURES AND RESULTS

General

EFLHD’s Subsurface Exploration Team drilled two (2) soil borings (B-1 and B-2) at the site. Borings were drilled using a CME 750 All-Terrain Vehicle (ATV)-mounted rotary drill rig. Boring B-1 was drilled in the vicinity of the northern abutment and extended to a depth of 20.9 ft below existing site grades, while Boring B-2 was drilled in the vicinity of the southern abutment and

C. Lynch Geotechnical

M.

Abouzakhm Division Geotechnical

S. Whittemore Technical Services

02/19/2015 extended to a depth of 15.5 ft below existing site grades.

Borings were laid out in the field by EFLHD field personnel by referencing ground surface topography, measuring distances from existing surface features, and estimating right angles. Due to the methods used to locate the borings in the field, boring locations shown in Appendix B should be considered approximate Ground surface elevations at the boring locations were determined from topography plans provided by the EFLHD Survey Division. A Boring Location Map is included in Appendix B and the Boring Logs are included in Appendix C. A Subsurface Profile is also included in Appendix C.

Sampling and Field Testing

The borings were advanced using 3-¾ -inch (inside diameter) hollow-stem augers. Standard Penetration Tests (SPT) were performed using a 2-¼ -inch (outside diameter) split-spoon sampler in accordance with appropriate AASHTO guidelines. SPT soil samples were recovered by driving the split-spoon sampler 24 inches, or until refusal, into the undisturbed soil under the action of a 140-pound automatic hammer free-falling 30 inches. The number of hammer blows required to advance the split-spoon sampler through the middle 12 inches of the 24-inch sample interval is designated as the “Standard Penetration Resistance” or N-value. Split-spoon refusal is defined as 50 blows per 1-inch of penetration of the split-spoon sampler. The N-values and the number of blows required to advance the sampler through each 6-inch interval was recorded on field boring logs. N-values reported in the logs presented in Appendix C represent the field-measured values. Recovered soils were placed into glass sample jars, labeled, and transported to EFLHD Material Testing Laboratory in Sevierville, Tennessee.

Laboratory Testing

A laboratory testing program was conducted on representative soil samples recovered during the subsurface exploration. The primary purpose of the testing program was to aid in classification and evaluation of the engineering properties of soils present at the site. Laboratory testing included gradation analysis by sieve (AASHTO T 11/T 27) and classification (AASHTO M 145/ASTM D2487). All tests were conducted in general accordance with applicable ASTM/AASHTO standard test methods. The results of the laboratory testing program are presented in Appendix D and are summarized in Table 1 below:

Table 1 - Summary of Laboratory Testing Results

* = combined sample

Subsurface Conditions

In general, soils encountered in the borings can be divided into three strata:

PAVEMENT AND BASE COURSE – The borings encountered a 1± ft thick layer of pavement and base course.

FILL – Underneath the base course, fill materials were encountered and extended to depths of 14 feet to 15.5 feet below existing site grade in borings B-1 and B-2, respectively, and consists of clayey silt and sandy silt. SPT N-values ranged from 4 to 16 blows per foot (bpf).

SILTY SAND – Underneath the fill materials, residual soils were encountered in boring B-1 and extended to a depth of 20.9 feet below exiting site grades. This stratum consists of silty sand and SPT N-values ranged from 1 to 4 bpf.

BEDROCK – Bedrock was encountered underneath the silty sand stratum in boring B-1 and the fill stratum in boring B-2 and extended to the termination depths of the soil borings.

B or in g

S am p le

D ep th ft

S am p le

N o.

G ra ve l

S an d

P as si n g

#2

S ie ve

F in es

D in

A

S H

T O

C la ss

D es cr ip ti on

B-1 15-17 J-7 14.2 54.5 31.4 0.0071 A-2-4 Silty Sand

B-2 10-15 J-5 & J-6* 13.9 40.4 45.7 0.0041 A-4 Sandy Silt

References:

1 Southworth, S. and Denenny, D. (2006). Geologic Map of the National

Parks in the National Capital Region, Washington, D.C., Virginia, Maryland, and West Virginia: U.S. Geological Survey Open-File Report 2005-1331, U.S. Geological Survey, Reston, VA.

http://pubs.usgs.gov/of/2005/1331/

2 Soil Survey Staff, Natural Resources Conservation Service, United States

Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov/. Accessed November 7, 2014.

Appendices:

Appendix A – Figures Appendix B – Boring Location Map Appendix C – Boring Logs and Subsurface Profile Appendix D – Laboratory Testing Results Appendix E – Representative Photographs

APPENDIX A

Figures

REG

NP-PRWI 11(3)

TOTAL

SHEETS

SHEET

NO.

PROJECT

STATE

NC 1VA

FIGURE 1

PROJECT LOCATION MAP

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL LANDS HIGHWAY DIVISION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

Source: Southworth, S. and Denenny, D. (2006). Geologic Map of the National Parks in the National Capital Region, Washington, D.C., Virginia, Maryland, and West Virginia. USGS, Reston, VA.

1 1

SHEET

NO.

TOTAL

SHEETS

NC VA NP-PRWI 11(3)STERLING, VIRGINIA

FIGURE 2

GEOLOGIC MAP

REG STATE PROJECTU.S. DEPARTMENT OF TRANSPORTATION

FEDERAL LANDS HIGHWAY DIVISION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

NC

SHEET

NO.

PROJECT

STATEREG

PRWI 11(3)

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL LANDS HIGHWAY DIVISION

2VA

FIGURE 3

SOIL SURVEY MAP EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

TOTAL

SHEETS

PRWI 11(3)

TOTAL

SHEETS

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL LANDS HIGHWAY DIVISION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

NC VA PRWI 11(3) 2 2STERLING, VIRGINIA

FIGURE 3

SOIL SURVEY MAP

REG STATE PROJECT

SHEET

NO.

APPENDIX B

Boring Location Maps

M

P R

O J E

C T

S p r w i\ (3

T e c h s e r v G e o te c h C

A D

D P

R W I (3 F in a l

B o r in g

L o c a ti o n a p .d g n

:0

:5

-N o v -2

:0

U.S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

STERLING, VIRGINIA

REG STATE PROJECT SHEET NO.

VA

1 OF 1NC

PRINCE WILLIAM FOREST PARK

100'50'0

Approximate Scale in Feet

Boring

LEGEND

BORING LOCATION MAP

SOUTH FORK QUANTICO CREEK

TIMBER BRIDGE, SCENIC DRIVE OVER

Coordinate System: US State Plane 1983

Zone: Virginia North 4501

Project Datum: NAD 1983 (Conus)

Vertical Datum: NAVD 1988

Geoid Model: GEOID12A(Conus)

Coordinate Units: US survey feet

Distance Units: US survey feet

Height Units: US survey feet

B-1

B-2

97.3811807601.036891654.45 B-2

96.9911807579.676891733.72 B-1

TBAR98.1411807644.036891464.984005

TBAR97.4511807632.686891604.074004

TBAR96.6511807595.866891748.494003

TBAR96.9011807557.476891844.444002

TBAR107.6111807357.176891985.304001

TBAR130.7411807171.046892283.224000

NAIL90.7911807162.336891910.61203

NAIL90.3611807289.576891891.40202

NAIL89.1711807481.046891751.57201

NAIL83.9111807616.526891703.16110

NAIL91.4011807978.456891546.48102

NAIL87.7711807802.606891684.96101

NAIL88.7611807701.536891719.55100

RemarksElev.EastingNorthingPoint

Control Points Coordinate Listing

NAIL

NAIL

NAI

L

TBAR

TBAR

TBAR

4005TBAR

LIMIT

WEIGHT

TONS

14" Ø si gnN o B ic yc le

M ar ke r x4 T ra il

NO

PA

RK

ING

Clo sed sig n Foo t Tr ail

2" P

VC

5" A lum.

Pipe

N

E 11807600

N

E 11807600

NNORTHNO

PAR

KING

NO

PARKING

FLOW

SCENIC

DRIV

E

QUANTICO CREEK

SOUTH FORK

APPENDIX C

Boring Logs and Subsurface Profile

J-1

J-2

J-3

J-4

J-5

J-6

J-7

J-8

J-9

1.0

6.0

14.0

20.9

2.0

1.5

1.3

1.0

0.9

1.4

1.1

0.2

0.4

0.4-ft asphalt pavement and aggregate base course.

Medium stiff to stiff, mottled orange to brown, CLAYEY SILT. (Moist)

-FILL-

Very loose to loose, light brown SANDY SILT, with some mica and medium, rounded gravel. (Moist to wet)

-FILL-

Very loose to loose, dark brown and grey, SILTY SAND [A-2-4]. (Wet)

Fractured pieces of dark grey basalt at base of stratum.

Bottom of borehole and auger refusal at 20.9 feet.

5-5-6-8

5-9-6-6

2-2-3-2

2-2-6-4

2-2-2-4

2-1-0-1

1-2-3-4

4-2-2-3

1-50/4"

Standard Penetration Test Data

Boring Began:

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Inspector:

MATERIAL DESCRIPTION

Boring No.:

Groundwater Depth:

At Completion:

Completed:

Hole Diameter:

Boring Method:

Rock Core Diam:

Vane Shear

30 in.

140 lbs/AutomaticHammer Wt. & Type:

P. Cloudy, Warm

Encountered at:

After

Northing: 6891734 Easting: 11807580

Caved at:

Hammer Drop:

Project Name:

N o.

Prince William Forest Park, Prince William County, VA Project Datum:

(Blows / ft)

97.0 ft

Undisturbed (UD)

10/22/14

R ec ft)

Water Content %

Project Location: Boring Location:

La ye r

D ep th ft)

T yp e

Weather:

SAMPLE

S P

T B lo w s pe r in . Plastic Limit

Boring was backfilled with auger cuttings and topped with cold patch asphalt upon completion.

Liquid Limit

SPT

U. S. DEPARTMENT OF TRANSPORTATION

Penetrometer (PP in tsf) Rock Core (RQD in %)

Surface Elevation:

Sample Types:

BORING LOG

N/A

10/22/14 D. Hutchins R. KingsleyOperator:

North Abutment - Scenic Drive hrs

Remarks:

Auger Cuttings

G ra ph ic

L og

PRWI 11(3) - Timber Bridge over South Fork Quantico Creek

Density, Color, Plasticity, Size, Proportions, Moisture

D ep th S ca le ft)

E le va tio n (f ee t)

HSA

B-1

P P

US State Plane NAD 1983, Virginia North 4501

3.75 in.

B O

R

IN

G L

O G

/2

9/

:0

M

:\P R

O

JE

C T

S \P

R W

I\

(3

T E

C H

S E

R V

\G E

O T

E C

H \S

U B

S U

R F

A C

E I

N V

E S

T

IG

A T

IO

N

\B O

R

IN

G L

O G

S \P

R W

I

(3

G P

J

96.0

91.0

83.0

76.1

Sheet: 1 of 1

4"

J-1

J-2

J-3

J-4

J-5

J-6

J-7

1.0

8.0

15.5

1.7

0.9

0.9

1.4

0.4

0.6

0.0

0.35-ft asphalt pavement and aggregate base course.

Medium stiff to stiff, mottled orange, red and brown, CLAYEY SILT with lenses of brown silty sand and coarse gravel. (Moist)

-FILL-

Loose, light brown SANDY SILT, with some wood fibers [A-4]. (Moist)

-FILL-

Fractured pieces of dark grey basalt and white quartz at base of stratum.

Bottom of borehole and auger refusal at 15.5 feet.

10-8-8-9

5-5-4-6

3-8-7-6

4-3-2-2

2-5-5-5

8-50/2"

Standard Penetration Test Data

Boring Began:

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

Inspector:

MATERIAL DESCRIPTION

Boring No.:

Groundwater Depth:

At Completion:

Completed:

Hole Diameter:

Boring Method:

Rock Core Diam:

Vane Shear

30 in.

140 lbs/AutomaticHammer Wt. & Type:

P. Cloudy, Warm

Encountered at:

After

Northing: 6891654 Easting: 11807601

Caved at:

Hammer Drop:

Project Name:

N o.

Prince William Forest Park, Prince William County, VA Project Datum:

(Blows / ft)

97.4 ft

Undisturbed (UD)

10/22/14

R ec ft)

Water Content %

Project Location: Boring Location:

La ye r

D ep th ft)

T yp e

Weather:

SAMPLE

S P

T B lo w s pe r in . Plastic Limit

Boring was backfilled with auger cuttings and topped with cold patch asphalt upon completion.

Liquid Limit

SPT

U. S. DEPARTMENT OF TRANSPORTATION

Penetrometer (PP in tsf) Rock Core (RQD in %)

Surface Elevation:

Sample Types:

BORING LOG

N/A

10/22/14 D. Hutchins R. KingsleyOperator:

South Abutment - Scenic Drive hrs

Remarks:

Auger Cuttings

G ra ph ic

L og

PRWI 11(3) - Timber Bridge over South Fork Quantico Creek

Density, Color, Plasticity, Size, Proportions, Moisture

D ep th S ca le ft)

E le va tio n (f ee t)

HSA

B-2

P P

US State Plane NAD 1983, Virginia North 4501

3.75 in.

B O

R

IN

G L

O G

/2

9/

:0

M

:\P R

O

JE

C T

S \P

R W

I\

(3

T E

C H

S E

R V

\G E

O T

E C

H \S

U B

S U

R F

A C

E I

N V

E S

T

IG

A T

IO

N

\B O

R

IN

G L

O G

S \P

R W

I

(3

G P

J

96.4

89.4

81.9

Sheet: 1 of 1

2"

APPENDIX D

Laboratory Testing Results

SOIL DATA

NO.

AASHTODESCRIPTION

DEPTHSAMPLE

SOURCESYMBOL

Project No.:

Project:

Client:

Particle Size Distribution Report

P E

R C

E N

T F

IN

E

R

100 10 1 0.1 0.01 0.001200 GRAIN SIZE - mm

% + 3"

% GRAVEL

CRS. FINE

% SAND

CRS. MEDIUM FINE

% FINES

SILT CLAY

in in in

1- 1/ in in

3/ in

1/ in

3/ in

#4 #1

#2

#3

#4

#6

#1

#1

#2

0.0 0.0 14.2 5.8 14.1 34.5 31.4

(ft.)

PRWI 11(3)

Prince Wiliam Forest Pk.

FHWA/EFLHD

Scenic Dr. B-1/J-7 15-17

Particle Size Distribution Report

FEDERAL HIGHWAY ADMINISTRATION

EASTERN FEDERAL LANDS HIGHWAY DIVISION

0.0 0.0 13.9 5.4 16.2 18.8 45.7

Scenic Dr. B-2/J-5,6 10-15

Silty Sand

Sandy Silt

A-2-4

A-4

APPENDIX E

Representative Photographs

E-1

Photo 1. Apparent rock outcrop, highly fractured, at south abutment ground line, looking east.

Photo 2. Stream bank erosion upsteam of south abutment, looking south, showing alluvial deposits above bedrock outcrop at water line. Voids are likely washed-out sandy lenses.

E-2

Photo 3. CME 750 drilling for boring B-2, looking north.

Photo 4. Sample recovery for B-1, sample J-6, from depths of 13.0 to 15.0 feet (bottom of sample at right).

Photo 5. Sample recovery for B-2, sample J-2, from depths of 3.0 to 5.0 feet (bottom of sample at right).

Photo 6. Sample recovery for B-2, sample J-6, from depths of 13.0 to 13.8 feet (bottom of sample at right).