Geotech Memo.pdf

“D el iv er in g rig ht s ol ut io ns th ro ug h q ua lit y se rv ic es a nd e ng in ee rin g ex ce lle nc e”

Prepared for

WSP

July 28, 2022 (Revised)

Geotechnical Engineering Report

Fort Belvoir Kingman and Walker Gates Federal Aid Project No. VA ST FB_KNGMN/WLKR_GTS Fairfax County, Virginia

Chantilly, VA Williamsburg, VA Washington, DC

Gaithersburg, MD

4170 Lafayette Center Drive, Suite 500, VA 20151 ● www.dmyec.com ● Phone: (703) 665-0586 ● Fax: (301) 768-4169

GEOTECHNICAL ● ENVIRONMENTAL ● DRILLING ● INSTRUMENTATION ● MATERIALS TESTING ● SPECIAL INSPECTIONS ● FACILITIES

July 28, 2022 (Revised)

Mr. Timothy J. Ramey, PE

WSP

13530 Dulles Technology Drive, Suite 300 Herndon, Virginia 20171

Reference: Geotechnical Engineering Report Fort Belvoir Kingman and Walker Gates Federal Aid Project No. VA ST FB_KNGMN/WLKR_GTS Fairfax County, Virginia DMY Project No. 01.04361.01

Dear Mr. Ramey:

DMY Engineering Consultants Inc. (DMY) is pleased to submit this report of our geotechnical exploration for the above-referenced project. This report presents a review of the information provided to us, a discussion of the site and subsurface conditions encountered, and our geotechnical recommendations.

This report was revised to address VDOT NOVA Materials Division’s comments dated April 9, 2021 and January 20, 2022 and Eastern Federal Lands Highway Division's comments on March 17, 2021 and February 23, 2022.

We appreciate the opportunity to be of service to you on this project and would be happy to discuss our findings with you. We look forward to serving as your geotechnical engineer on the remainder of this project and on future projects.

Respectfully, DMY ENGINEERING CONSULTANTS INC.

Jun Yao, Ph.D., EIT. Xin Chen, Ph.D., P.E., MBA.

Staff Geotechnical Engineer Vice President

Fort Belvoir Kingman and Walker Gates

DMY Project No. 01.04361.01

July 28, 2022 (Revised)

TABLE OF CONTENTS

1.0 PROJECT OVERVIEW

2.0 FIELD EXPLORATION AND LABORATORY TESTING

2.1. FIELD EXPLORATION

2.2. LABORATORY TESTING

3.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS

3.1. SITE GEOLOGY

3.2. SOIL SURVEY MAP

3.3. SUBSURFACE CONDITIONS

3.4. GROUNDWATER

3.5. EXISTING PAVEMENT

3.6. PAVEMENT CONDITIONS

4.0 GEOTECHNICAL AND PAVEMENT RECOMMENDATIONS

4.1. GENERAL PAVEMENT RECOMMENDATIONS

4.2. PAVEMENT DESIGN

4.3. FILL AND CUT SLOPES

4.4. SITE PREPARATION

4.5. EARTHWORK

4.6. SUBGRADE PREPARATION

4.7. UNSUITABLE SOILS

5.0 LIMITATIONS

APPENDIX A FIGURES

APPENDIX B FIELD OPERATIONS

APPENDIX C GROUND PENETRATION RADAR SURVEY RESULTS

APPENDIX D LABORATORY TESTING

APPENDIX E PAVEMENT DESIGN CALCULATIONS

APPENDIX F SLOPE STABILITY ANALYSIS RESULTS

APPENDIX G AS-BUILT PLANS

July 28, 2022 (Revised)

1.0 PROJECT OVERVIEW

The project site is located near Kingman and Walker Gates of Fort Belvoir in Fairfax County, Virginia.

Site Location Maps showing the approximate locations of the project for Kingman and Walker Gates are included in Appendix A. We understand that the project for Kingman Gate consists of increasing the capacity of left turn lane along the Fairfax County Parkway (VA Route 286) eastbound through the John

J. Kingman Road (referred as Kingman Road throughout this report) into Fort Belvoir’s Kingman Gate to reduce occurrence of queuing of left turning vehicles into the main through lane on eastbound. The project for Walker Gate consists of increasing the capacity of left turn lane along Mount Vernon Memorial

Highway (VA Route 235) through the Mount Vernon Road into Fort Belvoir’s Walker Gate to reduce occurrence of queuing of left turning vehicles into the main through lane on westbound. To accommodate the capacity increase, roadway widening along Fairfax County Parkway eastbound, Kingman Road and

Mount Vernon Memorial Highway is proposed. In addition, shared use path and trail are proposed along

Kingman Road as part of the improvement.

The description of the proposed project given above is based on the information provided to us by WSP and information gathered during our site reconnaissance. If any of the assumptions or project information is incorrect, DMY should be informed so that we may revise our geotechnical recommendations, if necessary.

2.0 FIELD EXPLORATION AND LABORATORY TESTING

2.1. FIELD EXPLORATION

Our original field exploration consisted of drilling eight (8) Standard Penetration Test (SPT) borings (KG-

B-01 through KG-B-05; WG-B-01 through WG-B-03) and fourteen (14) pavement cores (KG-PC-01 through KG-PC-10; WG-PC-01 through WG-PC-03; WG-B-02). Per VDOT reviewer’s comments dated

September 25, 2020, DMY drilled additional sixteen (16) SPT borings (KG-B-06 through KG-B-15; WG-

B-04 through WG-B-09). The boring locations were chosen by DMY and approved by WSP. DMY personnel located those borings and coring locations in the field based on visual reference to the existing site features. The as-drilled locations were surveyed by Rice Associates and coordinates & elevations were provided to DMY. The locations of the borings and pavement cores are shown on the Boring and

Pavement Core Location Plan included in Appendix A.

The SPT borings were drilled by truck- or track-mounted CME 45 and 55 drill rigs using the hollow stem auger method with 3.25-inch I.D. augers. Groundwater levels, where encountered, were measured at each boring location at the time of drilling. Groundwater measurement at 24 hours after drilling completion was not measured due to public safety concern. Upon completion of the field exploration, boreholes were backfilled with auger cuttings. Pavement core locations and borings drilled in the existing paved area were patched with quick-set concrete mix. The field exploration procedures are included in

Appendix B.

July 28, 2022 (Revised)

Following field operations, the soil samples were transported to our laboratory for further analysis and testing. The samples will be stored in our laboratory for a period of 90 days from the submittal date of this report. After this period, the samples will be discarded unless we are instructed otherwise.

In addition to SPT borings and pavement cores, Ground Penetration Radar (GPR) survey was performed to determine the pavement thickness of existing Kingman Road within project limits. The GPR survey was performed by using Geophysical Survey Systems, Inc. (GSSI) SIR-3000 GPR unit walking along the centerline of each lane with a 1500 megahertz (MHz) frequency antenna. Coordinates of endpoints, borings, and other site features were captured with Topcon HiperGA Real Time Kinematic Global

Positioning System (RTK GPS). Figure 1 in Appendix C shows a map of GPR survey line locations on the aerial view photos. The six GPR profiles were identified by their lane and corresponding field file number.

2.2. LABORATORY TESTING

Representative soil samples were selected and tested to verify field classifications and to determine pertinent engineering properties. The tests were performed in accordance with applicable ASTM, AASHTO, and/or VTM standards and VDOT MOI Chapter III. The table below is a summary of the laboratory testing program. The laboratory testing results are included in Appendix D.

Table 2-1: Summary of Laboratory Tests

Lab Test Test Method Number of Tests

Natural Moisture Content AASHTO T-265 141

Atterberg Limits AASHTO T-89 & T-90 32

Grain Size Analyses AASHTO T-88 32

Standard Proctor VTM-1 10

CBR VTM-8 10

Direct Shear Test ASTM D3080 1

3.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS

3.1. SITE GEOLOGY

Based on the review of the Geologic Map of Virginia (1993) published by Virginia Division of Mineral

Resources, the project site is located within the Coastal Plain Physiographic Province of Virginia. The project site at Kingman and Walker Gates are underlain by early Cretaceous-aged Potomac Group (Kp) and middle Pleistocene Shirley Formation (Qsh), respectively. The Potomac Group soils in this area consist of very light gray to pinkish-gray, medium to very coarse sand, green clay and clayey sand, and dark-yellowish-brown to olive-gray sandy silt and clay. Shirley Formation consists of light- to dark-gray, bluish-gray and brown sand, gravel, silt, clay, and peat.

July 28, 2022 (Revised)

3.2. SOIL SURVEY MAP

The project site at Kingman Gate is mapped as (95) Urban Land, (48) Gunston silt loam and (91)

Sassafras – Marumsco complex according to the 2011 Official Soil Maps of Fairfax County. (95) Urban

Land, (48) Gunston silt loam and (91) Sassafras – Marumsco complex are classified as Soil Problem

Class IVB, III and III, respectively, in the Description & Interpretative Guide to Soils in Fairfax County, published by Fairfax County Public Works and Environmental Services and Northern Virginia Soil and

Water Conservation District in April 2008 and revised in August 2011.

The project site at Walker Gate is mapped as (95) Urban Land, (77) Mattapex loam, (46) Grist Mill -

Mattapex complex, and (43) Grist Mill - Gunston complex according to the 2011 Official Soil Maps of

Fairfax County. (95) Urban Land, (77) Mattapex loam, (46) Grist Mill - Mattapex complex, and (43) Grist

Mill - Gunston complex are classified as Soil Problem Class IVB, II, IVB and IVA, respectively, in the

Description & Interpretative Guide to Soils in Fairfax County, published by Fairfax County Public Works and Environmental Services and Northern Virginia Soil and Water Conservation District in April 2008 and revised in August 2011.

Detailed descriptions of aforementioned soil units can be found in this publication. The following paragraphs are excerpts from this publication.

(95) Urban Land - This unit consists entirely of man-made surfaces such as pavement, concrete or rooftop.

Urban land is impervious and will not infiltrate stormwater. All precipitation landing on Urban Land will be converted to runoff. Urban Land units lie atop development disturbed soils. Ratings for this unit are not provided.

(48) Gunston silt loam - This silty and clayey soil occurs on flat portions of the Coastal Plain in Mason

Neck. The topsoil is typically grey silt loam while the subsoil consists of deep moderately plastic clays.

Bedrock is greater than 20 feet below the surface. The seasonal high water table ranges from 10 inches to 2½ feet below the surface. Foundation support is poor because of the high water table, soft soil and plastic clays. Extensive foundation drains (both exterior and interior), waterproofing and surface grading are necessary to prevent wet basements. Suitability for septic tanks and infiltration trenches is poor because of the high water table and slow permeability. Surface grading and subsurface drainage are needed to prevent wet yards.

(91) Sassafras – Marumsco complex - This soil complex occurs along steeper slopes separating the high elevation and low elevation areas of the Coastal Plain and along slopes bordering larger Coastal Plain streams. This complex was formerly referred to as Marine Clay. Dry, sandy and gravelly Sassafras material is stratified with layers of thick, highly plastic marine clays. Water perches on top of the clay layers and springs can form where the clay strata come to the surface. Depth to the perched water table is variable depending on the specific stratification. This soil is highly variable. Unstable slopes can lead to serious land slippage or landslides. Depth to bedrock is greater than 50 feet. Foundation support is poor because of the potential perched water table, unstable slopes and plastic clays. Intensive geotechnical analysis is needed before construction commences. Suitability for septic drainfields and infiltration trenches is poor because of the high water table, plastic clays and unstable slopes.

July 28, 2022 (Revised)

(77) Mattapex loam - This soil occurs on uplands in sand, silt, and clay sediments of the lower Coastal

Plain. Loams and clay loams overlie very sandy layers. The seasonal high water table is between 2 and

3 feet below the surface. Depth to hard bedrock is typically greater than 200 feet. Foundation support may be marginal because of occasional soft soil and seasonal saturation. Foundation drains and waterproofing are needed to prevent wet basements. Grading and subsurface drainage are often necessary to eliminate wet yards. Suitability for septic drainfields and infiltration trenches is poor because of the high water table.

(46) Grist Mill - Mattapex complex - This complex is a mixture of the development-disturbed Grist Mill soil and the natural Mattapex soil. The complex occurs in low elevation areas of the Coastal Plain that have been developed but retain a good portion of undisturbed soil. Grist Mill soil will be clustered around foundations, streets, sidewalks, playing fields and other graded areas. Mattapex soil will be found under older vegetation in ungraded back and front yards and common areas. For a description of the two soils that make up this map unit, please see (40) Grist Mill and (77) Mattapex.

(43) Grist Mill - Gunston complex - This complex is a mixture of the development-disturbed Grist Mill soil and the natural Gunston soil. The complex occurs in areas of Mason Neck that have been developed but retain a good portion of undisturbed soil. Grist Mill soil will be clustered around foundations, streets, sidewalks, playing fields and other graded areas. Gunston soil will be found under older vegetation in ungraded back and front yards and common areas. For a description of the two soils that make up this map unit, please see (40) Grist Mill and (48) Gunston.

(40) Grist Mill - This soil consists of sandy, silty and clayey sediments of the Coastal Plain that have been mixed, graded and compacted during development and construction. Characteristics of the soil can be quite variable depending on what materials were mixed in during construction. The subsoil is generally a clay loam, but can range from sandy loam to clay. The soil has been compacted, resulting in high strength and slow permeability. The soil is well drained and depth to bedrock is greater than 20 feet below the surface. In most cases, foundation support is suitable assuming that the soil is well compacted and contains few clays. Because of the slow permeability, suitability for septic drainfields is poor and for infiltration trenches is marginal. Grading and subsurface drains may be needed to eliminate wet yards caused by the slow permeability. This soil is found in low elevation developed areas of the Coastal Plain.

3.3. SUBSURFACE CONDITIONS

The subsurface conditions encountered at the locations explored are shown in the boring logs presented in Appendix B. The records represent our interpretation of the subsurface conditions based on visual observations and laboratory testing of the soil samples collected. The lines designating the interfaces between various strata on the boring logs are approximate, as the actual transitions between soil strata are often gradual. In the absence of foreign substances, it is difficult to distinguish between natural soils and clean soil fills. Although individual test borings are representative of the subsurface conditions at the boring locations on the dates shown, they are not necessarily indicative of the subsurface conditions at other locations or at other times.

July 28, 2022 (Revised)

Kingman Gate

Approximately 2.4 to 6 inches of asphalt and 1 to 8.4 inches of aggregate base were encountered at

Borings KG-B-01 to KG-B-03, KG-B-06 to KG-B-12, and KG-B-15. Approximately 2 to 4 inches of topsoil were encountered at Boring KG-B-05, KG-B-13 and KG-B-14. Topsoil encountered is typically a dark colored soil material containing roots, fibrous matter, and/or other organic components, and is generally unsuitable for engineering purposes. Although the measured topsoil depths were found to be of minimal thickness in the borings during our exploration, the topsoil may be thicker in unexplored areas, particularly in vegetated undisturbed areas. DMY has not performed any laboratory testing to determine the organic content or other horticultural properties of the observed surficial soil material; therefore, the term topsoil is not intended to indicate suitability for landscaping and/or other purposes.

Below the surficial materials, two strata were encountered at the borings within boring termination depths.

The soil strata observed in the exploration at the site include man-made fill and Coastal Plain soils of

Potomac Group. The following table summarizes the generalized soil descriptions from the available subsurface exploration.

Table 3-1: Summary of Subsurface Conditions at Kingman Gate

Geologic

Strata Soil Description

USCS

Classification SPT N-values

Primary Secondary Min Max

Fill

Generally composed of soils obtained from nearby natural soils. The soils from this stratum generally retain some of the properties of the parent soil, but may contain debris and organic material.

SC/SM/CL GM/ML 3 43

Potomac Coastal Plain soils that belong to the

Potomac Group.

CH/CL/SC SM 2 50/4”

Walker Gate

Approximately 5 to 7.5 inches of asphalt was encountered at Borings WG-B-02 and WG-B-09.

Approximately 2 to 5 inches of topsoil were encountered at Borings WG-B-01 and WG-B-03 to WG-B-08.

Topsoil encountered is typically a dark colored soil material containing roots, fibrous matter, and/or other organic components, and is generally unsuitable for engineering purposes. Although the measured topsoil depths were found to be of minimal thickness in the borings during our exploration, the topsoil may be thicker in unexplored areas, particularly in vegetated undisturbed areas. DMY has not performed any laboratory testing to determine the organic content or other horticultural properties of the observed surficial soil material; therefore, the term topsoil is not intended to indicate suitability for landscaping and/or other purposes.

Below the surficial materials, only one stratum, which was identified as man-made fill, was encountered at the borings within boring termination depths. The following table summarizes the generalized soil descriptions from the available subsurface exploration.

July 28, 2022 (Revised)

Table 3-2: Summary of Subsurface Conditions at Walker Gate

Geologic

Strata Soil Description

USCS

Classification SPT N-values

Primary Secondary Min Max

Fill

Generally composed of soils obtained from nearby natural soils. The soils from this stratum generally retain some of the properties of the parent soil, but may contain debris and organic material.

CL SM 3 28

3.4. GROUNDWATER

Groundwater was encountered at Boring KG-B-03, KG-B-06 and KG-B-11 at depth of 29.0 feet, 6.3 feet and 8.7 feet during the time of drilling, respectively. It should be noted that groundwater levels fluctuate with seasonal and climatic variations and may be different at other times and locations than those stated in this report.

3.5. EXISTING PAVEMENT

We obtained and reviewed the as-built plans from VDOT. The following table summarizes the available existing pavement information at the project site near Kingman Gate. These as-built roadway plans and typical section sheets are included in Appendix G.

Table 3-3: Pavement Information from As-Built Plans

Location Pavement Section Source of

Information

Fairfax County Parkway Eastbound Main Lane

1.5 inches Surface Course - Asphalt Concrete

1995 Plans

2.0 inches Intermediate Course - Asphalt Concrete

5.0 inches Base Course - Asphalt Concrete

3.0 inches Asphalt-Stabilized Open-Graded Material

8.0 inches Subbase - Cement-Treated Aggregate Material

Fairfax County Parkway Eastbound Shoulder

3.0 inches of Surface Course - Asphalt Concrete

Kingman Road

1.5 inches Surface Course - Asphalt Concrete

5.5 inches Base Course - Asphalt Concrete

6.0 inches Subbase - Cement-Treated Aggregate Material

July 28, 2022 (Revised)

At Kingman Gate, seven (7) pavement cores (KG-PC-01 through KG-PC-07) were obtained along Fairfax

County Parkway eastbound and three (3) pavement cores (KG-PC-08 through KG-PC-10) were obtained along Kingman Road. At Walker Gate, four (4) pavement cores (WG-PC-01 through WG-PC-03 and

Pavement Core at WG-B-02) were obtained along Mount Vernon Memorial Highway. The pavement core photos and information are included in Appendix B. Upon completion of the field exploration, all pavement core holes were patched with quick-set concrete mix. Following field operations, the pavement cores were transported to our laboratory for further analysis and documentation. Table below summarize the pavement thickness information at boring and pavement coring locations.

Table 3-4: Summary of Pavement Information at Boring & Coring Locations

KG-PC-01 103+00 5.75 LT Right Lane 9.0 2.5 2.5 6.0

CTA broke into several pieces and not fully recovered

KG-PC-02 105+00 22.0 LT Left Lane 9.5 2.5 0.0 6.0

KG-PC-03 109+25 28.25 LT Left Lane 10.5 3.0 0.0 6.0

KG-PC-04 110+90 51.5 LT

Inside Left

Turn Lane

12.0 0.0 0.0 6.0

KG-PC-05 115+00 11.75 LT Right Lane 8.8 2.7 0.0 6.0

KG-PC-06 117+00 0.0

Right

Shoulder

9.0 0.0 0.0 6.0

Top 3.5" of AC broke into 3 pieces due to surface cracks;

Bottom 5.5" of AC was intact

KG-PC-07 119+00 18.25 LT Left Lane 11.5 0.0 0.0 6.0

KG-B-01 104+00 3.75 RT

Right

Shoulder

5.0 0.0 0.0 3.0

Augered through existing pavement

KG-B-02 106+00 0.0

Right

Shoulder

6.0 0.0 0.0 4.0

Augered through existing pavement

KG-B-03 113+70 1.0 LT

Right

Shoulder

2.4 0.0 0.0 6.0

Augered through existing pavement

KG-B-06 108+05 7.5 RT

Right

Shoulder

3.5 0.0 0.0 2.5

Augered through existing pavement

KG-B-07 110+13 7.5 RT

Right

Shoulder

5.0 0.0 0.0 3.0

Augered through existing pavement

KG-B-08 111+18 7.5 RT

Right

Shoulder

5.0 0.0 0.0 4.0

Augered through existing pavement

KG-B-09 112+55 3.0 LT

Right

Shoulder

4.0 0.0 0.0 3.6

Augered through existing pavement

KG-B-10 115+75 3.0 RT

Right

Shoulder

5.0 0.0 0.0 1.0

Augered through existing pavement

KG-B-11 117+75 6.25 RT

Right

Shoulder

5.0 0.0 0.0 3.0

Augered through existing pavement

Fairfax County Parkway Eastbound (Kingman Gate)

OGDL

Thickness

(inches)

CTA

Thickness

(inches)

GAB

Thickness

(inches)

Remarks Boring/Core

Number Station

Offset

(feet)

Existing

Lane ID

AC

Thickness

(inches)

July 28, 2022 (Revised)

Table 3-4: Summary of Pavement Information at Boring & Coring Locations (Continues)

Kingman Gate: Along Fairfax County Parkway eastbound, Pavement Cores KG-PC-01 through KG-PC-

07 indicated asphalt concrete (AC) thicknesses ranging from 8.8 to 12.0 inches, with an average thickness of about 10.0 inches. Approximate 2.5 to 3.0 inches of Asphalt-Stabilized Open-Graded

Material (ASOGM) was encountered beneath the asphalt concrete at KG-PC-01 through KG-PC-03 and

KG-PC-05. Approximate 2.5 inches of loosely bound Cement-Treated Aggregate (CTA) was also encountered beneath the ASOGM at KG-PC-01. Graded Aggregate Base (GAB) with thicknesses of 6 inches was encountered beneath the AC, ASOGM or CTA in these core locations. Along Kingman Road, Pavement Cores KG-PC-08 through KG-PC-10 indicated asphalt concrete (AC) thicknesses ranging from

2.5 to 5.5 inches, with an average thickness of 4.4 inches. Approximate 3.0 inches of Cement-Treated

Aggregate (CTA) was also encountered beneath the AC at KG-PC-09 and KG-PC-10. Graded Aggregate

Base (GAB) with thicknesses of 3 to 6 inches was encountered beneath the AC or CTA in these core locations.

Walker Gate: Along Mount Vernon Highway, Pavement Cores WG-PC-01 through WG-PC-03 and WG-

B-02 indicated asphalt concrete (AC) thicknesses ranging from 7.0 to 9.0 inches, with an average thickness of about 7.9 inches. No historic plan inside the project limit of Walker Gate was available from

VDOT for review.

KG-PC-08 204+40 23.5 RT

Northbound

Right Lane

5.5 0.0 0.0 6.0

KG-PC-09 205+25 34.75 LT

Southbound

Right Lane

2.5 0.0 3.0 3.0

KG-PC-10 207+25 23.25 LT

Southbound

Left Lane

5.2 0.0 3.0 4.0

KG-B-12 204+25 19.5 RT

Northbound

Right Lane

5.0 0.0 0.0 8.2

Augered through existing pavement

KG-B-15 207+25 35.5 LT

Southbound

Right Lane

6.0 0.0 3.0 8.4

Augered through existing pavement

WG-PC-01 305+50 29.0 LT

Westbound

Through Lane

7.8 0.0 0.0 0.0

WG-B-02 310+50 16.75 LT

Eastbound

Lane

7.5 0.0 0.0 0.0

WG-PC-02 315+50 21.5 LT

Eastbound

Lane

7.0 0.0 0.0 0.0

WG-PC-03 320+50 9.0 LT

Eastbound

Lane

9.0 0.0 0.0 0.0

WG-B-09 322+50 9.5 RT

Eastbound

Right Turn

Lane

5.0 0.0 0.0 4.9 Augered through existing pavement

John J. Kingman Rd (Kingman Gate)

Mount Vernon Memorial Highway (Walker Gate)

OGDL

Thickness

(inches)

CTA

Thickness

(inches)

GAB

Thickness

(inches)

Remarks Boring/Core

Number Station

Offset

(feet)

Existing

Lane ID

AC

Thickness

(inches)

July 28, 2022 (Revised)

Kingman Road (from GPR results): Figure 2 through 7 in Appendix C shows the pavement profile from

GPR results for Kingman Road within the project limits. The approximate depths of interpreted layers including asphalt concrete (AC), Graded Aggregate Base (GAB) and/or Cement-Treated Aggregate (CTA) were plotted against the station numbers on each scanned lane. It should be noted there is no clear boundary between GAB and CTA due to similarity of electromagnetic material property between GAB and CTA. It should be also noted that there is a signal disturbance near Station 202+90 due to possible utility across the road. Below table is a summary of the estimated AC, GAB/CTA thicknesses in each lane.

Table 3-5: Summary of Estimated Pavement Profile Thickness from GPR Results for Kingman Rd

Lane ID AC Thickness (inch) GAB and/or CTA Thickness (inch)

Min Max Mean Min Max Mean

Northbound

Right Turn

Lane

4.0 6.0 5.0 3.0 12.0 8.0

Northbound

Right Lane

4.0 8.0 5.5 3.0 12.0 7.5

Northbound

Left Lane

4.0 8.0 5.0 5.5 13.0 7.0

Southbound

Left Turn

Lane

3.0 8.0 5.0 3.0 9.0 7.0

Southbound

Left Lane

2.0 6.0 3.5 3.0 10.5 7.0

Southbound

Right Lane

3.0 6.0 5.0 5.0 12.5 8.0

3.6. PAVEMENT CONDITIONS

We performed pavement condition survey and patching survey for the existing pavement within the project limits. The select photos of our pavement condition survey are included in Appendix B. Below is the summary of our pavement condition survey results.

Kingman Gate

Fairfax County Parkway eastbound main through and left turn lanes is in satisfactory to fair condition with low to moderate severity fatigue cracking, low to moderate severity longitudinal and transverse cracking, low to moderate severity edge cracking and a moderate severity pothole. Fairfax County Parkway eastbound right turn lane and right shoulder are in fair to very poor condition with moderate to high severity longitudinal and transverse cracking, moderate severity block cracking. We also observed tension crack and shoulder drop-off (about 8 inches) approximately between Stations 113+50 and

114+10. The tension crack and shoulder drop-off typically indicates that the slope is distressed and has sign of potential slope instability.

Kingman Road within the project limit is in very poor to serious condition with moderate to high severity fatigue cracking, high severity longitudinal cracking, rutting, potholes with patching and significant patch

July 28, 2022 (Revised) deterioration. The photos of pavement conditions on Fairfax County Parkway EB and Kingman Road are included in Appendix B.

Walker Gate

Mount Vernon Memorial Highway eastbound and westbound are in satisfactory to good condition with low to moderate severity fatigue cracking and low severity edge cracking which were mainly observed on eastbound between Stations 303+50 and 304+50. Other sections within the project limit show no or little pavement distress.

4.0 GEOTECHNICAL AND PAVEMENT RECOMMENDATIONS

4.1. GENERAL PAVEMENT RECOMMENDATIONS

Based on our pavement patch survey per VDOT MOI Chapter VI Section 601.03 Patching Survey

Guidelines and our pavement analyses, we recommend mill & overlay for Fairfax County Parkway eastbound main through and left turn lanes and full depth patches (new pavement) for Fairfax County

Parkway eastbound right turn lane and right shoulder and Kingman Road northbound and southbound.

4.2. PAVEMENT DESIGN

We performed pavement design for new pavement (widening area) and mill & overlay (existing pavement) per VDOT Manual of Instructions (MOI) Chapter VI Section 603 Guidelines for 1993 AASHTO Pavement

Design. Detailed pavement design calculations are included in the Appendix E of this report. The design traffic data for the proposed improvement is provide by WSP and is summarized in Table 4-1.

Table 4-1: Design Traffic Data

Fairfax County

Parkway Eastbound Kingman Road

Mount Vernon

Memorial Highway

New Pavement Design Life

(Years) 30 30 30

Overlay Design Life (Years) 12 12 12

Initial Design Year 2022 2022 2022

Two-way AADT (Initial) 23,980 18,125 14,211

Annual Growth Rate 0.7% 0.7% 0.5%

Directional Ratio (Pavement

Design) 54.9% 50.0% 58.5%

Percent Cars/Passenger

Vehicles 99% 98% 99%

Percent Single Unit Trucks 1% 1% 1%

Percent Tractor Trailer Trucks 0% 1% 0%

July 28, 2022 (Revised)

We collected bulk samples from eight (8) locations and performed California Bearing Ratio (CBR). Table

4-2 shows the laboratory results. The design CBR values are selected as two-thirds of the average laboratory CBR values per VDOT MOI.

Table 4-2: Summary of Laboratory and Design CBR Values

Roadway ID Laboratory CBR Values Design CBR

Values

Reference

Boring IDs Min Max Average

Fairfax County

Parkway

Eastbound

10.0 14.2 12.6 8.4

KG-B-01

KG-B-02

KG-B-03

Kingman

Road

5.4 14.2 9.2 6.1

KG-B-04

KG-B-05

KG-B-14

Mount Vernon

Memorial

Highway

5.1 16.9 10.4 6.9

WG-B-01

WG-B-02

WG-B-03

WG-B-08

Below are our pavement recommendations. The pavement widening should be performed in accordance with VDOT standard detail WP-2 for asphalt pavement widening. VDOT standard UD-4 edge drains should be installed beneath the curb and gutter of all new pavements. The underdrain pipes should be either connected to existing underdrain or storm structures.

Table 4-3: New Pavement or Full Depth Patch

Location Pavement Section

Fairfax County Parkway Eastbound

Surface Course (SM-9.5E) = 2.0” Intermediate Course (IM-19.0D) = 2.0”

Base Course (BM-25.0D) = 5.0” Drainage Layer (Asphalt-Stabilized Open-Graded Materiala) = 3.0”

Subbase Course (Cement-Treated Aggregate Material Size 21A) = 8.0”

Kingman Road

Surface Course (SM-9.5E) = 2.0” Intermediate Course (IM-19.0D) = 2.0”

Base Course (BM-25.0D) = 3.0” Subbase Course (Cement-Treated Aggregate Material Size 21A) = 8.0”

Mount Vernon Memorial Highway Eastbound

Surface Course (SM-9.5E) = 3.0”b Base Course (BM-25.0D) = 5.0”

Subbase Course (Aggregate Base No. 21B) = 6.0” c Subbase Course (Cement-Treated Aggregate Material Size 21A) = 6.0” c

Note: a. Asphalt-Stabilized Open-Graded Material shall comply with VDOT Road and Bridge Specifications

Section 313.

b. The surface course shall be placed in two equal lifts with tack coat between lifts.

c. Aggregate Base No. 21B shall be for the drainage low side; while Cement-Treated Aggregate

Material Size 21A shall be used for the drainage high side;

July 28, 2022 (Revised)

Table 4-4: Mill & Overlaya

Fairfax County Parkway Eastbound Main

Through and Left Turn Lanes

Mill 2.0 inches and replace with 2.0 inches SM 9.5E

Kingman Road

Based on the existing pavement thickness (varying from 2.0” to 8.0”) and our pavement analysis, we recommend that the existing pavement be re-constructed. This is due to two reasons: (1) traffic; (2) existing pavement is insufficient for mill & overlay.

Mount Vernon Memorial Highway Eastbound

Mill 3.0 inches and replace with 3.0 inches SM 9.5Eb

Note: a. The tack coat shall be applied between Asphalt lifts, to all vertical faces and on top of milled existing

Asphalt. The tack coat shall comply with VDOT Road and Bridge Specification Section 310.

b. The surface course shall be placed in two equal lifts with tack coat between lifts.

4.3. FILL AND CUT SLOPES

VDOT MOI Chapter III defines critical slope as “any slope that is greater than 25 feet in height, affects or supports a structure (i.e. irrespective of height), impounds water or whose failure would result in significant cost for repair, or damage to private property”. Based on the plans and cross sections prepared by WSP dated August 20, 2020, the proposed slope heights are less than 25 feet and are not considered critical slopes. We have performed slope stability analyses at three selected locations as summarized in Table 4-5.

Table 4-5: Slope Stability Analysis Sections

Slope Location

Analyzed

Cross-

Section

(Station)

Maximum

Slope Height

(feet)

Factor of

Safety

(FS)

Reference

Borings

Fairfax County Parkway Eastbound

Stations 102+25 to 108+00

106+00 10.2 1.3 KG-B-02

Fairfax County Parkway Eastbound

Stations 112+75 to 119+00

113+75 12.7 1.0 KG-B-03

Kingman Road Southbound

Stations 202+00 to 202+50

202+25 10.0 1.8 KG-B-05

The slope stability analyses were performed by Slide 7.0 computer program using a limit equilibrium analysis method (e.g., Bishop Simplified). The factor of safety (F.S.) against slope instability computed by the program is defined as the ratio of the sum of the resisting moments (or forces) divided by the sum

July 28, 2022 (Revised) of the driving moments (or forces) along a specified potential slip surface. During this analysis, numerous conditions and potential slip surfaces were analyzed. The computer outputs show the most critical surfaces and their safety factors. The results of the slope global stability analyses are summarized in

Table 4-5. The slope stability analysis results are included in Appendix F.

The slope stability analysis results show the factors of safety are below 1.3 (from Station 112+75 to

119+00) and barely meet 1.3 (from Station 102+25 to 108+00) for both proposed and existing slope at

Fairfax County Parkway eastbound. The results are consistent with the field observation of distressed slope condition with high severity pavement distress. We recommend the section of existing slope from

Stations 102+25 to 108+00 and 112+75 to 119+00 be removed and reconstructed with new fill materials and riprap slope toe to meet the minimum required factor of safety of 1.3 per Figure 2 in Appendix A.

VDOT Select Material Type II or III and VDOT Riprap Class I should be used as the new embankment fill and riprap materials, respectively in accordance with Section 207 – Select Material and Section 204 –

Stone for Masonry, Riprap, Porous Backfill and Gabions of the VDOT Road and Bridge Specifications.

VDOT Class B Geotextile should be placed between the riprap and soils in accordance with Section 245

– Geosynthetics and Low Permeability Liners of the VDOT Road and Bridge Specifications.

4.4. SITE PREPARATION

Site preparation should consist of any proposed demolition, removing existing underground utilities, existing structures, topsoil and vegetation, and any other soft or unsuitable material from the proposed construction areas. Utilities such as pipes should be removed entirely or abandoned by filling the pipe with grout to prevent future migration of soils into the pipe. Voids resulting from the removal of tree stumps should be filled with compacted structural fill. Disposal of demolition debris should be performed in accordance with local, state and federal regulations. Additional requirements included in Section 301

– Clearing and Grubbing of the VDOT Road and Bridge Specifications should be followed.

4.5. EARTHWORK

The earthwork for the proposed roadway and sidewalk construction should be performed in accordance with Section 303 – Earthwork of the VDOT Road and Bridge Specifications. Additional site specific recommendations are discussed in the following paragraphs.

4.6. SUBGRADE PREPARATION

Following the site preparation and any required excavation, the newly exposed roadway and sidewalk subgrade should be evaluated by an authorized representative of the Geotechnical Engineer of Record.

During this evaluation, we recommend that all subgrade areas be proof-rolled using a fully loaded tandem axle dump truck (10-ton minimum) or similar rubber-tired vehicle. The proofrolling should be performed in such a pattern that the entire subgrade areas are loaded with at least one pass. Areas that are not accessible to proofrolling may be evaluated using other suitable methods such as a steel probe rod.

If the subgrade exhibits excessive deflections or pumping when proof-rolled or soft subgrade is detected by probing, an appropriate remedial measure would be recommended by the Geotechnical Engineer of

Record at that time. Potential problem subgrade areas as identified by this soil investigation and the

July 28, 2022 (Revised) recommended remedial measures are detailed in the following paragraphs. The stabilized subgrade areas should be again evaluated and approved by the Geotechnical Engineer of Record prior to fill placement or pavement installation.

4.7. UNSUITABLE SOILS

Unsuitable soils generally include soils that have excessive moisture, high plasticity (Liquid Limits greater than 50%), soils with low SPT N-values (less than 5 bpf), low CBR value (CBR < 5), high swell (swell >5%), and soils containing excessive debris and organics. The types and recommended treatment methods of the unsuitable soils are discussed in detail in the following paragraphs.

Highly Plastic or High Swell (>5%) Subgrade Soils: Highly plastic or high swell soils were not encountered at the proposed subgrade elevations in any of the roadway borings.

Low CBR, Soft/Loose, and Excessively Moist Subgrade Soils: Low CBR (< 5) soils were not encountered at the proposed subgrade elevations in any of the roadway borings while soft/loose soils (SPT N-values less than 5 bpf) were encountered in Borings KG-B-03 and WG-B-07 within the proposed subgrade elevation. In addition, the soils at/near the proposed subgrade along the project alignment were found to be excessively moist at the time of field exploration and this condition has the potential to cause pumping problems during subgrade and base construction. If soft/loose unsuitable soils are encountered at locations shown in Table B2 of Appendix B (e.g., Station 318+50 on Mount Vernon Hwy), we recommend that 3 feet of subgrade soils be undercut and replaced with compacted VDOT Select Material

Type I with a minimum CBR value of 30 in accordance with Section 207 – Select Material of the VDOT

Road and Bridge Specifications. If unsuitable subgrade soils with excessive moisture are encountered, we recommend that 3 feet of subgrade soils be undercut and replaced with compacted VDOT Select

Material Type I with a minimum CBR value of 30 or dry up the top 2 feet of subgrade soils beneath the proposed pavement using mechanical means to within 120% of the optimum moisture content and recompact in place as suggested in Table B2 of Appendix B. Depending on the weather conditions at the time of subgrade construction, the locations and quantities of the excessively moist subgrade soils may be different and may be adjusted by the Geotechnical Engineer of Record or an authorized representative at the time of construction.

5.0 LIMITATIONS

The recommendations provided are based in part on project information provided to us and are only applied to the specific project and site discussed in this report. If the project information section in this report contains incorrect information or if additional information is available, DMY should be contacted to review our recommendations. We can then modify our recommendations for the proposed project.

Regardless of the thoroughness of a subsurface investigation, there is always a possibility that subsurface conditions may vary from those documented during a subsurface exploration at specific locations. In addition, the construction process itself may alter subsurface conditions. Therefore, experienced geotechnical personnel should be engaged to observe and document the construction procedures used and the conditions encountered. Unanticipated conditions and inadequate procedures

July 28, 2022 (Revised) should be reported to the design team along with timely recommendations. We recommend that DMY be retained to provide this service based upon our familiarity with the project, the subsurface conditions, and the intent of the recommendations.

We have prepared this report for use by the design professionals for design purposes in accordance with generally accepted geotechnical engineering practices. No other warranty, expressed or implied, is made as to the professional advice included in this report.

APPENDIX A FIGURES

COPYRIGHT GOOGLE

FORT BELVOIR KINGMAN AND WALKER GATES

FAIRFAX COUNTY, VIRGINIA

DATE:

8/22/2020

SCALE:

1"=2000'

DRAFTED BY:

JY

CHECKED BY:

XC

PROJECT NO.:

01.04361.01

FIGURE NO.:

1A

DMY ENGINEERING CONSULTANTS INC .

4170 LAFAYETTE CENTER DR, SUITE 500

CHANTILLY, VIRGINIA 20151

PHONE: (703) 665-0586

FAX: (301) 768-4169

SITE LOCATION MAP

Site Location (Kingman Gate)

COPYRIGHT GOOGLE

FAIRFAX COUNTY, VIRGINIA

DATE:

8/22/2020

SCALE:

1"=2000'

DRAFTED BY:

JY

CHECKED BY:

XC

PROJECT NO.:

01.04361.01

FIGURE NO.:

1B

DMY ENGINEERING CONSULTANTS INC .

4170 LAFAYETTE CENTER DR, SUITE 500

CHANTILLY, VIRGINIA 20151

PHONE: (703) 665-0586

FAX: (301) 768-4169

SITE LOCATION MAP

Site Location (Walker Gate)

VA.

ROUTE PROJECT

VA.

REVISED

STATE

SHEET NO.

dKNGWLK03.dgn

Plotted By: buchanantm4:10:24 PM

1/25/2021

PROJECT SHEET NO.

DESIGN FEATURES RELATING TO CONSTRUCTION

OR TO REGULATION AND CONTROL OF TRAFFIC

MAY BE SUBJECT TO CHANGE AS DEEMED

NECESSARY BY THE GOVERNMENT

SURVEYED BY, DATE

PROJECT MANAGER

SCALE

25' 50'

SUBSURFACE UTILITY BY, DATE

TIMOTHY J. RAMEY, PE (WSP USA, INC.)

EASTERN FEDERAL LANDS HIGHWAY DIVISON

WLKR GTS

VA ST FB_KNGMN /

WLKR GTS

VA ST FB_KNGMN /

RICE ASSOCIATES, (703) 968-3200, OCTOBER 2019, SUPPLEMENTED MAY 2020

RICE ASSOCIATES, (703) 968-3200, OCTOBER 2019

DESIGN SUPERVISED BY

DESIGNED BY MARTHA J. ALUNKAL, PE (WSP USA, INC.)

EDEN JEMAL, PE, PMP (703) 404-6323 (EFLHD)

Rap Rip

In

P l.

U n d e r d r a in

Rap

Rip

S ig n

Metal GuardRail

Asphalt Sidewalk

Gravel Shoulder

Gravel Shoulder

Metal GuardRail

In

P l.

U n d e r d r a in

In

P l.

U n d e r d r a in

Asphalt Shoulder

Gravel Shoulder

Asphalt Shoulder

In

P l.

U n d e r d r a in

DB 10132 Pg 1369 and Grading Esmt.

Ex. Temporary Construction

DB 10132 Pg 1369

Drainage Esmt.

Ex. Storm

RW Pin RW Pin RW Pin

UNITED STATES OF AMERICA

DB 1157 PG 163

TAX MAP# 115-2-01-0001

UNITED STATES OF AMERICA

DB 1157 PG 163

TAX MAP# 115-2-01-0001

Qwest Fi ber Duc t

Triple Left Turn Taper

500ft

12'

12'

4'

F

Legend:

C

F

Denotes Construction Limits in Cut

Denotes Construction Limits in Fill

Full-Depth Asphalt Pavement

FAIRFAX COUNTY PARKWAY EB (ROUTE 286)

FAIRFAX COUNTY PARKWAY WB (ROUTE 286)

F

CG-3 Required

Existing Edge Of Pavement

Alignment 286_BL

MGS GR within Limits of Project Existing Guardrail to be Replaced with

Existing Edge of Pavement

Proposed Edge of Travelway

Proposed Edge of Travelway

And R/W Line Existing Limited Access

And R/W Line Existing Limited Access

225ft

500ft

Triple Left Turn Storage Length

Sta. 102+18.50 Begin Project

9' Long Posts GR-MGS1 Required, 25.84' LT

Sta. 103+84.45 Begin Taper

57.00' LT

Sta. 106+09.45 End Taper

PAVED SHOULDER

Paved Shoulder Proposed Edge of

Shoulder Slope Transition

Fairfax County Trail

Connect to Existing Inlet

36.51' LT

Sta. 102+23.90 Mill and Overlay

1.06' LT

Sta. 102+22.66 Mill and Overlay

Riprap

Proposed R/W

Face of Guardrail CG-7 Required at

Full Depth Sawcut Required

Approximately Sta. 101+84.00 Limits of Project Starting at Replaced with MGS GR within Existing Guardrail to be

GR-MGS4 Required

Mill & Overlay (See Typical Sections)

* Design waiver for reduced taper length submitted with Intermediate Plans Submission

Graded Shoulder Existing Edge of

Denotes Proposed R/W

Construction Easement Denotes Proposed Temporary

Construction Easement Proposed Temporary

UD-4 Required

S T

A

+0

.0

M A

T C

H L

IN

E

S H

E E

T

Curve 286_BL_3

PI = 102+57.31

T = 38.81'

L = 77.61'

R = 4,220.00'

102+18.50PC =

PT = 102+96.11

P O

T

+0

.0

P C

+18 .5

P T

+9

.11

P C

+6

.9

E = Match Existing

V = 55 mph

15"

15"

3-2

3-3

3-1 3-4

CONSTRUCTION.

USED FOR ANY TYPE OF

UNAPPROVED AND ARE NOT TO BE

THESE PLANS ARE UNFINISHED AND

STA 100+00.00 TO STA 107+00.00

FAIRFAX COUNTY PARKWAY

PLAN

KINGMAN GATE

xchen Oval xchen Oval xchen Oval xchen Oval xchen Typewritten Text

KG-PC-01

xchen Typewritten Text

KG-PC-02

xchen Typewritten Text

KG-B-02

xchen Typewritten Text

KG-B-01

xchen Oval xchen Oval xchen Typewritten Text Soil Boring xchen Typewritten Text Pavement Cores

VA.

REVISED

STATE

dKNGWLK04.dgn

Plotted By: buchanantm4:10:44 PM

1/25/2021

PROJECT SHEET NO.

DESIGN FEATURES RELATING TO CONSTRUCTION

OR TO REGULATION AND CONTROL OF TRAFFIC

MAY BE SUBJECT TO CHANGE AS DEEMED

NECESSARY BY THE GOVERNMENT

SURVEYED BY, DATE

PROJECT MANAGER

SCALE

25' 50'

SUBSURFACE UTILITY BY, DATE

TIMOTHY J. RAMEY, PE (WSP USA, INC.)

EASTERN FEDERAL LANDS HIGHWAY DIVISON

WLKR GTS

VA ST FB_KNGMN /

WLKR GTS

VA ST FB_KNGMN /

RICE ASSOCIATES, (703) 968-3200, OCTOBER 2019, SUPPLEMENTED MAY 2020

RICE ASSOCIATES, (703) 968-3200, OCTOBER 2019

DESIGN SUPERVISED BY

DESIGNED BY MARTHA J. ALUNKAL, PE (WSP USA, INC.)

EDEN JEMAL, PE, PMP (703) 404-6323 (EFLHD)

D

Conc.

0. 5' Conc Curb

0. 5' Conc Curb

Metal GuardRail Metal GuardRail

Asphalt Sidewalk 6' Chain Link Fence

8' Chain Link Fence 6' Chain Link Fence

S ig n Rip Rap

In

P l.

U n d e r d r a in

C o n c

A p r o n

C o n c

A p r o n

S te e l

G r a te

C o n c

C o n c

C o n c

C o n c

Sign

M e ta l

G u a r d

R a il

Asphalt Sidewalk

Metal GuardRail

A s p h a lt S id e w a lk

Gravel Shoulder

Gravel Shoulder

C o n c

M e d ia n

Asphalt Shoulder

Asphalt Shoulder

Metal GuardRail

0.5 Asphalt Curb

0.5 Asphalt Curb

Metal GuardRail

A s p h a lt

J o h n

J

K in g m a n

R d

N. B. L.

Asphalt

Rte #286

Fairfax County Pkwy

S. B. L.

Asphalt

Rte #286

Fairfax County Pkwy

DB 10132 Pg 1369 Grading Esmt.

Construction and Ex. Temporary

DB 10132 Pg 1369 Drainage Esmt.

Ex. Storm

DB 10132 Pg 1369 Ex. Storm Drainage Esmt.

DB 10132 Pg 1369 and Grading Esmt.

Ex. Temporary Construction

RW Pin

RW Pin

Line

Begin L/A

Line

End L/A

Line

End L/A

Line

Begin L/A

UNITED STATES OF AMERICA

DB 1157 PG 163

TAX MAP# 115-2-01-0001

UNITED STATES OF AMERICA

DB 1157 PG 163

TAX MAP# 115-2-01-0001

F

TC

TC

TC

TC

TC

T

TC

N o

ID

T ra f.

S ig

T C

A

T r a f S ig

N o

ID

T r a f S ig

T r a f

C a b

N o

ID

E le c P o le

D

T r a f S ig

C O -X

H w

G u y

E le c.

P ol e

T C

T C

T C

Right Turn Lane Taper Right Turn Lane Storage Length

C

Legend:

C

F

Denotes Construction Limits in Cut

Denotes Construction Limits in Fill

Full-Depth Widening

K

IN

G M

A N

R O

A D

J O

H

J

FAIRFAX COUNTY PARKWAY WB (ROUTE 286)

(ROUTE 286)

FAIRFAX COUNTY PARKWAY EB

F

F

F

Existing CG-3

Alignment 286_BL of Pavement Existing Edge

Proposed Edge of Travelway

And R/W Line Existing Limited Access

And R/W Line Existing Limited Access

Remove Existing Guardrail Remove Existing Guardrail

F of Pavement Existing Edge

500ft

Storage Length Triple Left Turn

9' Long Posts GR-MGS1 Required, CG-7 Required

And R/W Line Limited Access Existing

9' Long Posts GR-MGS1 Required, 150ft200ft

Proposed CG-12B Ramp

Shared Use Path

CF

F F

S to r a g e

L e n g th

8ft f t

B

L T

L f t

L

S to r a g e

L e n g th f t

T r a n s it io n

Match Existing Pavement

KINGMAN_BL Sta. 200+00.00 286_BL Sta. 111+76.66 =

KINGMAN_BL

Alignment

Concrete

MGS GR within Limits of Project Existing Guardrail to be Replaced with within Limits of Project Replaced with MGS GR Existing Guardrail to be

Fairfax County Trail

Existing Utility Pole

Access and R/W Line Existing Limited

Fairfax County Trail

Remove Existing Inlet

Remove Existing Pipe

Remove Existing Endwall

Existing Inlet Remove

Pipe Remove Existing

Endwall Existing Remove

121.61' LT

Sta. 112+89.78 Mill and Overlay

46.14' RT

Sta. 111+61.97 Mill and Overlay

46.50' RT

Sta. 112+04.93 Mill and Overlay

130.99' LT

Sta. 111+05.88 Mill and Overlay

132.24' LT

Sta. 112+89.88 Mill and Overlay

Sta. 206+92.96 Transition Begin

(Expected 1.3-ft Fill) may be impacted Existing Signal Pole

Cross Slope to Existing Proposed SUP. Transition

Guardrail Existing Remove

1. Tree clearing required.

Notes:

Riprap

Storm Drainage Easement Proposed Permanent

Proposed R/W

R e q u ir e d

C

-6

Required

CG-6

Required

CG-6

Existing Signal Pole

CG-6 Required

CG-6 Required

CG-3 Required

Required

CG-7

9' Long Posts GR-MGS1 Required, GR-FOA-5 Required

Required

GR-FOA-5

2F(1)-2F(3)) (See Sheets Slab Approach Extend

Proposed Edge of Travelway and Regrade Existing Trail Demolish Existing Pavement

Existing Utility Pole may be Impacted

Demolish Existing Pavement Behind SUP and CG-12B

Proposed R/W

286_TRAIL_BL

Alignment

97.73' LT

Sta. 111+05.70 Mill and Overlay and Sta. 113+44.20 between Sta. 112+93.27

GR-MGS3, GR-MGS4

with Proposed 113+44.20 and Replace from Sta. 112+65.80 to Existing Guardrail Remove Impacted

Tie to Existing Guardrail

Required

GR-MGS4

Tie to Existing Guardrail

GR-MGS4 Required

Pavement Existing Match

Existing Signal Pole

Existing Signal Pole

Existing Controller Cabinet

Existing Signal Pole

Sawcut Required Full Depth

Sawcut Required Full Depth

Sawcut Required Full Depth

Sawcut Required Full Depth

Mill & Overlay (See Typical Sections)

Denotes Proposed R/W

CG-12B Ramp Proposed

CG-2 Required

121.82' LT

Sta. 112+37.13 Mill and Overlay

66.05' LT

Sta. 112+37.13 Mill and Overlay

Sawcut and Tie to Existing Trail

Sawcut Required Full Depth

Signal Pole Existing

Proposed Temporary Construction Easement

Construction Easement Proposed Temporary

Construction Easement Denotes Proposed Temporary

Proposed Temporary Construction Easement

Construction Easement Proposed Temporary

Construction Easement Proposed Temporary

Existing Inlet Remove

Pipe Existing Remove to Existing Curb and Gutter Sawcut and Tie Proposed CG-3

Sta. 31+20.00 to Existing Trail Sawcut and Tie

UD-4 Required

Required

UD-4

UD-4 Required

UD-4 Required

STA 202+25.00

MATCHLINE SHEET 6

S T

A

+7 .0

M

A T

C H

L

E E

T

S T

A

+0

.0

M A

T C

H L

E E

T

POT200+00.00

0 3

Curve 286_BL_9

PI = 113+07.64

T = 50.28'

L = 100.56'

R = 8,000.00'

112+57.36PC =

PT = 113+57.92

P T

+1 .9

0 11 1 11

P C

+5 .3

P T

+5 .9

Curve 286_BL_6

PI = 107+42.45

T = 73.51'

L = 147.01'

R = 4,220.00'

106+68.93PC =

PT = 108+15.95

E = Match Existing

V = 55 mph

E = Match Existing

V = 55 mph

15" 15"

15"

15" 15"

15" 15"

4-1

4-2

4-3

4-4 4-5

4-6

4-7

4-8

4-9

4-10

4-11

4-12

4-13

4-14

4-15

4-16 15"

J

J

CONSTRUCTION.

USED FOR ANY TYPE OF

UNAPPROVED AND ARE NOT TO BE

THESE PLANS ARE UNFINISHED AND

STA 107+00.00 TO STA 113+75.00

xchen Oval xchen Oval xchen Oval xchen Oval xchen Oval xchen Oval xchen Typewritten Text

KG-PC-03

xchen Typewritten Text

KG-PC-04

xchen Typewritten Text

KG-B-09

xchen Typewritten Text

KG-B-08

xchen Typewritten Text

KG-B-07

xchen Typewritten Text

KG-B-06

xchen Typewritten Text

KG-B-03

xchen Oval xchen Oval xchen Typewritten Text Soil Boring xchen

VA.

REVISED

STATE

dKNGWLK05.dgn

Plotted By: buchanantm4:11:04 PM

1/25/2021

PROJECT SHEET NO.

DESIGN FEATURES RELATING TO CONSTRUCTION

OR TO REGULATION AND CONTROL OF TRAFFIC

MAY BE SUBJECT TO CHANGE AS DEEMED

NECESSARY BY THE GOVERNMENT

SURVEYED BY, DATE

PROJECT MANAGER

SCALE

25' 50'

ROADWAY ENGINEER

Herndon, Virginia

WSP USA, INC

SUBSURFACE UTILITY BY, DATE

TIMOTHY J. RAMEY, PE (WSP USA, INC.)

EASTERN FEDERAL LANDS HIGHWAY DIVISON

WLKR GTS

VA ST FB_KNGMN /

WLKR GTS

VA ST FB_KNGMN /

RICE ASSOCIATES, (703) 968-3200, OCTOBER 2019, SUPPLEMENTED MAY 2020

RICE ASSOCIATES,…