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SOILS AND FOUNDATIONS
REPORT NO. 08-14
PROJECT NC ERFO FSR 2013-1(2)
LANDSLIDES REPAIR
TUNI GAP ROAD (NFSR # 440)
CLAY AND MACON COUNTIES, NORTH CAROLINA
U.S. Department of Transportation
Federal Highway Administration
Eastern Federal Lands Highway Division
21400 Ridgetop Circle
Sterling, VA 20166
May, 2015
TABLE OF CONTENTS
REPORT SECTION ............................................................................................... PAGE
Introduction General
Project Location
Background
Subsurface Exploration Program Drilling and Sampling
Data Summary
Laboratory Testing
Geophysical Survey
Subsurface Conditions Regional Geology
Stratification
Groundwater
Seismic Refraction Survey
Design Analyses and Recommendations Design Alternatives
Design Analyses
Construction Considerations General
Excavations
Backfill Material
Disclaimer/Limitations Clause
APPENDICES
A Figures
B Borings Location Maps
C Subsurface Profiles
D Boring Logs
E Laboratory Test Results
F Seismic Refraction Results
G Design Analyses
H Photographs
Note: Design changes subsequent to publication of this report and prior to the project’s advertisement will be documented by a memo inserted after the title page.
DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
SOILS AND FOUNDATIONS
REPORT NO. 08-14
PROJECT NC ERFO FSR 2013-1(2)
TUNI GAP ROAD (NFSR # 440)
CLAY AND MACON COUNTIES, NORTH CAROLINA
INTRODUCTION
General
This report presents the results of the subsurface exploration, laboratory testing, and geotechnical analysis and provides our evaluations and recommendations for the repair of eighteen (18) landslides along Tuni Gap Road, National Forest Service Road (NFSR)
No. 440, as reported in the Damage Survey Reports (DSR)
Project Location
The project includes 18 landslide sites along Tuni Gap Road (NFSR#440) within the
Nantahala National Forest spanning Clay and Macon counties in southwestern North
Carolina. Table 1 provides a list of the landslide sites.
Table 1 – Summary of Landslide Sites along Tuni Gap Road
Site No. Mile Post County
1 0.158 Clay
2 0.370 Clay
3 0.788 Clay
4 1.243 Clay
5 1.478 Clay
6 1.676 Clay
7 1.977 Clay
8 2.358 Clay
9 2.437 Clay
10 2.49 Clay
11 2.541 Clay
12 3.509 Clay
13 3.57 Clay
1 Damage Survey Report, Disaster No. NC2013-1-FS, Federal Highway Administration, Federal Lands
Highway. (July 2013)
PROJECT NC ERFO FSR-2013-1(1)
NORTH CAROLINA ERFO NC2013-1-FS
CHEROKEE AND GRAHAM COUNTY, NORTH CAROLINA
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Table 1 – Summary of Landslide Sites along Tuni Gap Road
Site No. Mile Post County
14 4.196 Clay
15 4.383 Clay
16 4.837 Clay
17 5.247 Macon
18 5.404 Macon
A site location and vicinity map is presented in Figure 1, Appendix A.
Background
Damage Survey Reports dated July 2013 indicated that landslide and embankment failures were observed along NSRF #440 following heavy rain events in early 2013.
EFLHD personnel performed a site reconnaissance in October 2013 and the findings are described in the Field Trip Report dated November 19, 2013.
SUBSURFACE EXPLORATION PROGRAM
Drilling and Sampling
A subsurface exploration program consisting of soil borings and geophysical (seismic refraction) testing was conducted to characterize subsurface conditions. Drilling was performed by the EFLHD subsurface exploration team between April 12 and May 1, 2014. The program consisted of drilling thirty six (36) soil borings to depths ranging from approximately 1 to 52 feet below existing site grades. Table 2 provides a summary of the boring locations and depths.
Table 2 – Boring locations, depths, and ground surface elevations
Boring No. Location Northing Easting
Ground Surface
EL
(feet)
Boring
Depth (feet)
B-02 Site 1 - MP 0.158 523846.50 593269.98 2200.5 16.2
B-02A¶ Site 1 - MP 0.158 523854.82 593248.86 2198.3 20.5
B-04 Site 2 - MP 0.370 524530.46 594031.30 2273.1 2.7
B-04A¶ Site 2 - MP 0.370 524487.77 594047.04 2273.7 5.5
B-06 Site 2 - MP 0.370 524783.28 594010.00 2275.1 32.7
2 Damage Survey Report, Disaster No. NC2013-1-FS, Federal Highway Administration, Federal Lands
Highway. (July 2013) 3 Field Trip Report, NC ERFO FSR 2013-1(2), Federal Highway Administration, Eastern Federal Lands
Highway Division. (Nov 2013)
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Table 2 – Boring locations, depths, and ground surface elevations
Boring No. Location Northing Easting
Ground Surface
EL
(feet)
Boring
Depth (feet)
B-08 Site 3 - MP 0.788 526155.95 594836.22 2306.0 38.5
B-10 Site 4 - MP 1.243 528186.06 595688.03 2508.6 37.0
B-12 Site 5 - MP 1.478 529272.54 596047.39 2529.4 32.0
B-14 Site 6 - MP 1.676 530179.83 596022.28 2537.5 37.0
B-15 Site 7 - MP 1.977 531508.28 596332.18 2583.3 24.5
B-16 Site 7 - MP 1.977 531615.46 596366.13 2587.0 3.5
B-17 Site 8 - MP 2.358 532992.89 597209.96 2645.5 15.2
B-18 Site 8 - MP 2.358 533063.86 597204.93 2647.5 9.1
B-19 Site 9 - MP 2.437 533367.84 597206.48 2656.9 14.3
B-20 Site 9 - MP 2.437 533438.11 597222.43 2659.5 6.7
B-21 Site 10 - MP 2.49 533645.07 597200.54 2665.3 14.6
B-22 Site 10 - MP 2.49 533682.18 597202.75 2665.9 30.0
B-23 Site 11 - MP 2.541 533846.54 597314.57 2672.2 39.0
B-24 Site 12 - MP 3.509 538668.35 597716.39 2968.5 17.0
B-24A Site 12 - MP 3.509 538628.78 597704.66 2967.3 17.0
B-25 Site 12 - MP 3.509 538763.20 597713.51 2970.8 24.7
B-25A¶ Site 12 - MP 3.509 538829.99 597702.18 2973.4 26.0
B-26 Site 13 - MP 3.57 538948.37 597605.40 2977.6 12.0
B-26A¶ Site 13 - MP 3.57 538975.92 597575.04 2979.3 26.0
B-27 Site 13 - MP 3.57 539013.06 597545.71 2981.3 38.2
B-28 Site 13 - MP 3.57 539152.69 597459.78 2986.8 10.7
B-29 Site 14 - MP 4.196 541437.11 596465.28 3142.0 1.0
B-30 Site 14 - MP 4.196 541457.69 596535.68 3151.1 15.0
B-31 Site 15 - MP 4.383 542041.22 597002.74 3226.5 50.2
B-32 Site 15 - MP 4.383 542090.87 596981.20 3231.6 52.0
B-33 Site 16 - MP 4.837 544000.97 597099.53 3496.7 36.3
B-34 Site 16 - MP 4.837 544045.26 597140.65 3497.7 27.2
B-35 Site 17 - MP 5.247 545602.96 596807.57 3435.6 52.0
B-35A Site 17 - MP 5.247 545660.59 596845.52 3441.0 39.0
B-36 Site 18 - MP 5.404 545980.16 596533.45 3391.3 24.0
B-37 Site 18 - MP 5.404 546095.71 596483.21 3383.2 43.4
*Horizontal coordinates referenced to US State Plane Zone 3200 NC (NAD 1983)
**Elevations referenced to North American Vertical Datum of 1988 (NAVD 1988) ¶Borings advanced for full depth without sampling until auger refusal was reached
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Borings were drilled using a CME 750 drill rig mounted on a rubber tired all-terrain vehicle (ATV). Boreholes were advanced using 3-¾-inch (inside diameter) hollow stem augers (HSA) in soil and highly weathered rock. Borings were terminated upon reaching auger refusal or after reaching the planned boring depth. Boring locations were laid out by EFLHD personnel in the field by referencing topographic features, measuring distances from existing surface features, and estimating right-angles. Upon completion, boring locations were surveyed by the EFLDH Survey Team to obtain ground surface elevations and horizontal coordinates at each boring location.
Soil samples were obtained using a standard split-barrel (split-spoon) sampler driven during Standard Penetration Tests (SPT) in general accordance with ASTM D 1586, Standard Method of Penetration Test and Split Barrel Sampling of Soils. SPT was performed by driving the split-spoon sampler a distance of 24 inches into the undisturbed soil under the impact of a 140-pound automatic hammer free falling 30 inches. SPT was generally performed at 2.5-foot interval in the upper 20 feet and at 5-foot intervals thereafter. The number of hammer blows required to advance the split-spoon sampler the middle foot of the 24-inch sample interval is designated as the
“Standard Penetration Resistance” or N value. The number of blows required to advance the sampler through each 6-inch interval was recorded on field boring logs.
SPT refusal is defined by achieving 50 blows per 1-inch (or less) of the split-spoon sampler.
Representative portions of the split-spoon samples were preserved in glass jars. The samples were visually classified and logged in the field by the crew team leader.
Samples were then delivered to the EFLHD Materials Testing facility in Sevierville, Tennessee for testing and storage. Details on sampling and sample descriptions are provided in the boring logs included in Appendix D of this report. Boreholes were backfilled with auger cuttings upon completion.
Data Summary
Data collected from the exploratory borings was recorded on the driller’s logs. These data sheets and logs indicate the boring methods, samples attempted and recovered, indications of the presence of various materials such as gravel, pebbles, organic matter, and observations of groundwater. The logs also contain interpretations of the subsurface conditions based on the performance of the equipment and cuttings brought to the surface by the drilling tools. Therefore, the field data represent both factual and interpretative information.
The boring logs provided in Appendix D represent a compilation of field and laboratory data and description of the soil samples by a geotechnical engineer. These records occasionally do not include all data recorded on driller’s logs and field data sheets, but do include all information considered relevant to the design and preparation of this report.
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Groundwater levels, when encountered, were measured in the boreholes at the times and under the conditions stated in the boring logs. Fluctuations in groundwater level due to seasonal variations, rainfall, temperature, and other factors not evident at the time measurements were made should be expected.
Laboratory Testing
Laboratory testing was performed on representative soil samples recovered during the subsurface exploration to aid in classification and evaluation of engineering parameters of the subsurface materials. The following tests were performed on selected samples.
Particle size analysis (AASHTO T-11 and T-27)
Moisture content (AASHTO T-265)
Liquid Limit (AASHTO T-89)
Plastic Limit (AASHTO T-90)
Organic Content (AASHTO T-267)
A summary of the laboratory test results is presented in Tables 3. Laboratory test results are provided in Appendix E.
Table 3 – Summary of Soil Laboratory Test Results
Boring
No.
Sample
No.
Sample
Depth
(feet)
Gravel
Sand
Fines
Moisture
Content
B-02 J-2 3-5 36.3 44.3 19.4 12.9
B-02 J-4,J-5 8-10 27.2 48.8 24 5.1
B-06 J-3 5-7 6 65.2 28.8 18.3
B-06 J-5 8-10 - - - 14.4
B-06 J-6 15-17 0 56.4 43.6 14.8
B-08 J-4 8-10 - - - 20.7
B-08 J-6 15-17 0 58.8 41.2 31.8
B-08 J-10 35-37 1.6 60.3 38.1 22.0
B-10 J-4 8-10 26 59 15 9.0
B-10 J-8 25-27 4.2 69.8 26 11.5
B-12 J-3 5-7 0 64.4 35.6 15.3
B-12 J-7 20-22 16.6 54.9 28.5 18.6
B-14 J-4 8-10 36.9 41.8 21.3 14.8
B-14 J-6 15-17 2.2 50 47.8 18.2
B-14 J-9 30-35 - - - 17.5
B-15 J-2 3-5 10.6 51 38.4 17.9
B-15 J-5 10-12 21.7 55.3 23 12.4
B-15 J-6 15-17 - - - 18.4
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Table 3 – Summary of Soil Laboratory Test Results
Boring
No.
Sample
No.
Sample
Depth
(feet)
Gravel
Sand
Fines
Moisture
Content
B-17 J-2 3-5 0.4 77.7 21.9 12.9
B-17 J-5 10-12 3.1 71.8 25.1 16.7
B-19 J-3 5-7 1.8 77.4 20.8 18.3
B-22 J-4 8-10 5.9 66.3 27.8 21.3
B-22 J-7 20-22 6.5 71.2 22.3 19.6
B-23 J-3 5-7 19.3 60.2 20.5 13.0
B-23 J-7 20-22 4 57.8 38.2 22.6
B-24 J-5 10-12 3.3 59.5 37.2 11.7
B-24A J-3 5-7 3.7 51.6 44.7 12.6
B-25 J-5 10-12 10.8 62.4 26.8 14.4
B-26 J-5 10-12 23.8 57.6 18.6 9.4
B-27 J-5 10-12 1.1 74 24.9 23.6
B-27 J-7 20-22 0 74.3 25.7 15.5
B-28 J-4 8-10 34.6 51.1 14.3 5.4
B-30 J-3 5-7 11.4 57.8 30.8 18.4
B-31 J-8 25-27 3 49.1 47.9 34.5
B-32 J-3 5-7 3.5 41.9 54.6 30.6
B-32 J-10 35-37 31.8 44.6 23.6 29.0
B-33 J-8 25-27 0.8 78.7 20.5 15.8
B-33 J-9 30-32 26.9 52.9 20.2 10.6
B-34 J-4 8-10 0 77.9 22 -
B-35 J-5 10-12 22.2 45.7 32.1 -
B-35 J-8 24-26 0 78.6 21.4 109.3
B-35A J-8 25-27 21.1 50.9 28 17.4
B-36 J-3 5-7 10.2 60.4 29.4 14.4
B-36 J-6 13-15 0.4 62.6 37 16.2
B-37 J-7 20-22 20.9 50.1 29 -
Note: All samples tested for liquid and plastic limits were found to be non-plastic
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Geophysical Survey
EFLHD performed a geophysical refraction survey on February 20, 2014 to further assess the subsurface conditions at sites 2, 13, and 18. The seismic refraction survey was performed in general accordance with ASTM D 5777, Standard Guide for Using the Seismic Refraction Method for Subsurface Investigations using a line of geophones and a GEODE-24 Multi-channel Seismograph device. Geophones were laid on the ground along the existing roadway, spaced at 10-foot intervals with a total length of
650 feet, 230 feet, and 230 feet, for sites 2, 13, and 18, respectively, described in this report as the spread lines.
Seismic energy was generated using a 20-pound sledge hammer swung manually against a striker plate on the ground. The striker plate improves the coupling of energy from the hammer to the ground. Each shot set included three hammer blows to enhance the signals read by the seismograph. Seven (7) shot sets were performed for each spread line. Shot locations included one shot 10 feet beyond each end of the spread line, known as off-end shots. Shot were also taken at the limits of the spread line near the first and last geophone. Interior shots were also taken at quarter points and at the center of the spread line. The locations of the spread lines were surveyed to determine horizontal and vertical coordinates. The location of the geophysical survey lines are referenced on the boring location maps provided in Appendix B. The processed the geophysical data was processed using SeisImager 2-dimensional seismic refraction data analysis software by Geometrics, Inc. The seismic refraction survey results are included in Appendix F.
SUBSURFACE CONDITIONS
Regional Geology
According to the “Geologic Map of North Carolina,” North Carolina Geologic Survey
(1985), all sites lie within the Dean Formation (Zd), which consists of mica schist. The rock is described as sericite schist with cross-biotite, staurolite, and garnet phophyroblasts minerals and interbedded with metagraywacke and quartz-pebble metaconglomerate.
A geologic map of the project area is provided as Figure 2 in Appendix A of this report.
Stratification
A brief description of the subsurface conditions encountered during our field work is listed below. Generalized subsurface profiles are presented in Appendix D of this report. Note that stratification lines designating the interfaces between layers on the boring logs and the subsurface profiles represent approximate boundaries while the
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
transition between materials may be gradual. It should be noted that one or more of the units may be absent at specific locations.
The subsurface profile can be classified into the following strata based on descriptions on the boring logs, where classifications of the samples are recorded.
Fill
Fill was encountered in all of the borings performed except at site 10 where the fill only consisted of the roadway aggregate. Generally, fill material consisted of very loose to medium dense, brown and gray, silty sand with gravel, and poorly graded gravel with silt, and silty gravel. Cobbles and boulders were also encountered in the fill at Site 4.
SPT N-values recorded ranged from 1 to 24 blows per foot (bpf), with an average of approximately 8 bpf. This layer thickness varied from less than approximately 1 to 30 feet. Based on the variations in SPT N values noted in the borings, it is our judgment that the fill was placed in an uncontrolled manner, as the relative densities of these materials vary markedly with depth.
Residuum
Underlying the Fill stratum, residual soil was encountered in all sites except at sites 1 and 14 where Fill was underlain by Highly Weathered Rock. This layer was formed as a result of in-situ weathering of the parent rock material and has no relic structure. This stratum generally consists of light to dark brown and gray silty sand with varying amounts of gravel. SPT N values generally ranged from 6 to 41 bpf with an average blow count of 19 bpf. When present, this layer ranged in thickness from approximately
9 feet to more than 40 feet.
Highly Weathered Rock
Underlying the Fill and the Residual Soil stratums, weathered rock was encountered.
The weathering profile varied from decomposed and completely weathered at the top of the layer to less weathered with increasing depth. This stratum consists of reddish brown silty sand and sandy silt with gravel sized rock fragments and was medium dense to very dense. The layer exhibited relic rock structure with varying amounts of mica.
Bedrock
Underlying the Highly Weathered Rock stratum, bed rock was encountered at depths ranging from approximately 6 feet to more than 50 feet below ground surface as determined when auger refusal was reached. Rock coring was not performed as part of this study; however, based on geologic mapping, rock is expected to consist of serecite schist interbedded with metagraywacke and quartz-pebble metaconglomerate.
Groundwater
Groundwater was not encountered during our drilling operations; however, several samples were found to be “wet” upon retrieval, indicating possible perched
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
groundwater conditions. Note that changes in groundwater levels should be expected due to seasonal variations, precipitation, evaporation, and surface water runoff.
Seismic Refraction Survey
The seismic refraction survey results were used to evaluate the soil/weathered rock interface based on the compression wave (p-wave) velocity. Our interpretation of the correlation between soil/rock and p-wave velocities is presented in Table 4.
Table 4 - Seismic refraction survey results
Soil Type/Density
P -wave Velocity (ft/s)
Site 1
Fill and Residual Soil <2,000
Highly Weathered Rock 2,000-5,000
Rock >5,000
In general, the refraction survey results were in agreement with the data obtained from the soil borings with the exception of B-37, which indicated that rock may be up to 20 feet deeper than what was determined from the geophysical survey results. Results from the refraction survey are provided in Appendix F of this report.
DESIGN ANALYSES AND RECOMMENDATIONS
Design Alternatives
Landslides occur as a result of unbalanced pressures along sloping ground. The addition of water worsens the conditions along a slope by increasing the driving forces and in some cases reducing the strength of the in-situ materials. To mitigate slope stability problems, two general approaches can be used. One approach is to reduce the driving forces by reducing weight, flattening the slope, adjusting roadway grading, or by installing surface and subsurface drainage systems. The second approach is to increase the resisting forces by buttressing, adding counterweight fills, adding a retaining structure, or by reinforcing the embankment fill to increase its strength.
Two alternatives were considered feasible and effective for the landslides repairs for this project based on subsurface conditions, constructability, cost, and our experience with similar projects. The alternatives are briefly discussed below:
Alternative 1 –Reinforced Soil Slope (RSS)
This alternative consists of reconstructing the hillside fill embankment with geosynthetic reinforced soil, supported on firm, natural soils. This concept effectively increases the resisting forces and moments due to the increased strength of the geosynthetic reinforced fill material. This alternative may require installation of
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
temporary excavation support for excavations that require slopes that exceed the strength of the in-situ material. The reinforced soil slope can be constructed with a facing that nearly matches the slope of the existing hillside fill slope, which is generally at a slope ratio of 1V:1H or steeper.
Alternative 2 –Expanded Polystyrene (EPS) - Geofoam
This alternative consists of reconstructing the hillside fill embankment along the landslide and backfilling with expanded polystyrene, also known as geofoam. EPS is manufactured by an internal expansion process that results in a lightweight material weighing less than 4 pounds per cubic foot. The use of EPS for road construction is an established technology that has been used for over 30 years worldwide. The lightweight and internal shear strength of the EPS blocks effectively reduce or eliminate the driving forces along the hillside fill thereby stabilizing the road embankment. While there is a wide range of lightweight materials that can be used for this application, for example lightweight aggregate, wood fibers and shredded tires, EPS provides unique advantages because of its rapid placement during construction and consistency of material properties.
A comparison on the two alternatives previously described is provided in Table 5.
Table 5 – Landslide Repair Alternative Comparison
No. System Advantages Disadvantages
1 Geosynthetic
Reinforced
Slope
Flexible system that can accommodate varying subsurface conditions
Cost effective
Simple construction
Requires high quality imported backfill material
Compaction is required to achieve design strength
May require shoring for temporary cut slopes
Weight of backfill adds to driving forces
2 Geofoam
(Expanded
Polystyrene)
Low unit weight
Easy handling of material
Rapid construction
No compaction required
Can be easily trimmed and cut in the field to fit terrain
Can be placed in adverse weather
Reduces settlements
Reduces lateral stresses
Cost
Subject to degradation when exposed to termites, UV radiation, and petroleum
Requires drainage system to prevent hydrostatic uplift forces
Requires soil cover to protect against environmental factors
From a constructability perspective and because of its rapid construction, Alternative 2 is most favorable. However, based on preliminary cost estimates, Alternative 2 is expected to exceed the available project funds making it cost prohibitive. Therefore, Alternative 1 was selected.
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
Design Analyses
Design of the geosynthetic reinforced slopes was conducted using limit equilibrium design methodology, in general accordance with the design concepts and procedures presented in FHWA Publication FHWA-GEC 011, “Design and Construction of
Mechanically Stabilized Earth Walls and Reinforced Soil Slopes,” (2010). Stability analyses for internal, external, and compound failure modes were evaluated to determine the required reinforcement embedment lengths.
A summary of soil and rock strength parameters assumed in the stability analyses are presented in Table 6.
Table 6 – Summary of Material Properties
Material
Type
Unit Weight, γ
(pcf)
Drained Cohesion, c’ (psf)
Drained Angle of
Internal Friction, Φ’ (deg)
New Fill Soil* 125 0 34
Existing Soil Fill** 120 0-25 28-34
Residuum 130 0-250 30-33
Highly Weathered
Rock¶ 135 400-500 34-35
Bedrock¶ 140 2,000 36
* Material assumed to be select granular backfill meeting the requirements of FP-14
Section 704.08 ** Strength of in place soil was approximated based on back-analysis of pre-failed slope ¶Rock properties determined based data developed by Hoek and Bray (1981) and
Kulhawy (1975)
A uniformly distributed surcharge load of 250 psf was applied along the top of the slope to account for traffic live loading.
Stability analyses were performed using the computer programs Slide v. 6.0 by
Rocscience, Inc. Computer output files are included in Appendix G. The output files provide the soil input properties, wall sections geometry analyzed, reinforcement spacing, type, strength and interaction parameters, the calculated safety factor for the stability criteria presented above, and plots of the calculated critical failure plane.
To satisfy the design criteria, the following general requirements are recommended for repairing the landslides using geosynthetic reinforced soil.
Geosynthetic reinforcement type – biaxial or triaxial geogrid
Minimum allowable long-term design strength (Tall) – 1,000 pounds/foot
Minimum ultimate strength (Tult) – 4,000 pounds/foot
Maximum vertical spacing of geosynthetic – 1.5 feet
Site specific requirements for the geosynthetic reinforcement are provided in Table 7.
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STERLING, VIRGINIA
Table 7 – Geosynthetic Reinforced Slope Requirements
Site No.
Total Height (H)*
[feet]
Minimum Height of
Reinforced Soil Zone
[feet]
Min. Required
Reinforcement Length
[feet]
Minimum No. of
Geogrid Layers
1 9 7.5 18 6
2 9 7.5 19 6
3 13.5 12 20 9
4 16.5 15 19 11
5 6 4.5 18 4
6 16.5 15 18 11
7 12 10.5 16 8
8 9 7.5 19 6
9 6 4.5 15 4
10 18 16.5 20 12
11 16.5 15 17 11
12 7.5 6 16 5
13 13.5 12 20 9
14 10.5 9 17 7
15 15 13.5 18 10
16 16.5 15 21 11
17† 15 13.5 20 10
18 16.5 15 20 11
*Total Height (H) is measured from 1.5 feet above the top layer of geogrid †For Site 17 use of lightweight aggregate is required for backfill within the reinforced soil zone to satisfy global stability requirements
For facing slopes at or steeper than 1V:1H, permanent facing support is recommended.
A bent-up, L-shaped, welded-wire-mesh form with geotextile wrapping for erosion control and wrapping of the primary geogrid reinforcing is recommended for permanent facing support.
Lightweight aggregate backfill is recommended for Site 17 within the geosynthetic reinforced zone to satisfy global stability requirements. Lightweight aggregate made of
Expanded Shale, Clay, & Slate (ESCS) is recommended with a gradation equivalent to
AASHTO M 43 size #57. The following material aggregate physical properties are recommended.
Soundness loss – maximum 40% (ASTM C 131)
Abrasion loss – maximum 100 ppm (AASHTO T 291)
Loose bulk density – maximum 55 lbs per cubic foot (ASTM C 29)
At all other sites, normal weight, free-draining aggregate backfill with less than 5 percent fines meeting the gradation requirements of AASHTO M 43 size #57 is
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
recommended. Aggregate should be free of organic matter, lumps or balls of clay, and other deleterious material.
CONSTRUCTION CONSIDERATIONS
General
Construction shall be performed following the Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects (FP-14) and the Special Contract
Requirements (SCR).
Unless free-draining backfill material is used for backfill within the reinforced zone, drains are recommended behind the reinforced zone to prevent hydrostatic pressures. If free draining backfill is used within the reinforced zone, underdrains should be used beneath the backfill to drain water that may infiltrate into the backfill zone. Surface runoff should also be diverted at the top of the slope to prevent it from flowing over the face. Surface runoff that is collected above the reinforced slope should be channeled or piped outside limits of slope repair.
Subgrade below the reinforced soil zone should be prepared in accordance with
Subsection 208.08 of the FP-14 Specifications.
Excavations
All excavations are to be performed in accordance with applicable federal, state, local, and OSHA requirements and in accordance with Section 204 of the FP-14
Specifications. Excavation in fill and/or natural material should be achievable using conventional earthmoving equipment in proper working condition.
Excavation slopes will be required to remove the existing hillside fill embankments and replace with geosynthetic reinforced soil to the recommended depth and width. Due to the variability of subsurface profile within the landslide areas, there is a possibility of localized slope instability within temporary cut slopes. The contractor should provide temporary excavation support as needed during construction or as directed by the
Contracting Officer to provide safe excavations. Soil nails or rock dowels may be used to reinforce any localized slope instabilities.
Backfill Material
Backfill should be placed and compacted in accordance with Section 204 of the FP-14
Specifications. Aggregates should conform to requirements in Section 703 of the FP-14
Specifications.
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
DISCLAIMER/LIMITATIONS CLAUSE
The subsurface explorations and test described in this report have been conducted in accordance with standard practices and procedures (except as specifically noted). The results of these exploration and test represent conditions at the specific locations and dates indicated. Subsurface conditions between these locations may vary. The Geotechnical
Design Analyses and Recommendations Sections of this report include interpretations and recommendations developed by the Government in the process of preparing the design.
These interpretations are not intended as a substitute for the personal investigation, independent interpretation, and judgment of the Contractor.
Prepared by:
Francis A. Abreu, P.E.
Geotechnical Engineer
Reviewed by:
Mounir Abouzakhm, P.E.
Division Geotechnical Engineer
APPENDIX A
Figures
NC ERFO FSR 2013-1(2)
Zd
Zhha
Znt
ZYbn
Zwe
Zch
Zch
Zb
ZYba
Zwe
ZYba
Site 13 - MP 3.57
Site 10 - MP 2.49Site 9 - MP 2.437
Site 7 - MP 1.977
Site 6 - MP 1.676 Site 5 - MP 1.478
Site 4 - MP 1.243
Site 3 - MP 0.788
Site 2 - MP 0.370 Site 1 - MP 0.158
Site 18 - MP 5.404 Site 17 - MP 5.247
Site 16 - MP 4.837
Site 15 - MP 4.383 Site 14 - MP 4.196
Site 12 - MP 3.509
Site 11 - MP 2.541
Sources: Esri, DeLorme, HERE, USGS, Intermap, increment P Corp., NRCAN, Esri Japan, METI, Esri China (Hong Kong), Esri (Thailand), TomTom
Legend
Metasedimentary rock (2)
Slate (2)
Mica schist (2)
Biotite gneiss (1)
Amphibolite (2)
FIGURE 2
GEOLOGIC MAP
US DEPARTMENT OF TRANSPORTATION
FEDERAL LANDS HIGHWAY DIVISION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
STATE PROJECT
NC NC ERFO FSR
2013-1(2)
SHEET
NO.
0 1 20.5 Miles
Zd - Dean Formation Sericite schist with cross-biotite, staurolite, and garnet porphyroblasts; interbedded metagraywacke and quartz-pebble metaconglomerate.
Zhha - Metasandstone, Metagraywacke, Metasiltstone, and Mica Schist - beds and lenses of calc-silicate rock locally abundant; garnet, staurolite, and cross-biotite porphyroblasts common in fine-grained layers. Includes Hughes Gap and Hothouse formations in southern area; Horse Branch Member of Ammons Formation and Grassy Branch Formation in northern area.
USGS Geologic Data Source: The North Carolina Dept. of Environment, Health, and Natural Resources, Division of Land Resources, NC Geological Survey, in cooperation with the NC Center for Geographic Information and Analysis, 1998, Geology - North Carolina (1:250,000), coverage data file geol250.
APPENDIX B
Boring Location Map
APPENDIX C
Subsurface Profile
2,176
2,178
2,180
2,182
2,184
2,186
2,188
2,190
2,192
2,194
2,196
2,198
2,200
2,202
2,176
2,178
2,180
2,182
2,184
2,186
2,188
2,190
2,192
2,194
2,196
2,198
2,200
2,202
1.3
1.4
1.0
0.4
0.6
0.5
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL DECOMPOSED
ROCK SMGroundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
16.2
Depth (ft) B-02
N Rec.
0.6
20.5
Depth (ft) B-02A
B-02B-02A francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY WEATHERED ROCK
francis.abreu Polygonal Line francis.abreu Text Box
ROCK
francis.abreu Text Box francis.abreu Text Box
NC 1
francis.abreu Text Box
SITE 1
2,240
2,245
2,250
2,255
2,260
2,265
2,270
2,275
2,280
2,240
2,245
2,250
2,255
2,260
2,265
2,270
2,275
2,280
50 0.8
1.7
1.6
1.5
1.7
1.5
1.8
0.9
0.9
0.4
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL DECOMPOSED
ROCK SM FILLGroundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
2.7
Depth (ft) B-04
N Rec.0.5
5.5
Depth (ft) B-04A 0.5
3.5
32.7
Depth (ft) B-06
N Rec.
B-04 B-04A B-06 francis.abreu Polygonal Line francis.abreu Text Box francis.abreu Text Box francis.abreu Text Box francis.abreu Text Box
FILL
francis.abreu Text Box
RESIDUUM
francis.abreu Text Box
HIGHLY WEATHERED ROCK
francis.abreu Text Box
ROCK
francis.abreu Polygonal Line francis.abreu Polygonal Line francis.abreu Polygonal Line francis.abreu Text Box
NC 2
francis.abreu
SITE 2
2,265
2,270
2,275
2,280
2,285
2,290
2,295
2,300
2,305
2,310
2,265
2,270
2,275
2,280
2,285
2,290
2,295
2,300
2,305
2,310
1.3
1.5
1.4
1.6
1.6
1.7
1.8
1.8
1.8
1.9
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
38.5
Depth (ft) B-08
N Rec.
B-08 francis.abreu Line francis.abreu Text Box
FILL
francis.abreu Line francis.abreu Text Box
RESIDUUM
francis.abreu Line francis.abreu Text Box
HIGHLY WEATHERED ROCK
francis.abreu Line francis.abreu Text Box
ROCK
francis.abreu Text Box
NC 3
francis.abreu
SITE 3
2,470
2,475
2,480
2,485
2,490
2,495
2,500
2,505
2,510
2,470
2,475
2,480
2,485
2,490
2,495
2,500
2,505
2,510
0.7
0.2
1.2
1.6
0.9
1.4
1.6
1.7
1.6
0.6
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
Depth (ft) B-10
N Rec.
B-10 francis.abreu Line francis.abreu Text Box
FILL
francis.abreu Line francis.abreu Text Box
RESIDUUM
francis.abreu Line francis.abreu Text Box
HIGHLY WEATEHRED ROCK
francis.abreu Text Box
NC 4
francis.abreu
SITE 4
2,495
2,500
2,505
2,510
2,515
2,520
2,525
2,530
2,495
2,500
2,505
2,510
2,515
2,520
2,525
2,530
1.6
1.6
1.7
1.9
1.9
1.8
1.7
1.8
1.9
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
1.5
Depth (ft) B-12
N Rec.
B-12 francis.abreu Line francis.abreu Text Box
FILL
francis.abreu Line francis.abreu Text Box
RESIDUUM
francis.abreu Line francis.abreu Text Box
HIGHLY WEATEHRED ROCK
francis.abreu Text Box
NC 5
francis.abreu
SITE 5
2,500
2,505
2,510
2,515
2,520
2,525
2,530
2,535
2,540
2,500
2,505
2,510
2,515
2,520
2,525
2,530
2,535
2,540
1.9
1.1
1.4
0.9
1.3
1.7
1.1
1.5
1.7
0.4
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
Depth (ft) B-14
N Rec.
B-14 francis.abreu Line francis.abreu Text Box
FILL
francis.abreu Line francis.abreu Text Box
RESIDUUM
francis.abreu Line francis.abreu Text Box
HIGHLY WEATEHRED ROCK
francis.abreu Text Box
NC 6
francis.abreu
SITE 6
2,558
2,560
2,562
2,564
2,566
2,568
2,570
2,572
2,574
2,576
2,578
2,580
2,582
2,584
2,586
2,588
2,558
2,560
2,562
2,564
2,566
2,568
2,570
2,572
2,574
2,576
2,578
2,580
2,582
2,584
2,586
2,588
1.8
1.4
1.5
1.3
1.3
1.7
1.9
1.4
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
21.5
24.5
Depth (ft) B-15
N Rec.
0.5
2.5
3.5
Depth (ft) B-16
N Rec.
B-15 B-16 francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY
WEATEHRED
ROCK
francis.abreu Polygonal Line francis.abreu Text Box
ROCK
francis.abreu Text Box francis.abreu Text Box francis.abreu Text Box
NC 7
francis.abreu
SITE 7
2,630
2,632
2,634
2,636
2,638
2,640
2,642
2,644
2,646
2,648
2,630
2,632
2,634
2,636
2,638
2,640
2,642
2,644
2,646
2,648
0.6
1.8
1.5
1.4
1.4
0.2
1.8
1.5
0.8
0.2
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
15.2
Depth (ft) B-17
N Rec.
0.5
9.1
Depth (ft) B-18
N Rec.
B-17 B-18 francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY
WEATEHRED
ROCK
francis.abreu Polygonal Line francis.abreu Text Box
ROCK
francis.abreu Text Box
NC 8
francis.abreu
SITE 8
2,642
2,644
2,646
2,648
2,650
2,652
2,654
2,656
2,658
2,660
2,642
2,644
2,646
2,648
2,650
2,652
2,654
2,656
2,658
2,660
1.4
2.0
1.8
1.6
1.0
0.8
0.2
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
14.3
Depth (ft) B-19
N Rec.
0.5
6.7
Depth (ft) B-20
N Rec.
B-19 B-20 francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY
WEATEHRED
ROCK
francis.abreu Polygonal Line francis.abreu Text Box
ROCK
francis.abreu Text Box
NC 9
francis.abreu
SITE 9
2,635
2,640
2,645
2,650
2,655
2,660
2,665
2,670
2,635
2,640
2,645
2,650
2,655
2,660
2,665
2,670
1.8
1.6
1.8
2.0
1.6
0.9
1.1
1.2
0.7
1.9
0.3
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL SM DECOMPOSED
ROCK FILLGroundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
14.5
Depth (ft) B-21
N Rec. 0.5
Depth (ft) B-22
N Rec.
B-21 B-22 francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY WEATEHRED ROCK
francis.abreu Text Box
NC 10
francis.abreu
SITE 10
2,630
2,635
2,640
2,645
2,650
2,655
2,660
2,665
2,670
2,675
2,630
2,635
2,640
2,645
2,650
2,655
2,660
2,665
2,670
2,675
1.6
1.5
1.8
1.5
1.4
1.5
2.0
1.8
1.5
1.7
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
Depth (ft) B-23
N Rec.
B-23 francis.abreu Line francis.abreu Text Box
FILL
francis.abreu Line francis.abreu Text Box
RESIDUUM
francis.abreu Line francis.abreu Text Box
HIGHLY WEATEHRED ROCK
francis.abreu Line francis.abreu Text Box
ROCK
francis.abreu Text Box
NC 11
francis.abreu
SITE 11
2,946
2,948
2,950
2,952
2,954
2,956
2,958
2,960
2,962
2,964
2,966
2,968
2,970
2,972
2,974
2,946
2,948
2,950
2,952
2,954
2,956
2,958
2,960
2,962
2,964
2,966
2,968
2,970
2,972
2,974
1.9
1.8
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
1.4
1.2
1.2
1.5
1.5
1.0
0.7
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
0.5
Depth (ft) B-24
N Rec.
0.5
Depth (ft) B-24A
N Rec.
0.5
3.5
24.7
Depth (ft) B-25
N Rec.
0.2
1.5
15.8
Depth (ft) B-25A
B-24
B-24A
B-25
B-25A francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box francis.abreu Text Box francis.abreu Polygonal Line francis.abreu Text Box francis.abreu Text Box
NC 12
francis.abreu Text Box
SITE 12
francis.abreu
HIGHLY WEATEHRED ROCK
2,940
2,945
2,950
2,955
2,960
2,965
2,970
2,975
2,980
2,985
2,990
2,940
2,945
2,950
2,955
2,960
2,965
2,970
2,975
2,980
2,985
2,990
1.0
0.8
0.7
0.8
1.5
1.6
1.2
1.3
1.5
1.3
0.6
1.7
1.2
0.7
0.2
1.7
1.5
0.7
1.3
0.7
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SM DECOMPOSED
ROCK
Groundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
1.3
8.5
Depth (ft) B-26
N Rec.
Depth (ft) B-26A 0.5
1.9 2.1
30.5
38.2
Depth (ft) B-27
N Rec.
0.5
1.5
10.7
Depth (ft) B-28
N Rec.
B-26B-26AB-27 B-28
francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM
francis.abreu Polygonal Line francis.abreu Text Box
HIGHLY WEATHERED ROCK
francis.abreu Text Box francis.abreu Text Box
NC 13
francis.abreu
SITE 13
3,136
3,138
3,140
3,142
3,144
3,146
3,148
3,150
3,152
3,136
3,138
3,140
3,142
3,144
3,146
3,148
3,150
3,152
50 0.2
1.7
0.7
1.5
1.9
1.6
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
DECOMPOSED
ROCK GRAVEL FILL SMGroundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C T
S
F S
\N C
\2
3- 1(
2) \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
\G
IN
T \N
C _E
R F
O _2
-1 (2
G
P J
Depth (ft) B-29
N Rec.
0.5
Depth (ft) B-30
N Rec.
B-29 B-30 francis.abreu Polygonal Line francis.abreu Text Box
FILL
francis.abreu Text Box francis.abreu Polygonal Line francis.abreu Text Box
RESIDUUM / HIGHLY WEATHERED ROCK
francis.abreu Polygonal Line francis.abreu Text Box
ROCK
francis.abreu Text Box
NC 14
francis.abreu
SITE 14
3,175
3,180
3,185
3,190
3,195
3,200
3,205
3,210
3,215
3,220
3,225
3,230
3,235
3,175
3,180
3,185
3,190
3,195
3,200
3,205
3,210
3,215
3,220
3,225
3,230
3,235
1.2
1.1
1.0
1.6
1.7
2.0
1.8
1.7
1.8
1.6
1.6
1.7
1.7
1.0
0.8
1.0
1.4
1.9
2.0
1.7
2.0
1.8
1.6
1.9
1.8
LEGEND
N SUBSURFACE PROFILE
SHEET NO.
E le va tio n (f t)
Groundwater depth encountered during drilling.
Rec.
STATE PROJECT
Rock Quality Designation (%)
E le va tio n (f t)
Recovery (ft)
RQD
THE BORING LOGS ON THIS SHEET REPRESENT THE SUBSURFACE CONDITIONS ENCOUNTERED
AT THE BORING LOCATIONS SHOWN. SUBSURFACE CONDITIONS MAY VARY BETWEEN THESE LOCATIONS.
Groundwater depth monitored after boring completion.
Standard Penetration Test Resistance in Blows per Foot
GRAVEL FILL SMGroundwater depth at boring completion.
U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL HIGHWAY ADMINISTRATION
EASTERN FEDERAL LANDS HIGHWAY DIVISION
STERLING, VIRGINIA
FSR NC ERFO 2013-1(2)
X
S
U B
S U
R F
A C
E P
R O
F
IL
E
/2 4/
:5
\\E F
L- F
IL
E
S H
A R
E .F
LH
D
.F H
W A
.D O
T .G
O V
\D A
T A
\P R
O
JE
C…
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