839CM3028_3030 Geotech Culpeper Bk A.pdf

Corporate HQ: 3015 Dumbarton Road Richmond, Virginia 23228 T 804.264.2701 F 804.264.1202 www.fandr.com

VIRGINIA • NORTH CAROLINA • SOUTH CAROLINA • MARYLAND • DISTRICT OF COLUMBIA

A Minority-Owned Business

Report of Geotechnical Study

Culpeper National Cemetery 305 US Avenue

Culpeper, Virginia F&R Project No. 74S-0126

Prepared For:

KCI Engineering of New York, PC 255 East Avenue

Suite 302 Rochester, New York 14604

Prepared By:

Froehling & Robertson, Inc.

10909 Houser Drive Fredericksburg, Virginia 22408

December 22, 2014

FROEHLING & ROBERTSON, INC.

Engineering Stability Since 1881

10909 Houser Drive

Fredericksburg, Virginia 22408 T 804-264-2701 I F 804-264-7862

Corporate HQ: 3015 Dumbarton Road Richmond, Virginia 23228 T 804.264.2701 F 804.264.1202 www.fandr.com

VIRGINIA • NORTH CAROLINA • SOUTH CAROLINA • MARYLAND • DISTRICT OF COLUMBIA

A Minority-Owned Business

F&R Project No. 74S-0126 December 22, 2014

Mr. Case Smeenk KCI Engineering of New York, PC 255 East Avenue Suite 302 Rochester, New York 14604

Reference: Culpeper National Cemetery 305 US Avenue Culpeper, Virginia

Dear Mr. Smeenk:

The purpose of this study is to present the final results of the subsurface exploration program and geotechnical engineering evaluation undertaken by Froehling & Robertson, Inc. (F&R) in connection with the Culpeper National Cemetery in Culpeper, Virginia. Our services were performed in general accordance with F&R Proposal No. 1574-00073 dated July 24, 2014 as authorized by you. The attached report presents our understanding of the project, reviews our exploration procedures, describes existing site and general subsurface conditions, and presents our geotechnical evaluations and recommendations.

We have enjoyed working with you on this project, and we are prepared to assist you with the recommended quality assurance monitoring and testing services during construction. Please contact us if you have any questions regarding this report or if we may be of further service.

Sincerely, FROEHLING & ROBERTSON, INC.

Jolie A. Erickson, E.I.T. Caleb M. Lange, P.E.

Staff Engineer Geotechnical Engineer

Reviewed by: Donald J. Sipher, P.E.

Senior Geotechnical Engineer

KCI Engineering of New York, PC Culpeper National Cemetery F&R File No. 74S-0126 December 22, 2014

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TABLE OF CONTENTS

SECTION PAGE

EXECUTIVE SUMMARY

1.0 PURPOSE & SCOPE OF SERVICES

2.0 PROJECT INFORMATION

2.1 SITE DESCRIPTION

2.2 PROPOSED CONSTRUCTION

3.0 EXPLORATION PROCEDURES

3.1 SUBSURFACE EXPLORATION

3.2 LABORATORY TESTING

3.3 INFILTRATION TESTING

4.0 REGIONAL GEOLOGY & SUBSURFACE CONDITIONS

4.1 REGIONAL GEOLOGY

4.2 SUBSURFACE CONDITIONS

4.2.1 General

4.2.2 Surficial Soils

4.2.3 Residual Soils

4.3 SUBSURFACE WATER

4.4 LABORATORY TEST RESULTS

4.5 INFILTRATION TEST RESULTS

5.0 GEOTECHNICAL DESIGN RECOMMENDATIONS

5.1 GENERAL

5.2 BEARING RECOMMENDATIONS

5.3 MODULUS OF SUBGRADE REACTION

5.4 LATERAL EARTH PRESSURES

5.5 SURFACE WATER/GROUNDWATER CONTROL

5.6 EXCAVATION CONDITIONS

6.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS

6.1 SITE PREPARATION

6.2 STRUCTURAL FILL PLACEMENT AND COMPACTION

6.3 CONSTRUCTION

6.4 SURFACE WATER/GROUNDWATER CONTROL

6.5 TEMPORARY EXCAVATION RECOMMENDATIONS

7.0 CONTINUATION OF SERVICES

8.0 LIMITATIONS

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APPENDICES

APPENDIX I

Site Vicinity Map (Drawing No. 1) Boring Location Plan (Drawing No. 2)

APPENDIX II

Key to Soil Classification Unified Soil Classification Chart Boring Logs

APPENDIX III

ASFE Document “Important Information about Your Geotechnical Engineering Report”

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EXECUTIVE SUMMARY

This Executive Summary is provided as a brief overview of our geotechnical engineering evaluation for the project and is not intended to replace more detailed information contained elsewhere in this report. As an overview, this summary inherently omits details that could be very important to the proper application of the provided geotechnical design recommendations. This report should be read in its entirety prior to implementation into design and construction

• The site was explored by four soil test borings performed on November 19, 2014. Site subsurface conditions generally consist of surficial soils underlain by residual soils.

• We recommend that a maximum allowable bearing pressure of 1,500 pounds per square foot (psf) be used for support of any structures.

• Subsurface water was not encountered at any of the borings performed for this subsurface exploration.

• Auger refusal was not encountered within any of the borings performed at the site.

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1.0 PURPOSE & SCOPE OF SERVICES

The purpose of the subsurface exploration and geotechnical engineering evaluation was to explore the subsurface conditions in the area of the new crypt field at Culpeper National Cemetery and provide geotechnical engineering design and construction recommendations.

F&R’s scope of services included the following:

• Completion of four soil test borings to a depth of 15 feet below the existing ground surface;

• Perform infiltration testing at each of the four locations to a depth of 7 feet below the existing ground surface;

• Preparation of typed Boring Logs;

• Performing a geotechnical engineering evaluation of the subsurface conditions with regard to their suitability for excavation and grading purposes;

• Preparation of this geotechnical report.

Our scope of services did not include a survey of the boring location, quantity estimates, preparation of plans or specifications, or the identification and evaluation of wetland or other environmental aspects of the project site.

2.0 PROJECT INFORMATION

2.1 Site Description

Culpeper National Cemetery is located at 305 US Avenue in Culpeper, Virginia (Drawing 1, Appendix I). The project site consists of a landscaped, grassy area on the west side of the south section of the existing cemetery. The site topography generally slopes down from east to west.

2.2 Proposed Construction

Project information was provided by email and phone and included the design proposal dated May 23, 2014. We understand the geotechnical exploration is to be performed in support of the design required for the 3,000 pre-placed crypt conversion for Culpeper National Cemetery in Culpeper, Virginia. The plan for development includes burial crypt field installation within a 2½ acre area inside the cemetery.

Construction will include grading of the site as necessary for crypt installation and surrounding surface drainage. Subsurface information presented herein includes soil types, soil drainage capability, soil expansive qualities, and suitability of excavated onsite soil for reuse as fill.

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3.0 EXPLORATION PROCEDURES

3.1 Subsurface Exploration

The exploration program was performed on November 19, 2014 and consisted of four soil test borings designated B-1 through B-4. The borings were drilled to a depth of 15 feet below existing site grades. The boring locations were provided by the client and staked in the field by F&R personnel by measuring from existing site features as the provided plan indicated. The approximate locations of the borings are shown on the attached boring location plan (Drawing No.

2, Appendix I). In consideration of the methods used in their determination, the boring locations shown on the attached boring location plan should be considered approximate.

The soil test borings were performed in accordance with generally accepted practice using a truck-mounted CME-55 rotary drill rig, equipped with an automatic hammer. Hollow-stem augers were advanced to pre-selected depths, the center plug was removed, and representative soil samples were recovered with a standard split-spoon sampler (1 3/8 in. ID, 2 in. OD) in general accordance with ASTM D 1586, the Standard Penetration Test. For these tests, a weight of 140 pounds is freely dropped from a height of 30 inches to drive the split-spoon sampler into the soil. The number of blows required to drive the split-spoon sampler three consecutive 6-inch increments is recorded, and the blows of the last two increments are summed to obtain the Standard Penetration Resistance (N-value). The N-value provides a general indication of in-situ soil conditions and has been correlated with certain engineering properties of soils.

An automatic hammer was used to perform the Standard Penetration Test (SPT) on this project.

Research has shown that the Standard Penetration Resistance (N-value) determined by an automatic hammer is different than the N-value determined by the safety hammer method. Most correlations that are published in the technical literature are based on the N-value determined by the safety hammer method. This is commonly termed N60 as the rope and cathead with a safety hammer delivers about 60 percent of the theoretical energy delivered by a 140-pound hammer freely falling 30 inches. Several researchers have proposed correction factors for the use of hammers other than the safety hammer to correct the values to be equivalent to the safety hammer SPT N60-values. The correction is made using the following equation:

N60 = Nfield x CE

Nfield is the value recorded in the field and CE is the energy ratio for the hammer utilized in the field. The guidelines provided in the Performance and Use of the Standard Penetration Test in Geotechnical Engineering Practice manual, published by the Center for Geotechnical Practice and Research at the Virginia Polytechnic Institute and State University, recommend that a correction

Page - 4 -factor (CE) be used to covert Nfield values to N60 values, when using an automatic hammer. The N-values reported on the boring logs included in this report are the actual, uncorrected, field derived values (Nfield). It is recommended that corrected N60 values be used for engineering analysis. We recommend that a correction factor (CE) of 1.47 be used to convert Nfield values to N60 values for the particular machine used for this investigation.

Prior to demobilization, the boreholes were backfilled with auger cuttings. Periodic observation of the backfilled boring should be performed, as the boring backfill could settle over time resulting in subsidence of the ground around the borehole.

Representative portions of the split-spoon and bulk soil samples collected throughout the exploration program were placed in glass jars and bags, respectively, and were transported to our laboratory. In the laboratory, the soil samples were evaluated by a member of our engineering staff, in general accordance with techniques outlined in the visual-manual identification procedure (ASTM D 2488). The soil descriptions and classifications discussed in this report and shown on the attached boring logs are based on visual observation and should be considered approximate.

Copies of the boring logs, as well as classification procedures, are provided in Appendix II.

Soil samples recovered from this project will be stored at F&R’s office for a period of 60 days. The samples will be discarded after 60 days, unless prior notification is provided to us in writing.

3.2 Laboratory Testing

Our proposal included laboratory testing to aid in identifying and evaluating soils that may affect building design or construction. In accordance with our proposal, the following tests were performed on representative soil samples collected during our subsurface exploration.

o 8 Natural Water Content (ASTM D 2216) o 2 Atterberg Limits (ASTM D 4318) o 2 Particle Size Distribution (with Hydrometer) (ASTM D 6913) o 2 pH Testing

The laboratory test results are shown in Section 4.4.

3.3 Infiltration Testing

Water infiltration testing was performed in accordance with generally accepted practices within two feet of each boring location, B-1 through B-4. For the infiltration test, the bore hole was cased with a six-inch PVC pipe, to a depth of seven feet. The PVC pipe was placed vertically in the bore hole, and the annular space was backfilled with in-situ material.

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A Geotechnical engineer began infiltration testing after a 24-hour period. Water levels were measured to the nearest sixteenth of an inch. All measurements were recorded and reported as inches per hour.

To begin the testing, the PVC pipe was filled with water and measurements were recorded every 60 minutes. This procedure was then repeated three more times for a total of four one-hour tests.

The infiltration rate of underlying soils may be reported either as the average of all four tests or the value of the last test. The infiltration rate is reported as the value of the last test, and the results are listed in Section 4.5.

4.0 REGIONAL GEOLOGY & SUBSURFACE CONDITIONS

4.1 Regional Geology

Based on the Geologic Map of Virginia (1993), the project site lies within the Piedmont Physiographic Province of Virginia. The soils within the project site are mapped as an Upper Triassic-aged (201.3 to 237 million year old) Newark Supergroup formation. The soils within this formation are residual and consist of poorly-sorted non-marine sediments. Conglomerate and greenstone clasts are common, as well as red sandstone beds. Due to significant weathering, the soils are generally identified as silts or clays at upper elevations and gradually transition to more coarse-grained materials as elevations approach the parent bedrock. Our findings are characteristic of the highly weathered parent rock types mapped.

4.2 Subsurface Conditions

4.2.1 General

The subsurface conditions discussed in the following paragraphs and those shown on the attached boring logs represent an estimate of the subsurface conditions based on interpretation of the boring data using normally accepted geotechnical engineering judgments. The transitions between different soil strata are usually less distinct than those shown on the boring logs.

Although individual soil test borings are representative of the subsurface conditions at the boring locations on the dates shown, they are not necessarily indicative of subsurface conditions at other locations or at other times. Data from the specific soil test borings are shown on the attached boring logs in Appendix II.

Below the existing ground surface, the borings generally encountered residual soils. These materials are generally discussed in the following paragraphs.

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4.2.2 Surficial Soils

Surficial soil was encountered at the borings to depths ranging between 2 and 3 inches. Surficial soil is typically a dark-colored soil material containing roots, fibrous matter, and/or other organic components, and is generally unsuitable for engineering purposes. F&R has not performed laboratory testing to determine the organic content or other horticultural properties of the observed surficial soil materials. The term surficial soil is not intended to indicate suitability for landscaping and/or other purposes, but is intended as a general term for typically dark near surface soils that are often observed to contain some degree of organic matter. The surficial soil depths provided in this report are based on driller observations and should be considered approximate. We note that the transition from surficial soil to underlying materials may be gradual, and therefore the observation and measurement of surficial soil depths is subjective.

Actual surficial soil depths should be expected to vary across the site.

4.2.3 Residual Soils

Residual soils were encountered beneath the surficial soils, extending to the borings’ termination depths. These soils were generally described as SILT or Elastic SILT (ML or MH). The Standard penetration resistance (field N-value) in these fine-grained soils (SILTs) ranged from 5 to 19 blows per foot (bpf) and indicated these soils are firm to very stiff in consistency.

Two borings, B-2 and B-3, encountered a very stiff layer at the deepest part of the borings. The rest of the samples were all consistently in the firm-to-stiff range, with field N-values from 5 to 9 bpf.

4.3 Subsurface Water

The test borings were monitored during and after drilling operations to obtain short-term subsurface water information. Subsurface water was not observed during or immediately after completion of drilling. Cave-in depths were measured to range from as shallow as 9.7 feet at boring B-1 to as deep as 11.0 feet in boring B-4. Cave-in can be indicative of seepage, particularly in sandy soils. Please see the boring logs included in Appendix II for cave-in depths at each boring location. The borings drilled for infiltration testing were observed 24 hours after drilling, prior to infiltration testing, and subsurface water was not observed in the borings at that time.

It should be noted that the location of the subsurface water table could vary by several feet because of seasonal fluctuations in precipitation, evaporation, surface water runoff, local topography, and other factors not immediately apparent at the time of this exploration. Normally, the highest subsurface water levels occur in the late winter and spring and the lowest levels occur in the late summer and fall.

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4.4 Laboratory Test Results

As discussed in Section 3.2, laboratory testing was performed on representative soil samples collected during our subsurface exploration. The results from the laboratory testing are summarized in the tables below.

Boring Sample Depth (Feet)

LL/PI(a)

Passing #200

Sieve(b)

Natural Water

Content

USCS(c)

Class.

pH

Level

B-1 5.0-6.5 -- -- 51.5 MH* --

B-1 8.5-10.0 57/13 -- -- MH --

B-2 2.5-4.0 -- -- -- ML* 6.17

B-2 5.0-6.5 61/15 -- -- MH --

B-2 8.5-10.0 -- 69.0 -- MH* --

B-2 13.5-15.0 -- -- 29.2 MH* --

B-3 0.0-1.5 -- -- 22.7 MH* --

B-3 2.5-4.0 -- -- 43.7 ML* --

B-3 5.0-6.5 -- -- 45.2 ML* --

B-3 8.5-10.0 -- -- 56.7 ML* --

B-3 13.5-15.0 -- -- 25.0 ML* --

B-4 2.5-4.0 -- -- -- ML* 5.24

B-4 5.0-6.5 -- -- 48.1 ML* --

B-4 8.5-10.0 -- 79.8 -- ML* --

(a) Liquid Limit and Plasticity Index from Atterberg Limits test (ASTM D 4318)

(b) Percentage of fines (silt and/or clay) from #200 Sieve Wash (ASTM D 1140)

(c) Unified Soil Classification System *visually evaluated

4.5 Infiltration Test Results

The Particle-Size Analysis was performed in accordance with ASTM D422 (Standard Test Method for Particle-Size Analysis of Soils). Infiltration tests were performed and the results are listed in the table below.

Sample Infiltration

Rate (in/hour)

Sand

Silt

Clay % USDA Texture

B-1 0.688 -- -- -- --

B-2 0.125 31.2 51.6 17.2 Silt Loam

B-3 0.063 -- -- -- --

B-4 0.188 20.5 47.9 31.6 Clay Loam

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5.0 GEOTECHNICAL DESIGN RECOMMENDATIONS

5.1 General

The following evaluations and recommendations are based on our observations at the site, interpretation of the field data obtained during this exploration, as well as the field and laboratory data obtained during the previous exploration, and our experience with similar subsurface conditions and projects. Soil penetration data has been used to estimate an allowable bearing pressure and associated settlement using established correlations. Subsurface conditions in unexplored locations may vary from those encountered. If the structure’s location, loads, or elevations are changed or differ from those assumed, we should be notified and requested to confirm and, if necessary, re-evaluate our recommendations.

Design of a given structure is dependent on the proposed structural loads, soil conditions, and construction constraints such as proximity to other structures, etc. The subsurface exploration aids the geotechnical engineer in identifying the soil stratum appropriate for structural support.

This identification includes considerations with regard to both allowable bearing capacity and compressibility of the soil strata. In addition, since the method of construction greatly affects the soils intended for structural support, consideration must be given to the implementation of suitable methods of site preparation, fill compaction, and other aspects of construction.

5.2 Bearing Recommendations

Lawn crypt structures may be designed for an allowable bearing pressure of up to 1,500 pounds per square foot (psf). The completed structures should bear at least three feet below finished grades for shrink-swell considerations.

During construction of the proposed structures, an experienced geotechnical engineer or his/her representative should be on site to confirm that the in-situ bearing conditions at the bottom of each excavation are adequate for the design bearing pressure recommended in this report.

5.3 Modulus of Subgrade Reaction

Structural analyses and design of floor slabs may require the use of a vertical modulus of subgrade reaction (k). We note that typical practice for slab-on-grade design is to provide a “k” value based on published correlation with soil types and California Bearing Ratio (CBR) test values. Such correlations are based on empirical data from plate load tests. The plate load test sufficiently models typical floor and wheel loads that exert stresses on the order of 3 to 5 feet. Based on

Page - 9 -published correlations, we estimate that a design modulus of subgrade reaction (k) = 90 pci is appropriate for slab-on-grade design calculations.

5.4 Lateral Earth Pressures

The following information is provided to aid in analysis of soil loads on any below-grade walls.

Earth pressures on walls below grade are influenced by structural design of the walls, conditions of wall restraint, methods of construction and/or compaction, and the strength of the materials being restrained. The most common conditions assumed for earth retaining wall design are the active and at-rest conditions. Active conditions apply to relatively flexible earth retention structures, such as freestanding walls, where some movement and rotation may occur to mobilize soil shear strength. Walls that are rigidly restrained, such as basement, pit, pool and tunnel walls, should be designed for the structure requiring the use of at-rest earth pressures.

A third condition, the passive state, represents the maximum possible pressure when a structure is pushed against the soil, and is used in wall foundation design to help resist active or at-rest pressures. Because significant wall movements are required to develop the passive pressure, the total calculated passive pressure should be reduced by one-half to two-thirds for design purposes.

Since a specific application for the lateral earth pressure has not been provided, we have included our recommendations for active, at-rest, and passive parameters. The crushed stone parameters may be used provided that the backfill extends out from the bottom of the wall and within a 45-degree slope from the base of the wall.

Design Parameters Typical ML/MH VDOT No. 57 Stone

Moist unit weight of backfill 120 pcf 105 pcf

Angle of Internal Friction (ø) 19o 40o

Equivalent Fluid Unit Weight (pcf), Active 61 23

Equivalent Fluid Unit Weight (pcf), At Rest 80 38

Coefficient of Earth Pressure at Rest (Ko) 0.67 0.36

Coefficient of Passive Earth Pressure (Kp) 1.97 4.60

Coefficient of Active Earth Pressure (Ka) 0.51 0.22

Coefficient of Friction [Concrete on Soil](µ) 0.32 0.32

We anticipate that the onsite soils will be used to backfill around the crypt structures.

Subsequently, we have provided the typical onsite soil parameters for use on this project. If an

Page - 10 -open-graded stone is used (such as VDOT No. 57 Stone) a drainage system should be installed.

The drainage system can consist of a six-inch drain tile, surrounded by stone and wrapped in filter fabric. It should drain to daylight; however if the topography does not allow for this, it can be property contained using a sump pit and pumping it to daylight or a storm sewer if available. If there is the opportunity for water to exist under the crypts, such that buoyant forces will cause uplift, the crypts should be designed to resist these forces or a full drainage system should be installed with a backup power source for sump operated drainage.

The recommended equivalent fluid pressures were provided assuming that a constantly functioning drainage system is installed between below-grade walls and backfill material to reduce the potential for buildup of hydrostatic pressures resulting in lateral stresses in excess of those stated. If a functioning drainage system is not installed, then lateral earth pressures should be determined using the buoyant weight of the soil. Hydrostatic pressures calculated with the unit weight of water (62.4 pcf) should be added to these earth pressures to obtain the total stresses for design.

Surcharge loads should be evaluated using the appropriate active or at-rest pressure coefficients provided above. The effect of surcharge loads should be added to the recommended earth pressures to determine total lateral stresses.

5.5 Surface Water/Groundwater Control

Subsurface water for the purposes of this report is defined as water encountered below the existing ground surface. Based on the subsurface water data obtained during our exploration program at this time, we do not anticipate that subsurface water will be encountered during anticipated earthwork and shallow excavations.

An important aspect to consider during development of this site is surface water control. During the construction, we recommend that steps be taken to enhance surface flow away from any excavations and promote rapid clearing of rainfall and runoff water following rain events. It should be incumbent on the contractor to maintain favorable site drainage during construction to reduce deterioration of otherwise stable subgrades.

5.6 Excavation Conditions

Auger refusal materials were not encountered in the borings performed within the planned termination depth at the four borings drilled across the site. Based on the foregoing, difficult excavation conditions are not anticipated within the top eight feet of this site. F&R notes that the profile of the bedrock surface within the Piedmont region is typically irregular and variable, and

Page - 11 -that bedrock could be encountered at deeper or shallower depths between test boring locations and in unexplored areas of the site.

In mass excavations for general site work, hard or dense soils (soils with standard penetration resistances of 30 or more blows per foot) can usually be removed by ripping with a single-tooth ripper attached to a large crawler tractor, or by breaking it out with a tracked excavator or large front-end loader. In confined excavations such as is anticipated for the crypts, utility trenches, etc., removal of partially weathered rock typically requires use of large backhoes, pneumatic spades, hoe rams or pre-drilling and splitting.

The definition of rock can be a source of conflict during construction. The following definitions have been incorporated into specifications on other projects and are provided for your general guidance:

GENERAL EXCAVATION:

Rippable Rock - Any material that cannot be removed by scrapers, loaders, pans, dozers, or graders; and requires the use of a single-tooth ripper mounted on a crawler tractor having a minimum draw bar pull rated at not less than 56,000 pounds.

Blast Rock - Any material which cannot be excavated with a single-tooth ripper mounted on a crawler tractor having a minimum draw bar pull rated at not less than 56,000 pounds (Caterpillar D-8K or equivalent) or by a Caterpillar 977 front-end loader or equivalent; and occupying an original volume of at least one (1) cubic yard.

TRENCH EXCAVATION:

Blast Rock - Any material which cannot be excavated with a backhoe having a bucket curling force rated at not less than 25,700 pounds (e.g.

Caterpillar Model 315 or equivalent), and occupying an original volume of at least one-half (1/2) cubic yard.

6.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS

6.1 Site Preparation

Before proceeding with construction, any utilities, existing pavements, concrete sidewalks, surficial soils, and other deleterious non-soil materials (if any) should be stripped or removed from the proposed construction area. Attention should be given to these areas to ensure all unsuitable

Page - 12 -material is removed prior to continuing with construction. During the stripping operations, positive surface drainage should be maintained to prevent the accumulation of water.

Particular attention should be given to any utility trenches within the proposed additions’ footprints. For obvious reasons, existing underground utility trenches were avoided in our drilling program. Our experience is that utility trenches are sometimes backfilled with very little compactive effort. Where utility lines are removed, the trench subgrade should be verified by an F&R representative prior to backfilling in accordance with the controlled structural fill recommendations provided in the following section of this report.

After stripping, areas intended to support lawn crypts and new fill should be carefully evaluated by a geotechnical engineer. Areas intended for slab-on-grade support should be proofrolled with a 20- to 30-ton loaded truck, or other pneumatic-tired vehicle of similar size and weight, under the observation of the geotechnical engineer. A 1.5 ton trench roller can be used to proofroll areas that cannot be accessed by a truck, such as the bottoms of excavations and utility trenches.

Proofrolling should be performed during a time of good weather and not while the site is wet, frozen, or severely desiccated.

The proofrolling observation is an opportunity for the geotechnical engineer to locate inconsistencies intermediate of our boring locations in the existing subgrade, especially near existing utilities, where poor-quality fill may exist and where new fill placement and subgrade structures are proposed. Any unsuitable materials observed during the evaluation and proofrolling operations should be undercut and replaced with structural fill or stabilized in-place.

Undercut areas should be backfilled with structural fill or lean concrete. Open-graded stone (such as VDOT 57 Stone) should not be used for backfilling where water can collect within the backfilled stone. See Section 6.3 of this report for further details. The actual need for, and extent of, undercutting and/or in-place stabilization required can best be determined in the field by the geotechnical engineer at the time of construction.

6.2 Structural Fill Placement and Compaction

The onsite material can be used for fill. However, based on the USCS classifications of onsite soil, difficulty with moisture control during construction is expected. Granular fill, such as VDOT 57 Stone, may be used for backfill if desired. If granular material is used as backfill, it is recommended to cap the fill with 12 inches of low permeability soil, such as MH or CH, to help reduce water infiltration behind the wall. Other materials may be suitable for use as general fill materials that are to be placed in landscaped areas, and should be individually evaluated by the geotechnical

Page - 13 -engineer. Controlled structural fill should be free of boulders, organic matter, debris, or other deleterious materials and should have a maximum particle size no greater than three inches.

We recommend that structural fill be compacted to at least 95 percent of the Standard Proctor (ASTM D 698 or AASHTO T 99) maximum dry density and that the moisture content be maintained within three percentage points of the optimum moisture content, as determined from the Standard Proctor density test. Fill materials should be placed in horizontal lifts with maximum height of 8 inches loose measure. New fill should be adequately keyed into stripped and scarified subgrade soils. During fill operations, positive surface drainage should be maintained to prevent the accumulation of water. In confined areas such as may be used for this project, portable compaction equipment and thin lifts of three to four inches may be required to achieve the specified degree of compaction.

Generally, we do not anticipate significant problems controlling moistures within approved fill during periods of dry weather, but moisture control may be difficult during winter months or extended periods of rain. We recommend that the contractor have equipment on site during earthwork for both drying and wetting of fill soils. Attempts to work the soils when wet can be expected to result in deterioration of otherwise suitable soil conditions or of previously placed and properly compacted fill.

If construction traffic or weather has disturbed the subgrade, the upper 8 inches of soils intended for structural support should be scarified and re-compacted. Each lift of fill should be tested to confirm that the recommended degree of compaction is attained. In confined areas, a greater frequency may be required.

6.3 Construction

All subgrades intended to support structures should be observed, evaluated, and verified for the design bearing pressure by the geotechnical engineer after excavation and prior to reinforcement steel placement. We anticipate that low consistency soils may be encountered during excavation, and localized undercutting and/or in-place stabilization of bearing subgrades may be required.

The actual need for, and extent of, undercutting should be based on field observations made by the geotechnical engineer or his/her representative at the time of construction. To aid in identifying unsuitable soils, we recommend that a dynamic cone penetrometer (DCP) be used at the bottom of any excavations.

Excavations in areas intended to support crypts should be made in such a way as to provide bearing surfaces that are firm and free of loose, soft, wet, or otherwise disturbed soils. If plastic concrete is used, it should not be placed on frozen or saturated subgrades. If such materials are

Page - 14 -allowed to remain below field-placed concrete, settlements will increase. Excavations should be concreted as soon as practical after they are excavated. If an excavation is left open for an extended period, a thin mat of lean concrete should be placed over the bottom to minimize damage to the bearing surface from weather or construction activities. Water should not be allowed to pond in any excavation.

In a dry and undisturbed state, the subgrade soils at the site will provide suitable subgrade support for fill placement and construction operations. However, when wet, the soil can degrade quickly either with or without disturbance from contractor operations. Therefore, good site drainage should be maintained during earthwork operations to help maintain the stability of the soil.

Attempting site work during adverse seasonal conditions will have significant effect on the site work budget, as substantially more undercutting will be required. Ideally, earthwork should be performed during the summer or early fall (typically drier and warmer months).

6.4 Surface Water/Groundwater Control

Subsurface water for the purposes of this report is defined as water encountered below the existing ground surface. Even though no subsurface water was encountered during drilling, there is a possibility that rainwater may collect in structural excavations. If this occurs, sump pits and pumps can be used to remove water from excavations, and the contractor should be equipped to do so.

Below-grade walls should be constructed using either a free-draining material as backfill or a drainage system. The drainage system can tie into a perimeter drain and run to daylight.

An important aspect to consider during development of this site is surface water control. During the construction, we recommend that steps be taken to enhance surface flow away from any excavations and promote rapid clearing of rainfall and runoff water following rain events. It should be incumbent on the contractor to maintain favorable site drainage during construction to reduce deterioration of otherwise stable subgrades.

6.5 Temporary Excavation Recommendations

Mass excavations and other excavations required for construction of this project must be performed in accordance with the United States Department of Labor, Occupational Safety and Health Administration (OSHA) guidelines (29 CFR 1926, Subpart P, Excavations) or other applicable jurisdictional codes for permissible temporary side-slope ratios and/or shoring requirements. The OSHA guidelines require daily inspections of excavations, adjacent areas and protective systems by a competent person for evidence of situations that could result in cave-ins, indications of failure of

Page - 15 -a protective system, or other hazardous conditions. All excavated soils, equipment, building supplies, etc., should be placed away from the edges of the excavation at a distance equaling or exceeding the depth of the excavation. F&R cautions that the actual excavation slopes will need to be evaluated frequently each day by the competent person and flatter slopes or the use of shoring may be required to maintain a safe excavation depending upon excavation-specific circumstances.

The contractor is responsible for providing the competent person and all aspects of site excavation safety. F&R can evaluate specific excavation slope situations if we are informed and requested by the owner, designer or contractor’s competent person.

7.0 CONTINUATION OF SERVICES

We recommend that we be given the opportunity to review project plans and specifications when construction documents approach completion. This review evaluates whether the recommendations and comments provided herein have been understood and properly implemented. We also recommend that Froehling & Robertson, Inc. be retained for professional and construction materials testing services during construction of the project. Our continued involvement on the project helps provide continuity for proper implementation of the recommendations discussed herein.

The Geotechnical Engineer of Record should be retained to monitor and test earthwork activities and excavations. It should be noted that the actual soil conditions at the various subgrade levels will vary across this site and thus the presence of the Geotechnical Engineer and/or the engineer’s representative during construction will serve to validate the subsurface conditions and recommendations presented in this report. We recommend that F&R be employed to monitor the earthwork construction, and to report that the recommendations contained in this report are completed in a satisfactory manner. Our involvement on the project will aid in the proper implementation of the recommendations discussed herein. The following is a recommended scope of services:

• Review of project plans and construction specifications to verify that the recommendations presented in this report have been properly interpreted and implemented;

• Observe and perform testing during earthwork to document that subsurface conditions encountered during construction are consistent with those anticipated in this report;

• Observe subgrade preparation including any proofrolling operations, undercutting of soft/loose unsuitable soils, installation of drainage materials, geotextiles and fill placement;

Page - 16 -

• Observe all excavations and bearing grades for compliance with the geotechnical recommendations;

• and provide Construction Materials Testing.

These services are not included in our current scope of services and can be rendered for an additional cost.

8.0 LIMITATIONS

This report has been prepared for the exclusive use of KCI Engineering of New York, PC or their agent, for specific application to the Culpeper National Cemetery project, in accordance with generally accepted soil and foundation engineering practices. No other warranty, express or implied, is made. Our evaluations and recommendations are based on design information furnished to us, the data obtained from the previously described subsurface exploration program, and generally accepted geotechnical engineering practice. The evaluations and recommendations do not reflect variations in subsurface conditions which could exist intermediate of the boring locations or in unexplored areas of the site. Should such variations become apparent during construction, it will be necessary to re-evaluate our recommendations based upon on-site observations of the conditions.

There are important limitations to this and all geotechnical studies. Some of these limitations are discussed in the information prepared by ASFE, which is included in Appendix III. We ask that you please review this ASFE information.

Regardless of the thoroughness of a subsurface exploration, there is the possibility that conditions between borings will differ from those at the boring locations, that conditions are not as anticipated by the designers, or that the construction process has altered the soil conditions.

Therefore, experienced geotechnical engineers should evaluate earthwork, pavement, and foundation construction to verify that the conditions anticipated in design actually exist.

Otherwise, we assume no responsibility for construction compliance with the design concepts, specifications, or recommendations.

In the event that changes are made in the design or location of the proposed structure, the recommendations presented in the report shall not be considered valid unless the changes are reviewed by our firm and conclusions of this report modified and/or verified in writing. If this report is copied or transmitted to a third party, it must be copied or transmitted in its entirety, including text, attachments, and enclosures. Interpretations based on only a part of this report may not be valid.

APPENDIX I

SITE VICINITY MAP

Drawing No. 1

Project No: 74S-0126 Client: KCI Engineering of New York, PC Project: Culpeper National Cemetery City/State: Culpeper, Virginia

Source: Google Maps Scale: As Shown Date: November 2014

Approximate Site Location

BORING LOCATION PLAN

Drawing No. 2

Project No: 74S-0126 Client: KCI Engineering of New York, PC Project: Culpeper National Cemetery City/State: Culpeper, Virginia

Source: Google Earth Scale: As Shown Date: November 2014

- Approximate Boring Locations

B-1

B-3

B-2

B-4

APPENDIX II

KEY TO SOIL CLASSIFICATION

Correlation of Penetration Resistance with

Relative Density and Consistency

Sands and Gravels Silts and Clays No. of Relative No. of Relative Blows, N Density Blows, N Density 0 - 4 Very loose 0 - 2 Very soft 5 - 10 Loose 3 - 4 Soft 11 - 30 Medium dense 5 - 8 Firm 31 - 50 Dense 9 - 15 Stiff Over 50 Very dense 16 - 30 Very stiff 31 - 50 Hard Over 50 Very hard

Particle Size Identification

(Unified Classification System) Boulders: Diameter exceeds 12-in. (300-mm)

Cobbles: 3-in. (75-mm) to 12-in. (300-mm) diameter

Gravel: Coarse - ¾-in. (19-mm) to 3 in. (75-mm) diameter Fine - No. 4 (4.75-mm) sieve to ¾-in. (19-mm) diameter

Sand: Coarse – No. 10 (2.0-mm) to No. 4 (4.76 mm) sieve Medium – No. 40 (0.425-mm) to No. 10 (2.0-mm) sieve Fine - No. 200 (0.075-mm) to No. 40 (0.425-mm) sieve

Silt and Clay: Less than No. 200 (0.075-mm) sieve

Modifiers

The modifiers provide our estimate of the amount of silt, clay or sand size particles in the soil sample.

Approximate Content

Modifiers

Field Moisture Description

≤ 5%: Trace Dry Absence of moisture, dusty, dry to touch

5 to 10%: Few Moist Damp but no visible water

15 to 25%: Little Wet Visible free water, usually soil is below water table 30 to 45%: Some

50 to 100% Mostly

1.5

4.0

6.5

10.0

15.0

No groundwater was encountered during drilling.

Cave-in depth 9.7'

2 inches of surficial soil RESIDUAL: stiff, red-brown elastic SILT with little coarse sand - moist

(MH)

stiff, red-brown, SILT with coarse sand - moist

(ML)

Boring terminated at 15 feet.

Boring backfilled upon completion.

0.0

2.5

5.0

8.5

13.5

0.2

12.0

15.0

3-4-5

2-3-5

3-3-4

3-3-4

4-3-4

Froehling & Robertson, Inc.

Client: KCI Engineering of New York, PC

City/State: Culpeper, Virginia Project: Culpeper National Cemetery

*Number of blows required for a 140 lb hammer dropping 30" to drive 2" O.D., 1.375" I.D. sampler a total of 18 inches in three 6" increments.

The sum of the second and third increments of penetration is termed the standard penetration resistance, N-Value.

Project No: 74S-0126

Elevation Remarks

Boring: B-1 (1 of 1)

Location: See Boring Location Plan Hammer Type: Automatic

N-Value (blows/ft)

Sample Depth (feet)

Depth

R

Total Depth: 15.0' Elevation:

Driller: Martin

BORING LOG

Drilling Method: HSA 3-1/4" ID

Date Drilled: 11/19/14

* Sample Blows

Description of Materials (Classification)

BO

RI

N G

_L O

G

4S -0

6.

G

PJ

F

R.

G

D T

2/

/1

6.5

10.0

15.0

No groundwater was encountered during drilling.

Cave-in depth 10.2'

3 inches of surficial soil RESIDUAL: stiff, red-brown, elastic SILT with some coarse sand - moist

(MH)

firm to stiff, red-brown, elastic SILT - moist

(MH)

stiff to very stiff, yellow-brown with black foliation, sandy elastic SILT - moist

(MH)

Boring terminated at 15 feet.

Boring backfilled upon completion.

0.0

2.5

5.0

8.5

13.5

0.3

2.0

7.0

15.0

3-4-5

2-3-5

2-2-3

2-3-5

3-5-7

Froehling & Robertson, Inc.

Client: KCI Engineering of New York, PC

City/State: Culpeper, Virginia Project: Culpeper National Cemetery

*Number of blows required for a 140 lb hammer dropping 30" to drive 2" O.D., 1.375" I.D. sampler a total of 18 inches in three 6" increments.

The sum of the second and third increments of penetration is termed the standard penetration resistance, N-Value.

Project No: 74S-0126

Elevation Remarks

Boring: B-2 (1 of 1)

Location: See Boring Location Plan Hammer Type: Automatic

N-Value (blows/ft)

Sample Depth (feet)

Depth

R

Total Depth: 15.0' Elevation:

Driller: Martin

BORING LOG

Drilling Method: HSA 3-1/4" ID

Date Drilled: 11/19/14

* Sample Blows

Description of Materials (Classification)

BO

RI

N G

_L O

G

4S -0

6.

G

PJ

F

R.

G

D T

2/

6.5

10.0

15.0

No groundwater was encountered during drilling.

Cave-in depth 10.0'

3 inches of surficial soil RESIDUAL: stiff, red-brown, elastic SILT with trace coarse sand - moist

(MH)

firm to stiff, red-brown and yellow-brown, SILT -moist

(ML)

stiff, yellow-brown and dark brown, SILT - moist

(ML)

very stiff, red-brown and yellow with black foliation, SILT with some medium sand - moist

(ML)

Boring terminated at 15 feet.

Boring backfilled upon completion.

0.0

2.5

5.0

8.5

13.5

0.3

2.0

7.0

12.0

15.0

3-4-5

3-3-5

2-2-3

2-2-5

4-5-14

Froehling & Robertson, Inc.

Client: KCI Engineering of New York, PC

City/State: Culpeper, Virginia Project: Culpeper National Cemetery

*Number of blows required for a 140 lb hammer dropping 30" to drive 2" O.D., 1.375" I.D. sampler a total of 18 inches in three 6" increments.

The sum of the second and third increments of penetration is termed the standard penetration resistance, N-Value.

Project No: 74S-0126

Elevation Remarks

Boring: B-3 (1 of 1)

Location: See Boring Location Plan Hammer Type: Automatic

N-Value (blows/ft)

Sample Depth (feet)

Depth

R

Total Depth: 15.0' Elevation:

Driller: Martin

BORING LOG

Drilling Method: HSA 3-1/4" ID

Date Drilled: 11/19/14

* Sample Blows

Description of Materials (Classification)

BO

RI

N G

_L O

G

4S -0

6.

G

PJ

F

R.

G

D T

2/

6.5

10.0

15.0

No groundwater was encountered during drilling.

Cave-in depth 11.0'

3 inches of surficial soil RESIDUAL: stiff, red-brown, elastic SILT with some gravel and coarse sand - moist

(MH)

stiff, red-brown, SILT - moist

(ML)

stiff, brown and yellow-brown with black foliation, elastic SILT with trace coarse sand -moist

(MH)

Boring terminated at 20 feet.

Boring backfilled upon completion.

0.0

2.5

5.0

8.5

13.5

0.3

2.0

12.0

15.0

2-5-3

3-3-5

3-3-5

2-3-4

4-4-4

Froehling & Robertson, Inc.

Client: KCI Engineering of New York, PC

City/State: Culpeper, Virginia Project: Culpeper National Cemetery

*Number of blows required for a 140 lb hammer dropping 30" to drive 2" O.D., 1.375" I.D. sampler a total of 18 inches in three 6" increments.

The sum of the second and third increments of penetration is termed the standard penetration resistance, N-Value.

Project No: 74S-0126

Elevation Remarks

Boring: B-4 (1 of 1)

Location: See Boring Location Plan Hammer Type: Automatic

N-Value (blows/ft)

Sample Depth (feet)

Depth

R

Total Depth: 15.0' Elevation:

Driller: Martin

BORING LOG

Drilling Method: HSA 3-1/4" ID

Date Drilled: 11/19/14

* Sample Blows

Description of Materials (Classification)

BO

RI

N G

_L O

G

4S -0

6.

G

PJ

F

R.

G

D T

2/

APPENDIX III

Geotechnical Services Are Performed forSpecific Purposes, Persons, and ProjectsGeotechnical engineers structure their services to meet the specific needs oftheir clients. A geotechnical engineering study conducted for a civil engi-neer may not fulfill the needs of a construction contractor or even anothercivil engineer. Because each geotechnical engineering study is unique, eachgeotechnical engineering report is unique, prepared solely for the client. Noone except you should rely on your geotechnical engineering report withoutfirst conferring with the geotechnical engineer who prepared it. And no one— not even you — should apply the report for any purpose or projectexcept the one originally contemplated.

Read the Full ReportSerious problems have occurred because those relying on a geotechnicalengineering report did not read it all. Do not rely on an executive summary.Do not read selected elements only.

A Geotechnical Engineering Report Is Based on A Unique Set of Project-Specific FactorsGeotechnical engineers consider a number of unique, project-specific fac-tors when establishing the scope of a study. Typical factors include: theclient's goals, objectives, and risk management preferences; the generalnature of the structure involved, its size, and configuration; the location ofthe structure on the site; and other planned or existing site improvements,such as access roads, parking lots, and underground utilities. Unless thegeotechnical engineer who conducted the study specifically indicates oth-erwise, do not rely on a geotechnical engineering report that was:• not prepared for you,• not prepared for your project,• not prepared for the specific site explored, or• completed before important project changes were made.

Typical changes that can erode the reliability of an existing geotechnicalengineering report include those that affect: • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse,

• elevation, configuration, location, orientation, or weight of the proposed structure,• composition of the design team, or• project ownership.

As a general rule, always inform your geotechnical engineer of projectchanges—even minor ones—and request an assessment of their impact.Geotechnical engineers cannot accept responsibility or liability…