W912HV-16-B-0004MWD_APPENDIX_-_vol3.pdf

SOLICITATION NO. W912HV-16-B-0004

DATE: JULY 2016

U.S. ARMY CORPS OF ENGINEERS

JAPAN ENGINEER DISTRICT

VOLUME 3 OF 3

FY-16 MILITARY WORKING DOG FACILITIES

(CAMP HANSEN)

Project No. P606

Camp Hansen, Okinawa, Japan

APPENDIX

CONSTRUCTION SOLICITATION AND SPECIFICATIONS

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Geotechnical Investigation Report FY16 Marine Corps MILCON Project Military Working Dog Facility

US Army Corps of Engineers Contract No. W912HV-14-D-0002

FINAL

17 August 2015

Prepared For:

Department of the Army Albuquerque District, Corps of Engineers

4101 Jefferson Plaza NE Albuquerque, New Mexico 87109-3435

Prepared by:

Otsuki Sekkei Co., Ltd.

410 Aza Shimabukuro

Kitanakagusuku Son, Okinawa, Japan 901-2301

TEL (098) 930-5690 FAX (098) 930-5692

In conjunction with:

Geotechnical Investigation Report i Military Working Dog Facility W912HV-14-D-0002 Camp Hansen, Okinawa, Japan

EXECUTIVE SUMMARY

This report represents the findings of a geotechnical investigation conducted from 8 to 20 May 2015 by Otsuki Sekkei Co., Ltd (OSK) at the FY16 Marine Corps Military Construction (MILCON) Military

Working Dog (MWD) project site in Camp Hansen, Okinawa, Japan under US Army Corps of Engineers (USACE) contract number W912HV-14-D-0002. The purpose of the geotechnical investigation is to provide geotechnical information and site recommendations to aid in the design of the new facility by others.

Geologic Site Hazards and Site Class

Screening for geological site hazards to include susceptibility to liquefaction, slope failure, settlement was conducted for the existing MWD Site. Based on soil boring data, a seismic site class designation was established for the project site.

Subsurface conditions and available Okinawa Prefectural Government information indicate that the potential for liquefaction is low. Observations of existing site conditions did not indicate any potential issues of instability of existing natural slopes. And since there are currently no existing structures in the vicinity of the MWD site, no ground settlement issues were observed. Based on the future floor elevation (FFE) information provided, new fill loads are anticipated to cause both short-term and long-term settlements at each of the facilities which are detailed in Section 6 of the report and described in MWD Earthwork Considerations below.

Boring log observations and SPT results indicate that the site soils fit the Site Class “E” designation for seismic considerations. The thickness of soft intermediate soil layers presenting low SPT N-values encountered within the top 30 m of soils were factors in selecting a Site Class “E” designation for the MWD site.

Details on geological site hazards and site class determination are described in Sections 4.2 and

4.3 of this report.

MWD Earthwork Considerations

Earthwork for this site will comprise of cut operations of up to 1 to 2 m in the north and east portions of the site and under the northeast portion of the proposed Kennel 1 facility. Fill operations of up to 3 m is expected predominantly in the southern, central, and western portions of the project site. Filling operations will occur under each of the 3 proposed facilities to varying extent. Due to the cutting and filling required at the site, retaining structures are assumed to be required to the north and east of the Kennel 1 facility.

Due to the introduction of new fill loads to the site, differential settlement shall be controlled by allowing settlement to stabilize after filling operations occur. The Kennel 1 facility is estimated to undergo approximately 120 mm of settlement due to fill of up to 2.5m. It is anticipated that

Geotechnical Investigation Report ii Military Working Dog Facility most settlement may occur rapidly, approximately within one week of the completion of fill operations.

However, at the Administration Building and Kennel 2, settlements due to long-term consolidation should also be considered due to underlying compressible soil layers. At the Administration Building and Kennel 2 facilities, settlements along the order of 250 mm are anticipated due to fill of up to 3 m. It is estimated that 50% of the settlement will occur within the first 30 days following completion of up to 3 m of fill placement. For this reason, it is recommended that in the case of the shallow foundation option, foundation structures and underground utilities should not be constructed within a 1-month period of the completion of filling and until settlements have been stabilized.

MWD Facility Foundation Recommendations

Shallow foundations are recommended for the Kennel 1 and Kennel 2 facilities at the allowable bearing pressures presented in this report. However, for the Administration facility, a pile foundation is recommended for reasons stated later in this section.

Recommended allowable bearing pressures for shallow foundations were calculated considering site soil layer characteristics and estimated new fill loads for each MWD facility based on the existing and future topography of the site. For Kennel 1 and Kennel 2, the allowable bearing pressure for shallow foundations (assuming continuous footings) is recommended to be 50 KN/m2 and 70 KN/m2, respectively. The width of footings should be considered by the designer to accommodate for the allowable bearing pressures presented in this report.

Undocumented existing fill of 3 to 5 m thickness at the proposed Administration Building area may present significant settlement issues due to the uncertainty of fill soils quality and engineering behavior, inconsistency of material distribution and grade of compaction, and the existence of concrete and other organic debris observed within the layer during the site investigation. Removal or soil treatment of existing undocumented fill of this large thickness is cost prohibitive and therefore a pile foundation for the Administration Building is recommended.

Due to the absence of suitable intermediate layers for friction piles, it is recommended that end-bearing piles be used. In addition, pile foundations will allow construction of foundation elements such as pile installation and pile caps to begin without delay, in contrast with shallow foundations which require more time for stabilization of settlements imposed by new fill loads to occur.

The suitable bearing stratum for piles at the Administration facility site is the highly dense heavily weathered sandstone bedrock layer [Silty sand (SM)] displaying consistent SPT N-values of 50 blows. Assuming depth to pile caps are approximately 1 m below the FFE, the estimated pile lengths at the Administration Building are from 20 to 22m in total length.

MWD Floor Slab Recommendations

As previously mentioned, undocumented existing fill of 3 to 5m thickness at the proposed Administration Building area may present significant settlement issues due to the uncertainty of

Geotechnical Investigation Report iii Military Working Dog Facility fill soil quality and engineering behavior and the existence of concrete and other organic debris within this layer. Risks for excessive differential settlement due to the above conditions, if it occurs, will disqualify the use of a conventional slab-on-grade floor slab system. It is therefore recommended to use a structural slab for the Administration Building to prevent possible settlement issues of the floor slab.

Due to the relative absence of undocumented fill at the proposed Kennel facility areas and considering construction quality control of new filling operations at the MWD site, a slab-on-grade floor slab system for the Kennel facilities is considered appropriate.

MWD Pavement Recommendations

As part of the geotechnical investigation, seven soil samples for CBR tests were extracted at locations representative for proposed pavement areas for the development of flexible and rigid pavement design recommendations. Due to low CBR test values observed in areas near to proposed future parking areas, it is recommended that improvement of the existing subgrade be conducted to improve the design CBR value to 3. Based on an improved design CBR for subgrade of 3, the following pavement sections are recommended based UFC 3-240-01FA, "Pavement Design for Roads, Streets, Walks and Open Storage Areas", dated on 16 January 2004.

SUMMARY FOR FLEXIBLE PAVEMENT RECOMMENDATIONS

Site Area

Bituminous Pavement Thickness

(mm)

Base Course Thickness

(mm)

Subbase Thickness

(mm)

Total Pavement Thickness

(mm)

Subgrade Replacement

Thickness (mm)

Northwest Parking Areas

50 150 180 380 300

SUMMARY FOR RIGID PAVEMENT RECOMMENDATIONS

Site Area PCC layer Thickness

(mm)

Base Course Thickness

(mm)

Total Pavement Thickness

(mm)

Subgrade Replacement

Thickness (mm)

Northwest Parking Areas 150 150 300 300

Details for flexible and rigid pavement recommendations are presented in Section 7.3 of this report.

Geotechnical Investigation Report iv Military Working Dog Facility

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Geotechnical Investigation Report v Military Working Dog Facility

TABLE OF CONTENTS

EXECUTIVE SUMMARY ................................................................................................................ I

ACRONYMS AND ABBREVIATIONS .................................................................................... VIII

1.0 PURPOSE AND SCOPE

2.0 PROJECT OVERVIEW

2.1 Project Team

2.2 Site Location

2.3 Description of The Geotechnical Investigation

2.4 Vertical & Horizontal Coordinate Survey

3.0 SITE GEOGRAPHICAL AND GEOLOGICAL FEATURES

3.1 Geographical features

3.2 Geological features

4.0 SITE CONDITIONS

4.1 Subsurface Conditions

4.1.1 Subsurface Profile of the Site

4.1.2 Groundwater

4.1.3 Subsurface Variations

4.2 Geological Site Hazards

4.2.1 Soil Liquefaction Potential

4.2.2 Potential Slope Instability and Settlement

4.3 Seismic Site Class Designation

5.0 FIELD EFFORT

5.1 Soil Borings and Standard Penetration Testing

5.2 Soils Laboratory Testing

6.0 CONCLUSIONS & RECOMMENDATIONS

6.1 Foundation Recommendations

6.1.1 Shallow Foundation Option

6.1.2 Deep Foundation Option

6.2 Floor Slab Recommendations

6.3 Retaining Wall Recommendations

6.4 Flexible and Rigid Pavement Recommendations

7.0 CONSTRUCTION CONSIDERATIONS

7.1 Earthwork and Grading

7.2 Site Drainage

Geotechnical Investigation Report vi Military Working Dog Facility

7.3 Excavation and Trenching

7.4 Construction Considerations For Pavements

8.0 REFERENCES

9.0 JAPANESE TRANSLATIONS (日本語訳)

TABLES

TABLE 1: SOIL BORINGS SUMMARY

TABLE 2: SOIL LABORATORY TESTING SUMMARY

TABLE 3: SOIL PROPERTIES TEST RESULTS SUMMARY

TABLE 4: MODIFIED PROCTOR / COMPACTION TESTING RESULTS

TABLE 5: 1D CONSOLIDATION AND UNIAXIAL COMPRESSION RESULTS

TABLE 6: DESIGN CBR RESULTS

TABLE 7: CBR RESULTS OF LABORATORY COMPACTED SOILS AT OPT WC

TABLE 8: BEARING STRATUM ELEVATION & ESTIMATED PILE LENGTH

TABLE 9: ALLOWABLE BEARING CAPACITY FOR PILE FOUNDATIONS

TABLE 10: SOIL PARAMETERS FOR RETAINING WALLS (LEVEL BACKFILL)

TABLE 11: SOIL PARAMETERS FOR RETAINING WALLS (SLOPED BACKFILL 2:1,

H:V)

TABLE 12: FLEXIBLE PAVEMENT DESIGN RECOMMENDATIONS PARAMETERS

TABLE 13: RIGID PAVEMENT DESIGN RECOMMENDATIONS PARAMETERS

TABLE 14: COMPACTION REQUIREMENTS

TABLE 15: LIFT THICKNESS REQUIREMENTS FOR BACKFILL COMPACTION

FIGURES

FIGURE 1: MILITARY WORKING DOG FACILITY SITE LOCATION MAP

FIGURE 2: SOIL BORING & SOIL TESTING LOCATIONS ON CURRENT SITE LAYOUT5

FIGURE 3: SOIL BORING & SOIL TESTING LOCATIONS ON FUTURE SITE LAYOUT ..6

FIGURE 4: SEDIMENTATION SEQUENCE OF RYUKYU GROUP LAYERS

FIGURE 5: GEOLOGICAL MAP OF REGION SURFACE

FIGURE 6: JIS DESIGNATED ENGINEERED BASE & SUBBASE MATERIALS FOR

PAVEMENTS

Geotechnical Investigation Report vii Military Working Dog Facility

APPENDICES

A SOIL BORING LOGS

B SOIL PROFILES

C GEOTECHNICAL LABORATORY REPORTS

D FIELD WORK PHOTOGRAPHS

E PROJECT LOCATION LIQUEFACTION HAZARD MAP

F JIS STANDARD FOR PRECAST PRESTRESSED CONCRETE PILES (JIS A 5373)

G DAILY FIELD REPORTS / DAILY FIELD LOGS

H COPY OF A-E’S SUPPLEMENTAL STATEMENT OF WORK,

CONTRACT NO. W912HV-14-D-0002

I APPROVED WORK PLAN

J REVIEW COMMENTS

K ELECTRONIC FILE ATTACHMENT – PDF FORMAT FILE FOR GEOTECHNICAL

INVESTIGATION REPORT

NOTE:

1. ELECTRONIC FILE ATTACHMENT IS SENT TOGETHER WITH THIS

REPORT ON A SEPARATE CD WITH LABEL

Geotechnical Investigation Report viii Military Working Dog Facility

ACRONYMS AND ABBREVIATIONS

ASTM American Society for Testing and Materials AC Asphalt concrete B Minimum width of foundation bgs Below ground surface CBR California Bearing Ratio cm Centimeter DoD Department of Defense EM Engineering Manual FFE Finished Floor Elevation FY Fiscal Year H:V Horizontal : Vertical IBC International Building Code JCS Japan Construction Society JGD Japan Geodetic Datum JGS Japan Geotechnical Society JIS Japan Industrial Standards JLIT Japan Ministry of Land, Infrastructure, Transport and Tourism JRA Japan Road Association km Kilometer km2 Square kilometer KN Kilo Newton KN/m2 Kilo Newton per square meter KPa Kilopascals m Meter m2 Square meter MILCON Military Construction mm Millimeter MPa Mega pascal MN/m3 Mega Newton per cubic meter MSL Mean sea level MWD Military Working Dog (Facility) N Blow count of the Standard Penetration Test NACE National Association of Corrosion Engineers OSHA Occupational Safety & Health Administration OSK Otsuki Sekkei Co., Ltd.

PCC Portland cement concrete SPT Standard Penetration Test SSOW Supplemental Statement of Work tf Tons-Force UFC Unified Facilities Criteria UFGS Unified Facilities Guide Specifications US United States USACE United States Army Corps of Engineers

Geotechnical Investigation Report 1 Military Working Dog Facility

1.0 PURPOSE AND SCOPE

Otsuki Sekkei Co., Ltd. (OSK) was contracted by the Department of the Army, Albuquerque District Corps of Engineers to conduct geotechnical investigation and topographic survey services, and complete a Geotechnical Design Summary Report under Contract No. W912HV- 14-D-0002, FY16 Marine Corps MILCON Project Military Working Dog Facility (MWD) at Camp Hansen, Okinawa, Japan.

The purpose of this survey is to provide a Geotechnical Design Summary Report for the candidate site encompassing approximately 1.4 hectares of land and consisting of several operational base facilities. New facilities include but are not limited to a 520 square meter administrative facility, two indoor/outdoor kennel facilities, roadways, parking areas, typical landscaping and new utilities. The primary goal of the geotechnical site investigation is to develop foundation, retaining wall, slope embankment and pavement design recommendations.

2.0 PROJECT OVERVIEW

2.1 PROJECT TEAM

Work was conducted by the following project team:

Project Manager: Mr. Jumpei Hoshino (Otsuki Sekkei Co., Ltd) Geotechnical Engineer: Mr. Kazuaki Shindo (Shindo Soil Investigation, Ltd) Soils Laboratory & Drilling Support: Shindo Soil Investigation, Ltd.

Topographic and Coordinate Survey: Mr. Koji Chinen (Ryusoku Consultants, Inc.)

Field Civil Engineer / Report Support: Mr. Ken Bull (Environmental Science Corporation) Technical Quality Control: Mr. Jimmy Oshiro (Environmental Science Corporation)

2.2 SITE LOCATION

The project site for the new Military Working Dog Faculty is located east of Building 2494 in an unimproved forested lot in Camp Hansen, Okinawa, Japan (see Figure 1). The project site is bounded by the access roads to the CTA range to the west, the potable water storage tank area access road to the north and east, and the Okinawa expressway to the south. Project site elevations range from approximately 55 to 65m above sea level (ASM). A natural slope dissects the forested area running east to west approximately in the middle of the site. The project area covers an area of approximately 1.4 hectares of land.

Geotechnical Investigation Report 2 Military Working Dog Facility

Figure 1: Military Working Dog Facility Site Location Map

Geotechnical Investigation Report 3 Military Working Dog Facility

2.3 DESCRIPTION OF THE GEOTECHNICAL INVESTIGATION

The geotechnical investigation included 5 soil borings from 20 to 30 meters (m) depth conducted within the future facility footprint. Soils sampling and analysis to include soil engineering properties, uniaxial compression, modified Proctor, consolidation and California Bearing Ratio (CBR) testing. One of the five borings, B-3, was advanced to 30.5 m below ground surface (bgs) to observe deeper soils and to determine the seismic site class of the site. All borings were drilled until confirmation of consistent standard penetration test (SPT) N-values of 50+ which is considered a suitable bearing stratum for a deep foundation option for proposed facilities. In total, approximately 122 m of soil boring was conducted along with disturbed and undisturbed soil sampling of representative soil layers to be analyzed at Shindo Soils Investigation, Ltd., a certified local geotechnical laboratory, for basic engineering characteristics.

Non-core soil borings were performed using a 66-millimeter (mm) diameter single core tube bit and split spoon sampler with SPT performed once per meter of boring depth below ground surface. Disturbed samples were conducted using split spoon extracted samples and undisturbed samples were taken from a thin wall sampler at representative depths within site borings.

Representative soil samples were taken at key stratum and tested for soil parameters as described in Section 5.2 of this report. Soil boring logs and laboratory data are included in the report appendices.

The following describes the major work tasks associated with the contracted geotechnical investigation at the Site:

• Performed five (5) exploratory boring and soils investigation within the project site from 8 to 20 May 2015.

• Confirmed the depth to the competent bearing layer for the deep foundations option at the site and characterized all shallow, intermediate and deep soil layers at the site.

• Soil samples were taken at characteristic soil layers at representative boring locations as directed by the project geotechnical and field civil engineer. Soil samples were tested for the following characteristics by applicable American Society for Testing and Materials (ASTM) and Japan Industrial Standard (JIS) methodologies:

Classification of Soils (ASTM D 2487 / JGS 0051) Particle Size Analysis (JIS A 1204) Moisture Content (JIS A 1205) Liquid and Plastic Limit (JIS A 1203) One-dimensional Consolidation Test (JIS A 1217) Compaction Characteristics using Modified Proctor (JIS A 1210) Unconfined Compressive Strength Test for Cohesive Soils (JIS A 1216) California Bearing Ratio (CBR) (JIS A 1211, JGS 0721)

• Performed analysis of the field exploration and results of laboratory testing data to provide recommendations for allowable bearing pressures in support of foundation

Geotechnical Investigation Report 4 Military Working Dog Facility options for the various structures of the new Military Working Dog Facility.

• Provide retaining wall design parameters

• Reviewed as-built drawings and other pertinent data for the existing buildings in the vicinity of the Site.

• Provided flexible and rigid pavement design recommendations based on CBR sampling and analysis results in planned future paved areas.

• Provided construction considerations pertinent to earthwork, site grading and site drainage.

2.4 VERTICAL & HORIZONTAL COORDINATE SURVEY

A vertical and horizontal control point survey and topographical survey was conducted for this site in accordance with EM-1110-1-105 and project SSOW requirements. Topographic, control, and utility survey data was submitted in accordance with Tri-Services CAD Standards V 5.0 standards under a separate submittal to the USACE Albuquerque District. Project site control points were established in Japan Geodetic Datum (JGD) 2011 Zone 15 coordinate system and these control points were used to locate and coordinate all geotechnical investigation boring and soil test point locations.

Geotechnical Investigation Report 5 Military Working Dog Facility

Figure 2: Soil Boring & Soil Testing Locations on Current Site Layout

Geotechnical Investigation Report 6 Military Working Dog Facility

Figure 3: Soil Boring & Soil Testing Locations on Future Site Layout

Geotechnical Investigation Report 7 Military Working Dog Facility W912HV-14-D-0002 Camp Hansen, Okinawa , Japan

3.0 SITE GEOGRAPHICAL AND GEOLOGICAL FEATURES

3.1 GEOGRAPHICAL FEATURES

Okinawa is the largest island of the Ryukyus, a chain of hundreds of islands which lie in the subtropics just north of the Tropic of Cancer. The Ryukyus extend southwest in a span over 1,000 km long from Kyushu, the southernmost of Japan’s four main islands, to Taiwan. Okinawa island is located at 26°22’0” North 127°45’0” east and is approximately 103 kilometers (km) long, has an average width of 11.3 km, and covers an area of 1,176 square kilometers (km2).

The topography of the Ryukyus is characterized either by high islands consisting of uplifted ancient metamorphic, volcanic, or limestone rocks; or low lying islands consisting of limestone terrace platforms and more recent low lying coral beds. Karst topography shapes many of the features of the Ryukyus including caves, sinkholes, and plateaus.

The Okinawa main island can be divided into two distinct zones on the basis of geography and geology. The boundary between the geological zones is near the south end of a narrow isthmus within Uruma City. The northern geological zone, comprising about two-thirds of the islands, is a mountainous area with high relief and deep dissection. Scattered small villages, farms, and narrow roads are largely confined to coastal areas surrounding the central mountainous zone. The southern geological zone, consisting of approximately one-third of the island, is a less elevated and hilly country with moderate relief and only local deep dissection.

The project site is located at Camp Hansen, which is situated in central and eastern part of the Okinawa main island along the Pacific Ocean Coast as shown in the site location map, Figure 1.

Camp Hansen is situated in a relatively hilly region of the island. The elevation of the site ranges from roughly 55 to 65 m MSL within the project boundary and generally elevates from the south to north direction. A natural slope dissects the central forested area spanning east to west across the middle of the site.

3.2 GEOLOGICAL FEATURES

The principal stratum of the project site region is the Kayo Formation. Kayo formation slate of the Paleogene era is assumed to be the base rock stratum in this region, but is covered by Quaternary era layers which underlie the present terrain of the project investigation site.

The Geological Map of the region surround the project site is shown as Figure 5.

Chronological Table of Stratum

I) Kayo Formation = Eocene epoch of Paleogene era Consisting of Sandstone and Slate

II) Ryukyu Group = Pleistocene epoch of Quaternary era Consisting of Kunigami Gravel Layer

Geotechnical Investigation Report 8 Military Working Dog Facility

(1) Kayo Formation:

This layer forms the base rock of a wide region from the mid to northern area on the Okinawa Island. Sandstone is the main constituent of this formation; however insertions of slate constituents are also frequently confirmed within the formation. Phyllite, slate, schistose sandstone, and conglomerate sandstone inserts are also common.

Kayo Formation sandstone was confirmed at this project site by our soil boring investigation and this layer is considered to be the bedrock of the site. The confirmed portion of the sandstone layer was observed to have undergone considerable weathering.

(2) Ryukyu Group:

The Ryukyu Group is a generic name for sedimentary strata comprised of limy deposits called Ryukyu Limestone or non-limy deposits called Kunigami gravel, developed in Okinawa islands during the Quaternary of Pleistocene era. The sequence of strata is not established yet, because there is no clarified theory to explain complex variation facies of Ryukyu Group. It is still remaining subject of Okinawa geology. At the project site, we mainly confirmed strata of Kunigami Gravel during the investigation.

a. Kunigami Gravel Layer:

The Kunigami gravel layer contains a lot of facies of various sedimentary epochs. This layer is mainly formed by silt or clay, it interspersed pebbles and sand of quartz, phyllite, and sandstone origin. Those contained base rock materials was distributed by receiving remarkable weathering with reddish brown colorization. Kunigami Gravel Layer was confirmed by our soil boring investigation.

Figure 4: Sedimentation Sequence of Ryukyu Group Layers

A. Early Years of Sedimentation

B. Principal Years of Sedimentation

C. Present Years of Sedimentation (After protrusion)

Geotechnical Investigation Report 9 Military Working Dog Facility

Figure 5: Geological Map of Region Surface

Stratigraphy Key

Quaternary

Holocene

Pleistocene Ryukyu Group

Tertiary Miocene

Eocene Kayo Formation

Kunigami Group Mesozoic Cretaceous Nago

Formation

Coral Reef

Alluvium

Gravel

Limestone

Intrusive Rock

Sandstone

Phyllite & Sandstone

Green Rock

Fault

Camp Schwab

Project Site

Okinawa city

Chimu Gulf

Ishikawa city

Camp Hansen

Geotechnical Investigation Report 10 Military Working Dog Facility

4.0 SITE CONDITIONS

4.1 SUBSURFACE CONDITIONS

A general description of the subsurface conditions and various soil materials encountered during our field exploration are presented in this section.

4.1.1 Subsurface Profile of the Site

Site soils consist mainly of cohesive surface fill layers and intermediate soils of soft to stiff consistency followed by weathered sandstones. The weathered sandstone layer is considered to be the bedrock layer of the site displaying SPT N-values of ≥ 50 and is considered a suitable target stratum for a deep foundation option at the MWD facility.

Fill soils at the site are typically present up to roughly 5 m depth nearby the existing roadway structure and composed of a mixture of sandy silts and mixed with concrete and organic. Beyond the border regions of the existing forested area within the project site, top soils are found to be native soils rather than fill material.

Underlying the fill soil layer, interchanging layers of soft to very stiff natural cohesive strata and low to intermediate dense sand strata was observed of roughly 14 to 25 m conglomerate thickness.

Underneath the thick intermediate layer consisting of sandy silts, sandy clays, and silty sands with gravel is a highly densified weathered sandstone layer beginning at approximately 17 to 25m below ground surface (bgs) with equivalent elevation range of roughly 30-40 m MSL. This sandstone layer, and in some cases, a highly dense sandy silt layer directly above this layer, displays consistent SPT N-values of 50 or greater is considered a suitable candidate layer to support a deep foundation option for the future MWD facilities.

During the extraction of soil samples, no visual or olfactory indication of soil contamination was observed by investigative personnel. Distribution of the site subsurface soils can be referenced in soil profiles included in Appendix B of this report.

4.1.2 Groundwater

Groundwater was observed in all soil boring locations at depths varying between 12 to 16 m bgs at an equivalent elevation range of roughly 41 to 46m MSL. Based on the observations of groundwater levels at each of the soil borings, groundwater is thought to be below the depths of future excavations for shallow footings or for the construction of new site utilities. At the time of the investigation, no visual or olfactory indication of groundwater contamination was observed.

Groundwater elevation measurements for each boring location can be referenced in borings logs included in Appendix A of this report.

Fluctuations of groundwater level could occur due to change in seasons, variations in rainfall, and due to groundwater perching. For instance, during rainy seasons, groundwater can perch within the existing fill creating temporary groundwater control issues during construction. Therefore, care

Geotechnical Investigation Report 11 Military Working Dog Facility shall be taken during the construction phase for controlling ground water accumulation in trenches, excavations and pits.

4.1.3 Subsurface Variations

Based on results of the subsurface exploration and our experience, some variations in the continuity and nature of subsurface conditions within the project site should be anticipated. Due to uncertainties in the nature and depositional characteristics of the earth material at the site and the variable nature of fill material placement at the site, caution and engineering judgment must be exercised in interpolating or extrapolating subsurface conditions between or beyond the boring locations.

4.2 GEOLOGICAL SITE HAZARDS

Screening for geological site hazards, including susceptibility to liquefaction, slope failure, and settlement, was conducted at the MWD facility site.

4.2.1 Soil Liquefaction Potential

Generally, soils that are most susceptible to liquefaction are clean, loose, saturated, uniformly graded sands and/or coarse silts that lie below the groundwater table within a depth of 0 to 20 m bgs.

Based on the soil exploration conducted at the site, soils underneath the observed water table to a depth of roughly 20 m contain an intermingling of fine grained soils and fine sand soils consisting primarily of sandy silts, sandy clays, and silty sands. Other soil layers observed under the water table to a depth of 20m include also silty sands, silty sands with gravel, and weathered sandstone layers to a limited extent. All observed soil layers within the susceptible depth primarily present medium dense to very dense consistency ranging from 8 to >50 for SPT N-value.

The Japan Construction Society (JCS) states in “Recommendations for Design of Building Foundations [Kensetsu Kisou Kouzou Sekkei Shishin]” (JCA, 2001) procedures for recognizing and evaluating liquefaction susceptibility of sites. Alluvial soil layers from the existing ground level to 20 m depth that present fines content of less than 35% and containing sands and silts shall be evaluated further for possible liquefaction elements. Based on these criteria, soils at the MWD site are not considered susceptible to liquefaction.

In addition, liquefaction hazard maps published by the Okinawa Prefectural Government show that the project site is located in an area which is not considered to be prone to liquefaction. The liquefaction hazard map for the area surrounding the project site can be referenced in Appendix E of this report.

Geotechnical Investigation Report 12 Military Working Dog Facility

4.2.2 Potential Slope Instability and Settlement

The existing site is comprised mainly of naturally forested and sloped area bounded to the north and west by existing asphalt pavement roadways. Ground altitudes generally decrease from North to South and more gradually from West to East along the site. A topographic survey conducted by ESC in May 2015 indicates that the elevation difference between the south and north boundary of the site is approximately 56 to 61 m MSL while the elevation difference between the west and east boundary is approximately 55 to 58 m MSL.

Observations of existing site conditions do not indicate any potential issues of instability for existing natural slopes. Since there are currently no existing structures in the vicinity of the site under investigation, no ground settlement issues were observed at the site.

Based on preliminary design information obtained by the USACE Albuquerque District, the proposed future floor elevation (FFE) of the administrative building portion of the MWD facility is

58.7 m and 59.9 m MSL for the north and south floor slabs. The proposed FFE for Kennel 1 and Kennel 2 are 59.7 m and 58.5 m MSL, respectively. In order to achieve this future FFE, it is estimated that up to 3 m of fill at the Administration Building, up to 2.5 m of fill at Kennel 1, and up to 3 m of fill at Kennel 2 will be required to bring the existing ground level up to the proposed FFE. Retaining walls and earthen slopes will be constructed to interface with the existing topography of the areas surrounding the site. Anticipated settlements from the introduction of new fill and structure loads to the site will be discussed in further detail in Section 6.

Permanent slope gradients as a result of cut or fill operations shall be stable and have a maximum gradient of 2:1 (H:V). In addition, it is recommended that a bench of 1.5 m width be installed at every 5 m vertical interval.

4.3 SEISMIC SITE CLASS DESIGNATION

UFC 3-220-01 requires the verification of site class by performing at least one boring to a depth of

30.5 m (100 ft) or refusal (defined as N > 50 blows per meter) or other method determined by the building official. SPT N-value distribution criteria were used to determine the seismic site class designation for this project. Based on boring data and SPT values obtained during the investigation, site soils fit Site Class “E” criteria for seismic design considerations. The Site Class “E” determination is based on the state of SPT N-value distribution from ground to 30.5 m (100 ft) bgs as recorded at boring location B-3 and also verified at the other boring locations using available site data.

Geotechnical Investigation Report 13 Military Working Dog Facility

5.0 FIELD EFFORT

5.1 SOIL BORINGS AND STANDARD PENETRATION TESTING

Non-core soil borings and SPT per each meter drilled was conducted at the site from 8 to 20 May 2015 using a Model NS-75G Yanmar drilling rig equipped with 66-millimeter diameter tube bit and split spoon sampler. In total, 5 soil borings at were conducted at the site, each conducted to variable depths to confirm the depth of the appropriate bearing zone for a deep foundation option (i.e., pile foundation) for the MWD facility.

It was unknown at the time of survey whether shallow or deep foundations were appropriate for the proposed facility. For this reason, originally 6 planned bore holes to shallower depths underwent a field change to 5 deeper borings (to approximately 25 m bgs) so that the deep foundation option could be more clearly evaluated in the case that soils were determined to have insufficient bearing capacity or unacceptable predicted settlements under a shallow foundation scenario. The field change addressed by the observing site Civil Engineer and subsequently approved by the OSK project manager in liaison with the USACE Albuquerque Engineer District as a no-cost impact and technical improvement to the originally planned investigation effort, in accordance with the provisions of SSOW Section 4, Suggested Modifications.

Exploratory bore holes were placed in locations spanning the width of the proposed MWD building footprint and based on the information provided by the USACE SOW. Refer to Figures 2 and 3 and the following Table 1 that shows the boring locations, depths and their locational relation to the proposed MWD facility footprint.

All soil borings terminated at depths where a suitable target layer showing consistent SPT N-value of 50 or greater was encountered. The weathered sandstone layer is considered to be the bedrock of the site. Due to the consistency and density of this layer, it is considered to be the appropriate target stratum for the deep foundation option.

SPT N-values were evaluated along with soil testing data to provide foundation recommendations for the proposed MWD facility. Soil boring locations can be referenced in Figures 2 and 3 in Section 2.0.

In addition, 6 shallow excavations were conducted in order to obtain soil samples for Modified Proctor, uniaxial compression, CBR, and consolidation testing. Soil laboratory testing and results will be discussed in further detail in Section 5.2. Boring logs and soil laboratory test reports are included in the report appendices.

Geotechnical Investigation Report 14 Military Working Dog Facility

TABLE 1: SOIL BORINGS SUMMARY

Soil Boring

Top of borehole elevation (m MSL)

Depth of boring (m bgs) Purpose of soil boring

B-1 57.53 25.38

Determine the bearing layer and soil capacities for the new proposed MWD administrative building structure. A suitable bearing zone for a deep foundation option was located at approximately 22 m below FFE and consists of a very dense Silty sand (SM) with gravel and heavily weathered sandstone (SM) layers displaying SPT > 50.

B-2 58.14 20.15

Determine the bearing layer and soil capacities for the new proposed MWD administrative building structure. A suitable bearing zone for a deep foundation option was located at approximately 21 m below FFE and consists of a very dense heavily weathered sandstone (SM) layer displaying SP T> 50.

B-3 55.15 30.25

Determine bearing layer and soil capacities for the new proposed MWD Kennel 2 facility and to establish the seismic class of the site by evaluating the top 100 ft (30.5 m) of soils. Shallow foundations and new fill would bear on the existing silt (ML) top layer. A suitable bearing zone for a deep foundation option was located at approximately 26 m below FFE and consists of a very dense Silty sand (SM) and heavily weathered sandstone (SM) layers displaying SPT > 50.

B-4 60.30 25.27

Determine bearing layer and soil capacities for the new proposed MWD Kennel 1 facility. A suitable bearing zone for a deep foundation option was located at approximately 23 m below FFE and consists of a very dense weathered conglomerate rock (Sandy silt (ML) w/ gravel) layer displaying SPT > 50.

B-5 57.53 20.45

Determine bearing layer and soil capacities for the new proposed MWD Kennel 1 facility. A suitable bearing zone for a deep foundation option was located at approximately 21 m below FFE and consists of a very dense weathered sandstone (Silty sand (SM) w/ gravel) layer displaying SPT > 50.

Geotechnical Investigation Report 15 Military Working Dog Facility

5.2 SOILS LABORATORY TESTING

Thirty-eight (38) disturbed and nine (9) undisturbed soil samples were taken at representative soil layers at selected boring locations. In addition, an excavator and hand shovel were used to extract eight (8) test samples for Modified Proctor and CBR tests at test locations E-1 through E-6. Soils encountered at the site consisted mainly of cohesive fill soils overlying a mixture of intermediate soil layers of soft to high stiffness followed by dense weathered sandstones. Disturbed and undisturbed samples were extracted using the SPT split spoon sampler and a thin-wall sampler, respectively. Samples of typical layers were tested in the laboratory in accordance with relevant Japan Industrial Standard (JIS) and Japan Geotechnical Society (JGS) testing procedures, as follows:

Soils testing reports can be referenced in Appendix C and are also summarized in Tables 2 through 7 of this section.

TABLE 2: SOIL LABORATORY TESTING SUMMARY

Boring No. Depth (m) bgs

C la ss ifi ca tio n of

S oi ls (A

ST

M

D

Pa rt ic le

S iz e A na ly sis

(J

IS

A

4)

M oi st ur e C on te nt

A

5)

L iq ui d an d

Pl as tic L im it

(J

IS

A

3)

1D C on so lid at io n

T es t (J

IS

A

7) om pa ct io n by M od ifi ed

Pr oc te r

(J

IS

A

0)

U nc on fin ed C om pr es siv e St re ng th (J

IS

A

6)

BR

T es t (J

IS

A

1)

B-1 3.50 to 4.50 ○ ○ ○ ○ ○ ○

5.50 to 6.50 ○ ○ ○ ○ ○

8.00 to 9.00 ○ ○ ○ ○

12.00 to 13.00 ○ ○ ○ ○

14.00 to 15.00 ○ ○ ○ ○

19.00 to 20.00 ○ ○ ○ ○

22.00 to 23.00 ○ ○ ○ ○

B-2 6.00 to 7.00 ○ ○ ○ ○

9.00 to 10.00 ○ ○ ○ ○

12.00 to 13.00 ○ ○ ○ ○

14.00 to 15.00 ○ ○ ○ ○

17.00 to 18.00 ○ ○ ○ ○

B-3 1.50 to 2.50 ○ ○ ○ ○ ○ ○

3.50 to 4.50 ○ ○ ○ ○ ○ ○

6.00 to 7.00 ○ ○ ○ ○

9.00 to 10.00 ○ ○ ○ ○

12.00 to 13.00 ○ ○ ○ ○

15.00 to 16.00 ○ ○ ○ ○

Geotechnical Investigation Report 16 Military Working Dog Facility

Boring No. Depth (m) bgs

C la ss ifi ca tio n of

S oi ls (A

ST

M

D

Pa rt ic le

S iz e A na ly sis

A

4)

M oi st ur e C on te nt

A

5)

L iq ui d an d

Pl as tic L im it

(J

IS

A

3)

1D on so lid at io n

T es t (J

IS

A

7) om pa ct io n by M od ifi ed

Pr oc te r

(J

IS

A

0)

U nc on fin ed C om pr es siv e St re ng th (J

IS

A

6)

BR

T es t (J

IS

A

1)

18.00 to 19.00 ○ ○ ○ ○

23.00 to 24.00 ○ ○ ○ ○

25.00 to 26.00 ○ ○ ○ ○

28.00 to 29.00 ○ ○ ○ ○

B-4 6.00 to 7.00 ○ ○ ○ ○ ○ ○

8.00 to 9.00 ○ ○ ○ ○

12.00 to 13.00 ○ ○ ○ ○

16.00 to 17.00 ○ ○ ○ ○

19.00 to 20.00 ○ ○ ○ ○

B-5 3.00 to 4.00 ○ ○ ○ ○

6.00 to 7.00 ○ ○ ○ ○

9.00 to 10.00 ○ ○ ○ ○

13.00 to 14.00 ○ ○ ○ ○

18.00 to 19.00 ○ ○ ○ ○

E-1 1.00 to 1.50 ○ ○ ○ ○ ○ E-2 1.00 to 1.50 ○ ○ ○ ○ ○ E-3 1.00 to 1.50 ○ ○ ○ ○ ○ E-4 1.00 to 1.50 ○ ○ ○ ○ ○ E-5 1.00 to 1.50 ○ ○ ○ ○ ○ E-6 1.00 to 1.50 ○ ○ ○ ○ ○ ○

38 38 38 38 4 4 5 3 Notes: ○Indicates laboratory test has been conducted.

Geotechnical Investigation Report 17 Military Working Dog Facility

TABLE 3: SOIL PROPERTIES TEST RESULTS SUMMARY

Boring or Test Location /

Depth (m) bgs Soil Classification

Sieve Analysis Distribution (%) Atterberg Limits (%) Natural

Water Content

Gravel Sand Silt Clay

LL PL PI >4.75

mm

4.75- 0.0075 mm

0.075- 0.005 mm

<0.005 mm

B-1/ 3.50- 4.50 Sandy lean clay (CL) 2.4 37.6 29.5 30.5 37.9 24.8 13.1 23.9 B-1/ 5.50- 6.50 Fat clay (CH) 0.0 6.3 30.3 63.4 69.8 29.9 39.9 36.6 B-1/ 8.00- 9.00 Silty sand (SM) 2.7 49.9 28.3 19.1 32.5 23.8 8.7 22.7

B-1/ 12.00-13.00 Silty sand (SM) 0.2 50.4 37.8 11.6 28.3 22.6 5.7 25.6 B-1/ 14.00-15.00 Silty sand (SM) 0.2 61.0 25.1 13.7 27.0 21.8 5.2 24.3 B-1/ 19.00- 20.00 Silty sand w/ gravel (SM) 24.3 42.4 18.7 14.6 34.4 24.0 10.4 15.9 B-1/ 22.00- 23.00 Silty sand (SM) 4.1 60.7 20.2 15.0 26.9 21.6 5.3 15.8 B-2/ 6.00- 7.00 Sandy silt (ML) 1.5 47.2 32.7 18.6 30.7 23.1 7.6 19.1 B-2/ 9.00- 10.00 Sandy silt (ML) 0.0 49.7 34.1 16.2 26.9 21.0 5.9 18.1 B-2/ 12.00- 13.00 Silty sand (SM) 1.6 59.5 26.5 12.4 25.4 21.4 4.0 19.6 B-2/ 14.00- 15.00 Silty sand (SM) 11.1 55.4 20.3 13.2 32.5 23.4 9.1 12.7 B-2/ 17.00- 18.00 Silty sand (SM) 3.0 53.1 23.0 20.9 30.7 23.8 6.9 15.0 B-3/ 1.50- 2.50 Elastic silt (MH) 0.0 2.2 17.4 80.4 95.6 47.0 48.6 36.5 B-3/ 3.50- 4.50 Elastic silt (MH) 0.0 10.4 27.7 61.9 67.1 33.7 33.4 33.2 B-3/ 6.00- 7.00 Silty sand (SM) 11.6 49.3 21.0 18.1 33.5 24.1 9.4 22.5 B-3/ 9.00- 10.00 Clayey sand (SC) 4.4 48.5 19.3 27.8 47.4 24.7 22.7 39.6 B-3/ 12.00- 13.00 Sandy lean clay (CL) 1.2 37.2 29.8 31.8 38.2 24.0 14.2 41.0 B-3/ 15.00- 16.00 Sandy silt (ML) 0.8 47.5 34.7 17.0 29.3 23.3 6.0 11.8 B-3/ 18.00- 19.00 Silty sand (SM) 3.0 57.5 27.2 12.3 27.6 22.7 4.9 24.7 B-3/ 23.00- 24.00 Silty sand (SM) 11.1 56.0 19.1 13.8 25.4 21.5 3.9 13.2 B-3/ 25.00- 26.00 Silty sand (SM) 7.7 59.1 17.9 15.3 25.4 21.5 3.9 11.7 B-3/ 28.00- 29.00 Silty gravel w/ sand (GM) 53.4 35.5 6.5 4.6 27.7 22.0 5.7 19.9

B-4/ 6.00-7.00 Sandy silt (ML) 5.7 43.1 29.2 22.0 40.9 26.1 14.8 22.5 B-4/ 8.00- 9.00 Silty sand (SM) 2.2 50.2 28.5 19.1 36.7 25.2 11.5 b 20.8

B-4/ 12.00- 13.00 Sandy silt (ML) 0.4 48.1 35.6 15.9 27.3 22.4 4.9 17.2 B-4/ 16.00- 17.00 Silty sand (SM) 0.7 63.3 24.1 11.9 25.6 21.2 4.4 23.1 B-4/ 19.00- 20.00 Silty sand w/ gravel (SM) 16.9 56.7 13.7 12.7 36.3 24.8 11.5 18.1 B-5/ 3.00- 4.00 Sandy lean clay (CL) 1.8 36.9 25.2 36.1 46.4 24.3 22.1 24.9 B-5/ 6.00- 7.00 Sandy silt (ML) 3.6 45.8 32.4 18.2 33.5 23.9 9.6 19.7 B-5/ 9.00- 10.00 Silty sand (SM) 0.3 51.4 32.0 16.3 28.6 23.3 5.3 19.5 B-5/ 13.00- 14.00 Silty sand (SM) 1.1 56.6 26.8 15.5 31.2 24.1 7.1 22.3 B-5/ 18.00- 19.00 Silty sand w/ gravel (SM) 36.4 44.7 10.8 8.1 30.2 23.7 6.5 13.6

E-1/ 1.00-1.50 Sandy fat clay (CH) 9.6 32.6 21.9 35.9 50.2 25.9 24.3 19.2 E-2/ 1.00-1.50 Clayey sand (SC) 10.3 46.3 20.7 22.7 34.2 21.1 13.1 17.5 E-3/ 1.00-1.50 Clayey sand (SC) 4.0 48.3 17.8 29.9 43.9 23.0 20.9 19.3 E-4/ 1.00-1.50 Sandy silt (ML) 2.1 46.9 30.3 20.7 25.5 19.7 5.8 17.1 E-5/ 1.00-1.50 Sandy lean clay (CL) 2.0 36.7 29.9 31.4 33.5 19.0 14.5 14.4 E-6/ 1.00-1.50 Sandy lean clay (CL) 11.2 41.6 18.1 29.1 43.4 22.3 21.1 14.3

Geotechnical Investigation Report 18 Military Working Dog Facility

TABLE 4: MODIFIED PROCTOR / COMPACTION TESTING RESULTS

Test Location

Depth (m) bgs

Soil Classification

Compaction Natural Moisture Content

Liquid Limit, LL

Max Dry Density (g/cm3)

Optimum Moisture

Content (%) E-1 1.00-1.50 Sandy fat clay (CL) 1.842 14.0 19.2 50.2 E-2 1.00-1.50 Clayey sand (SC) 1.938 10.2 17.5 34.2 E-5 1.00-1.50 Sandy lean clay (CL) 1.927 12.3 14.4 33.5 E-6 1.00-1.50 Sandy lean clay (CL) 1.914 11.5 14.3 43.4

TABLE 5: 1D CONSOLIDATION AND UNIAXIAL COMPRESSION RESULTS

Boring No.

Depth (m) bgs

Soil Classification

Unconfined Compression Consolidation

Avg. Unconfined Compressive

Strength qu (kN/m2)

Avg Secant Modulus;

E50 (MN/m2)

Preconsoli-dation

Pressure Pc

(kN/m2)

Compression Index, Cc

B-1 3.50-4.50 Sandy lean clay (CL) 107.8 4.36 703.2 0.312 B-1 5.50-6.50 Fat clay (CH) 141.1 11.77 - - B-3 1.50-2.50 Elastic silt (MH)○ 101.5 10.77 1116.1 0.362 B-3 3.50-4.50 Elastic silt (MH) 168.7 13.83 958.8 0.395 B-4 6.00-7.00 Sandy silt (ML) 72.5 3.13 521.1 0.249

TABLE 6: DESIGN CBR RESULTS

Location

Depth (m) bgs

Soil Classification Design CBR (%)

E-3 1.00-1.50 Clayey Sand (SC) 1.9

E-4 1.00-1.50 Sandy Silt (ML) 1.0

E-6 1.00-1.50 Sandy lean clay (CL) 16.3

Geotechnical Investigation Report 19 Military Working Dog Facility

TABLE 7: CBR RESULTS OF LABORATORY COMPACTED SOILS AT OPT WC

Location

Depth

(m) bgs

Soil Classification CBR & Corrected CBR

Blows/ Layer Dry Density (g/cm3)

CBR & Corrected CBR (%)

E-6 @90% &

Wopt 1.00-1.50 Sandy lean clay (CL)

92 blows/ 3 Layer 1.911 27.9

7.5 42 blows/ 3 Layer 1.833 14.8

17 blows/ 3 Layer 1.645 2.4

E-6 @90% & Wopt + 2%

1.00-1.50 Sandy lean clay (CL)

92 blows/ 3 Layer 1.900 22.7

7.2 42 blows/ 3 Layer 1.840 16.2

17 blows/ 3 Layer 1.696 5.1

E-6 @100% &

Wopt 1.00-1.50 Sandy lean clay (CL)

92 blows/ 3 Layer 1.913 27.3

27.3 42 blows/ 3 Layer -

17 blows/ 3 Layer -

Geotechnical Investigation Report 20 Military Working Dog Facility

6.0 CONCLUSIONS & RECOMMENDATIONS

6.1 FOUNDATION RECOMMENDATIONS

6.1.1 Shallow Foundation Option

Recommended allowable bearing pressures for shallow foundations were calculated considering site soil layer characteristics and estimated new fill loads for each MWD facility based on the existing and future topography of the site. For Kennel 1 and Kennel 2, the allowable bearing pressure for shallow foundations (assuming continuous footings) is recommended to be 50 KN/m2 and 70 KN/m2, respectively. The width of footings should be considered by the designer to accommodate for the allowable bearing pressures presented in this section. An increment of 1/3 of this allowable bearing pressure can be considered for short-term loads such as earthquake and short-time wind loads. Shallow foundations are not recommended for the Administration Building for reasons later stated in Section 6.1.2.

The estimated total settlement of shallow foundations based on the above conditions, and using estimated loads provided by the USACE SOW (100 kN/m), is calculated in the order of 25 mm for

2.0 m wide continuous footings at Kennel 1. Settlement due to footing loads at Kennel 2 is estimated in the order of 30 mm for 2.0 m wide continuous footings. Lesser settlements are anticipated for continuous footings with width B of less than 2.0 m.

Due to the introduction of new fill loads to the site, differential settlement shall be controlled by allowing settlement to stabilize after filling operations occur. The Kennel 1 facility is estimated to undergo approximately 120 mm of settlement due to fill of up to 2.5m. It is anticipated that most settlement may occur rapidly, approximately within one week of the completion of fill operations.

However, at the Administration Building and Kennel 2, settlements due to long-term consolidation should also be considered due to underlying compressible soil layers. At the Administration Building and Kennel 2 facilities, settlements along the order of 250 mm are anticipated due to fill of up to 3 m. It is estimated that 50% of the settlements will occur within the first 30 days following completion of up to 3 m of fill placement. For this reason, it is recommended that in the case of the shallow foundation option, foundation structures and underground utilities should not be constructed within a 1-month period of the completion of filling and until settlements have been stabilized.

Resistance to lateral loading may be provided by friction acting at the base of shallow foundations, and by passive earth pressure acting on the buried portions of shallow foundations and grade beams.

A coefficient of friction of 0.55 can be considered acting between the spread footings and the new material fill layers and 0.30 for footings within existing cohesive soils. Passive earth pressure may be computed as an equivalent fluid having a density of 30 KN/m3.

Geotechnical Investigation Report 21 Military Working Dog Facility

6.1.2 Deep Foundation Option

Due to the softness of shallow at intermediate layers at the site, a deep foundation option was also analyzed for MWD facilities. For the purpose of this analysis and for pile length estimation purposes, each of the 5 soil borings was conducted to a depth where a suitable bearing zone for pile foundations was clearly observed.

Undocumented existing fill of 3 to 5 m thickness at the proposed Administration Building area may present significant settlement issues due to the uncertainty of fill soils quality and engineering behavior, inconsistency of material distribution and grade of compaction, and the existence of concrete and other organic debris observed within the layer during the site investigation. Removal or soil treatment of existing undocumented fill of this large thickness is cost prohibitive and therefore a pile foundation for the Administration Building is recommended. Due to the absence of suitable intermediate layers for friction piles, it is recommended that end-bearing piles be used. In addition, pile foundations will allow construction of foundation elements such as pile installation and pile caps to begin without delay, in contrast with shallow foundations which require more time for stabilization of settlements to occur.

The suitable bearing stratum for the site is the very dense weathered sandstone bedrock layer [Silty sand (SM)] displaying consistent SPT N-values of 50 blows. Assuming depth to pile caps are approximately 1 m below the FFE, the estimated pile lengths at the Administration Building are from 20 to 22m in total length (see Table 8 below).

TABLE 8: BEARING STRATUM ELEVATION & ESTIMATED PILE LENGTH

Boring No. / Location

Top of Borehole Elevation (m ASL)

Depth to Bearing Stratum (from ground surface at time of survey) (m)

Corresponding Elevation

(m) ASL

Esti…