(AH) Geotech Report 2021.pdf

Geotechnical Report

Naval Submarine Base - Motor Pool Storage Building Groton, Connecticut

Submitted to:

Symmes Main and McKee Associates, Inc.

1000 Massachusetts Avenue Cambridge, MA 01801

Submitted by:

GEI Consultants, Inc.

455 Winding Brook Drive, Suite 201 Glastonbury, CT 06033 860-368-5300

June 2 2021 Project No. 2004872

Daniel Granda, P.E.

Senior Engineer

Matthew Glunt, P.E.

Senior Geotechnical Engineer

Consulting

Engineers and

Scientists

G E O T E C H N I C A L R E P O R T N E W L O N D O N N A V A L S U B M A R I N E B A S E , M O T O R P O O L S T O R A G E B U I L D I N G G R O T O N , C O N N E C T I C U T J U N E 2 , 2 0 2 1 i

Table of Contents

1. Introduction 1

1.1 Project Summary 1

1.2 Scope of Services 1

1.3 Authorization 1

2. Site and Project Description 2

2.1 Site Description 2

2.2 Proposed Construction 2

3. Exploration Procedures 3

3.1 Test Borings 3

3.2 Geotechnical Laboratory Testing 3

4. Subsurface Conditions 5

4.1 Geologic Setting 5

4.2 Subsurface Conditions 5

4.3 Groundwater 6

5. Design Recommendations 7

5.1 General Suitability 7

5.2 Foundation Design 7

5.3 Floor Slab Design 8

5.4 Settlement 8

5.5 Building Code Seismic Provisions 8

6. Construction Considerations 10

6.1 Subgrade Preparation 10

6.2 Excavation and Dewatering 10

6.3 Freezing Conditions 11

7. Closure 12

7.1 Follow-on Services 12

7.2 Limitations 12

Figures

1 Site Location Map 2 Subsurface Investigation Location Map

Appendices

A CorBuilt Survey Report B Boring Logs C Geotechnical Laboratory Results D Photo Log E U.S. Seismic Design Map Reference

S T O R A G E B U I L D I N G

GEI Consultants, Inc.

ii

F American Water Works Association – Corrosion of Steel Pipe, 2005

S T O R A G E B U I L D I N G

1. Introduction

1.1 Project Summary

We understand the project referenced herein consists of a 20-foot by 40-foot pre-engineered building to be used for motor vehicle storage. This report was prepared to address foundation, site preparation, and soil management recommendations for the proposed development.

As discussed further in this report, the project site has a documented history of contamination, which will likely impact planning and design of the proposed structure.

The site has a history of contamination in this portion of the New London Submarine Base property and based on our review of Final Fourth Five-Year Review of Operable Units 1, 2, 3, 4, 5, 9 and 12, Naval Submarine Base New London, Groton, Connecticut, dated December 2016, the proposed storage building is within Site 23 which was a former tank farm.

1.2 Scope of Services

Our scope of work included the following tasks:

Information Review Project Management and Coordination Accident Prevention Plan (APP) Site Visit, Mark-out and Utility Clearance Soil Boring Geotechnical Laboratory Testing Environmental Laboratory Testing Geotechnical and Environmental Reports

A separate environmental report/summary letter will be provided with the results of the chemical testing and recommendations for contaminated soil and groundwater management.

1.3 Authorization

Our work was performed in general accordance with our proposal to Symmes, Maini and McKee Associates, Inc (SMMA) dated November 2, 2020 and our Standard Professional Services agreement executed November 2, 2020.

S T O R A G E B U I L D I N G

2. Site and Project Description

2.1 Site Description

The site is located at the Naval Submarine Base in Groton, Connecticut. As shown on Figure 1, the project area is located north of the check-in entrance, west of existing tanks, and is fully gated for access control.

The project area was scanned for utilities using geophysical methods prior to the start of drilling. The utilities plan shows underground buried utility lines (electricity, phone, sanitary sewer) as presented in Appendix A.

2.2 Proposed Construction

Conceptual drawings for the project were provided by SMMA. The proposed building will be located approximately 15 feet north of the existing propane tank concrete slab and have a footprint of 800 square feet (40-ft by 20-ft). The conceptual drawing provided by SMMA is presented as a base for Figure 2.

We understand the structure will be a pre-engineered metal storage building supported by reinforced concrete slab-on-grade suitable for vehicle loads and conventional shallow foundations.

S T O R A G E B U I L D I N G

3. Exploration Procedures

3.1 Test Borings

The test locations were laid out on the site using the provided conceptual plan. Approximate soil test boring locations relative to the site plan are shown on Figure 3.

New England Boring Contractors, Inc. (NEBC), under subcontract to GEI, conducted two soil test borings (B-1 and B-2), 20 feet and 60 feet north of the edge of the propane tank foundation, respectively (Figure 3). The soil test borings occurred on April 26, 2021. A GEI professional was present to oversee the drilling procedures and classify the soil and rock samples obtained. The purpose of this boring was to evaluate soil/rock conditions for the foundation recommendation and definition of the Seismic Site Class.

Both borings were advanced using hollow-stem augering procedures to 17 feet for B-1 and 18 feet for B-2 where the boring reached bedrock, after which each boring was advanced using rock coring procedures. Standard Penetration Tests (SPT) and split-spoon sampling were conducted continuously from ground surface to 17 feet and 18 feet in B-1 and B-2, respectively. The truck-mounted drilling rig used on the project was equipped with a 140-lb safety hammer. Boring B-1 was terminated at a depth of 20.5 feet, after proceeding through approximately 4.5 feet of presumed bedrock. Boring B-2 was terminated at a depth of 19.75 feet, after proceeding through approximately 2 feet of presumed bedrock.

No formal survey of boring location or ground elevation was conducted by GEI.

The boring logs for B-1 and B-2 are presented in Appendix B. After boring B-1 was completed, a monitoring well was installed. After boring B-2 was completed, it was backfilled with clean filter sands. All excess drilling spoils were placed in drums and delivered to Building 562 for storage and disposal by others.

3.2 Geotechnical Laboratory Testing

Laboratory testing was conducted on representative soil samples to confirm field identification of the soils, address corrosivity, and establish engineering characteristics for design. Tests performed by GeoTesting Express, under subcontract to GEI, included the following:

• Two (2) grain-size analyses with standard sieve set (ASTM D422)

• Two (2) AWWA Corrosion Suit tests.

S T O R A G E B U I L D I N G

The two (2) grain-size analyses samples were taken from test boring B-1 and B-2 at a depth range of 8 to 10 feet and 10 to 12 feet respectively. The test for B-1 showed the sample can be classified as a Silty sand with gravel. The test for B-2 showed the sample can be classified as a Silty sand.

Two soil samples were submitted for laboratory corrosion analysis, consisting of pH, Redox Potential, Resistivity and Total Sulfides. Table 1 presents the summary of all the laboratory tests results per test boring.

Table 1 – Corrosion Testing Results

Boring

ID

Depth (ft) Moisture pH Redox Potential

Resistivity Total Sulfide

B-1 2-8 Moist 7.1 188 3,000 Trace to positive

B-2 6-10 Moist 7.6 202 18,900 Trace to positive

The results of the both geotechnical and corrosion laboratory analyses are included in Appendix C. Corrosivity results from laboratory were solely based on pH, corrosion evaluation using the American Water Works Association – 2005 “Corrosion and Corrosion Control of Iron Pipe” literature, included in Appendix E, is summarized in Table 2.

Table 2 – AWWA 10-Point System for Corrosion of Steel Pipe

Boring ID pH Redox

Potential Resistivity Total

Sulfide Moisture Point Sum

Corrosive to Iron Pipe

B-1 1 0 0 3.5 1 5.5 No B-2 1 0 0 3.5 1 5.5 No

Table 2 presents the 10-point system presented on (AWWA, 2005). Values for pH, Redox Potential, Resistivity, total sulfide and moisture are assigned by using the laboratory results and field observation on moisture. The points assigned are then summed up on the “Point Sum) column to determine if the soil would be considered corrosive to an iron pipe.

Corrosiveness was assigned to Point Sum values equal or above 10. No potential corrosion for iron pipes was identified.

S T O R A G E B U I L D I N G

4. Subsurface Conditions

4.1 Geologic Setting

The Quaternary Geologic Map of Connecticut and Long Island Sound Basin (Rodway Stone et al., USGS, 1985) indicates that the site is underlain by artificial fill. Artificial fill was observed to be silty sands materials previously imported for construction of the site.

The Bedrock Geological Map of Connecticut (Rodgers, USGS, 1985) indicates that the site is underlain by the Mamacoke Formation. This bedrock material is generally described as light to dark gray, medium grained gneiss.

4.2 Subsurface Conditions

The generalized subsurface conditions at the site are described below, in order of increasing depth based on Boring B-1 and B-2. The subsurface conditions are known only at the exploration location and conditions in the area may differ significantly in areas not explored.

The nature and extent of variations between the sampling points will not become evident until construction.

Historic Fill – Historic fill soils were encountered from the ground surface to a depth of approximately 17 feet and 18 feet below ground surface in B-1 and B-2, respectively. This is consistent with our understanding of the site history and previous uses.

The recovered fill soil was relatively consistent, observed to be predominately brown to gray, fine to medium grained sand with silt and gravel. The silt was observed to be non-plastic and the gravel particles were up to ¼-inch in diameter. The proportion of non-plastic fines ranges from 5 to 15 percent. No deleterious materials (debris, large organics, etc.) were observed in the fill at the locations and depths investigated. As discussed in the associated environmental report, provided under separate cover, this fill is expected to be contaminated and special handling procedures will likely be required.

Uncorrected SPT N-values ranged from 7 to over 50 blows/foot, indicating loose to very dense conditions. In general, soil conditions were loose to medium dense to 6 feet in depth, medium dense to dense between 6 and 8 feet, and medium dense to very dense below 8 feet to refusal on rock.

Bedrock – Bedrock was cored from 17.0 feet to 20.5 feet in boring B-1 and 17.75 feet to

19.75 feet in boring B-2. The rock was observed to be a light to dark gray medium-grained metamorphic gneiss. The Rock-Quality Designation (RQD) was estimated to be 23 percent on the sample recovered in B-1.

S T O R A G E B U I L D I N G

4.3 Groundwater

Free groundwater was encountered at the time of drilling at depths 3.5 feet and 4.0 feet below ground surface in borings B-1 and B-2, respectively.

Groundwater levels are subject to seasonal and weather-related variations. Groundwater measurements made at different times and different locations may be significantly different than the measurements taken as part of this investigation.

S T O R A G E B U I L D I N G

5. Design Recommendations

5.1 General Suitability

In general, we believe the site is suitable for the intended construction. However, we highlight the following potential subsurface risks, which are addressed in more detail in the proceeding sections:

1. The site is underlain by historic fills of unknown origin and character. Though we believe, from the investigation results, that these materials can be sufficiently stabilized in place, some removal of debris-laden or otherwise unsuitable soils may be required.

2. Dewatering may be required within footing excavations.

5.2 Foundation Design

The proposed structure may be supported on conventional shallow foundations bearing on a subgrade consisting of historic fills similar to those encountered during the investigation.

To protect subgrades and facilitate dewatering, we recommend that a working platform consisting of 6 inches of crushed stone over geotextile fabric be placed on foundation subgrades soon after they are exposed. We also recommend that all footing subgrades be evaluated by a GEI representative prior to concrete placement.

The maximum allowable bearing pressures for the design of footings are listed in Table 1.

Table 1 – Allowable Bearing Pressure

Bearing Stratum Net Allowable Bearing Pressure

Historic Fill 1,500 lb/ft2

Minimum individual column footing (if used) and wall footing widths should be at least 36 and 18 inches, respectively. Exterior footings should bear at least 36 inches below the adjacent exterior grade for frost protection. Interior footings should be founded at least 18 inches below the bottom of the floor slab. The tops of all footings should be at least 6 inches below the bottom of the overlying floor slab.

S T O R A G E B U I L D I N G

5.3 Floor Slab Design

The slab-on-grade should bear on a 12-inch thick layer of crushed stone placed over a soil subgrade prepared in accordance with Section 6.1.

Design of the slab-on-grade may assume a modulus of subgrade reaction of 200 pounds per cubic inch (pci). We recommend that contraction joints be incorporated between the slab-on-grade and the columns and perimeter walls of the proposed building to accommodate minor differential settlements.

To limit moisture infiltration into any finished spaces, a 10-mil (min.) polyethylene vapor barrier should be placed beneath all moisture sensitive floor slabs. The vapor barrier should be sealed at the foundation walls, columns, and utility penetrations, and panels should be overlapped and joints sealed.

5.4 Settlement

Assuming the design and construction recommendations herein are followed, we estimate total settlement of the building will be less than 1 inch, and differential settlements will be less than ½ inch.

5.5 Building Code Seismic Provisions

We understand design of the storage building will be governed by the following Codes:

1. United Facilities Criteria (UFC) Dept. of Defense (DoD) Building Code, UFC 1-200- 01, with revisions through October 2019.

2. UFC DoD Structural Engineering, UFC 3-301-01, with revisions through October 2019.

3. UFC DoD Seismic Design of Buildings, UFC 3-310-04, with revisions through June 2016.

These codes generally align with the 2015 International Building Code. Based on the criteria of Building Code Section 1613.3.2 and the SPT N-values measured on site, we recommend the use of Site Class C for seismic design. The Site Class was used in conjunction with the seismic hazard (SS, S1) for this location to determine spectral design values, as follows

S T O R A G E B U I L D I N G

Table 2 - Seismic Design Values

UFC 3-301-01/UFC 3-310-04

Site Class C

SS 0.162 g

S1 0.058 g

SDS 0.130 g

SD1 0.066 g

PGAM 0.097 g Seismic Design Category

(Risk Category I, II, or III) B

Peak ground acceleration (PGAM) corresponds to the value corrected for site effects, as shown in ASCE 7-10. Seismic design factors given above correspond to Seismic Design Category A for Risk Category I, II, or III structures.

The soils below the foundation level at this site are not considered susceptible to liquefaction.

S T O R A G E B U I L D I N G

6. Construction Considerations

6.1 Subgrade Preparation

To prepare the site for grading operations, topsoil, organic matter, existing pavements, and other deleterious material should be stripped from the building and site improvement areas.

Soft, wet, loose, or otherwise un-suitable soils should be removed and replaced, or potentially re-compacted in-place.

After stripping and cutting and prior to placing fill or slab base materials, the resulting subgrade should be firm, stable, and unyielding. Stabilization, where required, may consist of removing unsuitable material and replacement with compacted Structural Fill, or where unsuitable soils are relatively thin, drying and compacting in place. Based on boring results we expect that historic fill soils will be suitable for support of the floor slab after proof-rolling as recommended below. However, we caution that removal and replacement of localized areas of fill with heavy deleterious material such as debris, organics, etc. may be required.

Soil subgrades should be proof-rolled with at least four (4) passes of a minimum 10-ton vibratory roller in open areas, or a 1-ton vibratory roller or large plate compactor, such as Wacker DPU4545 or equivalent, in trenches. Proof-rolling in close proximity to groundwater may need to be accomplished without vibratory action to reduce the potential for disturbance to the subgrade.

Footings should bear on historic fills absent deleterious materials. Bearing surfaces should be free of standing water, frost, and loose soil before placement of reinforcing steel and concrete. A working platform consisting of a 6-inch layer of compacted crushed stone over geotextile fabric is recommended to protect subgrades and facilitate dewatering.

We recommend that a GEI representative observe the final preparation of all slab and footing subgrades.

6.2 Excavation and Dewatering

Excavations will be primarily through moderate consistency fills. We expect that excavation through soils can be accomplished with conventional earthmoving equipment. Excavated soils should be assumed be contaminated, and thus must be handled in accordance with local regulatory standards, as addressed in the accompanying environmental report.

S T O R A G E B U I L D I N G

All excavations should be sloped or shored in accordance with the local, state, and federal regulations, including Occupational Safety and Health Agency (OSHA 29 CFR Part 1926) excavation trench safety standards.

Groundwater intrusion should be expected for footing and utility excavations deeper than about 3 feet below grade. Where encountered, excavation dewatering could likely be accomplished with filtered sumps and pumps located outside the footing or trench excavations. Dewatering effluent must be managed in accordance with all local regulatory standards. We would also recommend that the site be graded to route storm water runoff away from excavations.

6.3 Freezing Conditions

The soils at the site are frost susceptible. Therefore, if construction is performed during freezing weather, special precautions will be required to prevent the subgrade soils from freezing. Freezing of the soil beneath the foundation during construction may result in subsequent settlement of the structure.

All subgrades should be free of frost before placement of concrete. Frost-susceptible soils that have frozen should be removed and replaced with compacted Structural Fill. The footing and the soil adjacent to the footing should be insulated until they are backfilled. Soil placed as fill should be free of frost, as should the ground on which it is placed.

S T O R A G E B U I L D I N G

7. Closure

7.1 Follow-on Services

We recommend that GEI be kept on the project through the final design and construction phases for the following services:

Review geotechnical-related contractor submittals and assist in developing responses to questions from the contractor (i.e. RFI’s).

Provide periodic site visits during construction to view subgrades and consult on geotechnical-related issues that occur.

7.2 Limitations

This report was prepared for the use of the project team, exclusively. Our recommendations are based on the project information provided to us at the time of this report and may require modification if there are any changes in the nature, design, or location of the proposed building. We cannot accept responsibility for designs based on our recommendations unless we are engaged to review the final plans and specifications to determine whether any changes in the project affect the validity of our recommendations, and whether our recommendations have been properly implemented in the design.

Our professional services for this project have been performed in accordance with generally accepted engineering practices. No warranty, expressed or implied, is made.

S T O R A G E B U I L D I N G

Figures

SCALE: NTS

DRAWN BY: DG

CHECKED BY: --

DATE: 04/13/2021

FIGURE NO.

PROJECT NO: 2004872

NAVSUBASE NLON – Motor Pool Storage Building (General Location)

LEGEND

SOURCE: Google Maps

General Location of Project Site

CHECKED BY: --

DATE: 04/13/2021

FIGURE NO

PROJECT NO: 2004872

NAVSUBASE NLON – Motor Pool Storage Building

SOURCE: Proposed Motor Pool Storage Building Location provided by SMMA and NAVFAC

CHECKED BY: --

DATE: 04/13/2021

FIGURE NO

PROJECT NO: 2004872

NAVSUBASE NLON – Motor Pool Storage Building Test Boring Approximate Locations

LEGEND

Approximate locations for illustration purposes only. Concrete pad was used as a reference for distance on up and down direction, edge of existing pavement was used as a reference for right and left direction.

All borings location have wood stakes placed as of Friday April 9, 2021.

SOURCE: Proposed Motor Pool Storage Building Location provided by SMMA and NAVFAC

Approximate Boring Location

20’

60’

6’ B-2

B-1

S T O R A G E B U I L D I N G

Appendix A

Corbuilt Survey Report

Providing Ground Penetrating and Structural Radar Surveys

SURVEY REPORT

Customer: GEI Consultants

455 Winding Brook Dr, Suite 201, Glastonbury, CT 06033

Contact: Dan Granda

Job Location: NLSB

B455

Description: Supply Ground Penetrating Radar & Electromagnetic Induction Survey to locate and mark sub-surface utilities and structures to support soil boring / monitor well operations.

Results: Equipment: Geophysical Survey Systems, Inc. SIR-4000 Data Acquisition Unit with a 400 MHz antenna.

Radiodetection RD7100+ Electromagnetic Induction System

Technician conducted GPR & EMI survey within areas requested by customer to clear customer’s boring location. Technician marked sub-surface utilities with paint and flags (where applicable). Technician conducted follow-up walk through with on-site customer contact to convey the findings of the survey. Included with this report is a field sketch depicting the locations of the sub-surface utilities located with data collected via Trimble Geo7x HStar GPS unit.

Comments: Date of Survey: 4/9/21

A.J. Cholakis Date: 4/13/21

1101 Noank-Ledyard Rd, Unit 3, Mystic, CT 06355 Office (860) 415-9497 corbuilt@corbuilt.com

GEI – NLSB 4/9/21

36 Olive St. Waterford, CT 06385 Office (860) 415-9497 corbuilt@corbuilt.com

Terms and Conditions

CorBuilt LLC offers Ground Penetrating Radar and Electromagnetic Induction surveys for utility location and other subsurface items such as buried tanks or drums. Due to a variety of site conditions there can be limitations to the effectiveness of the equipment. It is widely acknowledged that these limitations can, on some occasions, result in a less than accurate survey. In some cases, either one or both systems may be completely ineffective.

This may result in relying on one system only or terminating the survey entirely. In good conditions, the two systems work best together to confirm the existence and accuracy of targets seen by both machines. CorBuilt

LLC will in all cases attempt to communicate any conditional limitations or problems with the survey. It is optimal for the client to plan a physical walk through of the site after the survey in order for the technician to explain all of the aspects of the markings, flags, and answer any questions about the conditions, etc. The collection, interpretation, and reporting of our data is relevant only to the job scope we have agreed to and does not entail any engineering, structural engineering, geological, or survey grade land surveying documentation.

Due to these limitations and possible inaccuracies CorBuilt LLC CANNOT AND WILL NOT GUARANTEE

100% ACCURACY OR THAT ALL UTILITIES OR STRUCTURES HAVE BEEN LOCATED AND

MARKED. The decision to proceed with saw cutting, drilling, or other construction or investigation procedures is entirely up to the client or site owner and the client or site owner assumes all risk.

CorBuilt LLC will not be responsible for the maintenance of the markings. How long the markings last is determined by weather, site conditions, traffic, etc., and CorBuilt LLC will not guarantee how long they will last.

CorBuilt LLC will be available to redo the markings or the entire survey, if necessary, at additional cost.

A survey by CorBuilt LLC does not constitute or replace a CBYD, Dig Safe, or any other law mandated local service call. CorBuilt LLC is not and will not be responsible for calling or scheduling these services. This responsibility is the clients or others.

Equipment and Limitations

Ground Penetrating Radar and Electromagnetic Induction are the primary tools used for both subsurface and concrete scanning surveys. Both systems are susceptible to site conditions that can result in false negatives or positives. In these cases, there is the possibility that a marked utility is not there, or an existing utility is not marked.

Ground Penetrating Radar

Site conditions that limit the GPR equipment range from soil types and conditions, water table and other moisture content issues, and surface conditions. The Radar equipment consists of an antenna mounted to the bottom of a stroller. The antenna needs to ride along in constant contact with the ground. Therefore, any rough terrain, like

36 Olive St. Waterford, CT 06385 Office (860) 415-9497 corbuilt@corbuilt.com small stumps from brush cutting, bushes, and any large debris can interfere with the survey. Water and other sources of moisture disburse the electromagnetic radar signal resulting in the inability to "see" through water tables or standing water. Some soil types like clay, iron rich soil layers, and others can also interfere with GPR.

Client agrees to stay no less than thirty-six inches (36”) away from CorBuilt markings unless otherwise specified.

Electromagnetic Induction (EMI)

Electromagnetic Induction is also susceptible to interference from many of the same conditions as GPR. In using

EMI, a transmitter is placed on the ground, and an electromagnetic signal is broadcast into the ground at a specific frequency. When this signal encounters a metal pipe or wire, that signal is carried along that target like an antenna.

The technician, with a wand built to receive that specific frequency, can follow and mark that target. There are many complex situations that can occur with this equipment that can result in inaccurate markings. In busy areas that have numerous targets, a larger target may emit a stronger signal resulting missing a smaller target nearby.

There are too many other difficulties with this technology to go into all of them here. Client agrees to stay no less than thirty-six inches (36”) away from CorBuilt markings unless otherwise specified.

Concrete Scanning

The issues with both GPR and EMI regarding concrete scanning generally involve reinforcement. The mixture of utilities and reinforcement in concrete and trying to isolate one from the other is extremely difficult. With

EMI, the broadcasting of the signal into the concrete means that all the metal reinforcement will carry the signal as well as the utilities. Even when inducing a signal directly to a pipe or wire, those utilities may have been grounded to the building steel or the reinforcement, and the signal will be carried erratically all over the place.

GPR cannot discern the difference between a pipe or conduit from reinforcement. Client agrees to stay no less than two (2”) away from CorBuilt markings unless otherwise specified.

GPS Mapping

CorBuilt LLC utility surveys include site markings only. Usually Paint, pin flags, or other agreed upon marking systems. CorBuilt LLC GPS services can be added to your contract at additional cost. We can provide KMZ

(Google Earth file) or CAD drawing. Our CAD drawings will be generated on a base drawing of your site supplied by you. CorBuilt LLC documentation files and drawings are informational only and are not professional survey grade materials. CorBuilt LLC is not a licensed land survey company, and the deliverables from our GPS services should not be construed as such.

S T O R A G E B U I L D I N G

Appendix B

Boring Logs

3-5-8-10

10-9-11-

8-2-3-4

10-12- 13-11

10-10- 14-17

5-3-6-11

45-26- 30-75

Surface grade flush mounted well

(NO

CON

CRETE).

Bentonite seal 1-3'

Solid

PVC

to grade.

Filter sands sur rounding screen and 2' above top of screen.

0.1"

Slotted

PVC

A rt ifi ci al F ill A rt ifi ci al

F ill

A rt ifi ci al F ill A rt ifi ci al

F ill 24/18

24/24

24/8

24/24

24/10

24/15

24/11

S1

S2

S3

S4

S5

S6

S7

S1: WIDELY GRADED SAND WITH SILT AND

GRAVEL (SW-SM); ~70% F-C sand (mostly F), ~20% F-C gravel, subround up to 1", ~10% non-plastic fines, brown to grayish brown, dry to damp, root fragments present, topsoil present 0-4".

S2A (0-9"): SILTY SAND WITH GRAVEL: ~60%

F-C sand, ~25% F-C gravel, angular up to 1", ~15% non-plastic fines, brown, dry to damp.

S2B (9-24"): NARROWLY GRADED SAND WITH

SILT (SP-SM): ~80% F-C sand (mostly F), ~10% F gravel, subround up to 0.25", ~10% non-plastic fines, brown to grayish brown, dry to damp.

S3: SILTY SAND (SM); ~ 75% F-C sand, ~15% non-plastic fines, ~10% F-M gravel subangular up to 0.5", gray, wet.

S4: SILTY SAND WITH GRAVEL(SM); ~ 45%

F-C sand, ~35% F gravel angular up to 0.25", ~20% non-plastic fines, peat at bottom of spoon shoe 7.9-8.0', gray to grayish brown, wet.

S5:SILTY SAND WITH GRAVEL (SM): ~45% F-C

sand, ~35% F gravel, angular up to 0.25", ~20% non-plastic fines, slight peat in spoon shoe, gray to grayish brown, wet.

S6: NARROWLY GRADED SAND (SP); ~90% F

sand, ~5% non-plastic fines, ~5% F-gravel, gray to grayish brown, wet.

S7: WIDELY GRADED GRAVEL WITH SILT AND

SAND (GW-GM); ~55% F-C gravel (fragmented cobble), angular up to 1.5", ~35% F-C sand, to to to to to to to

DRILLER NAME: Mike St. John

C = Core Sample S = Split Spoon Sample

U = Undisturbed Sample SC = Sonic Core DP = Direct Push Sample HSA = Hollow-Stem Auger

TOTAL DEPTH (ft): 20.5

RQD = Rock Quality Designation = Length of Sound Cores>4 in / Pen.,%

Qp = Pocket Penetrometer Strength

I.D./O.D. = Inside Diameter/Outside Diameter

B-1

WOR = Weight of Rods WOH = Weight of Hammer

DRILLING METHOD: Solid Stem Auger 0-10', Rotary and Wash 10-17'

LL = Liquid Limit

PID = Photoionization Detector

Sv = Pocket Torvane Shear Strength

PI = Plasticity Index

DRILLING INFORMATION

LOGGED BY: Patrick Blessing

AUGER I.D./O.D.: 3 inch / NA

NA, NM = Not Applicable, Not Measured

Blows per 6 in.: 140-lb hammer falling

30 inches to drive a 2-inch-O.D.

split spoon sampler.

RIG TYPE: Mobile Drill B-53

CORE BARREL TYPE: NX

Pen. = Penetration Length Rec. = Recovery Length

BORING INFORMATION

HAMMER TYPE: Safety Hammer

ABBREVIATIONS:

CASING I.D./O.D.: 4 inch/ NA

CORE BARREL I.D./O.D. 2 inch / NA

WATER LEVEL DEPTHS (ft): 3.5 4/26/2021 2:50 pm

DRILL ROD O.D.: inch

Blows per 6 in.

or RQD

Drilling Remarks/ Field Test Data

La ye r N am e

Well ConstructionPen./ Rec.

(in)

Sample Information

Sample No.

Depth (ft)

Elev.

(ft) Soil and Rock DescriptionDepth

(ft)

GEI PROJECT NUMBER: 2004872

PROJECT NAME: NAVFAC Motor Pool Building

CITY/STATE: Groton, Connecticut

NOTES:

DATE START/END: 4/26/2021 - 4/26/2021

DRILLING COMPANY: New England Boring Company

BORING

VERTICAL DATUM:

GROUND SURFACE EL. (ft): NM

LOCATION: Motor Pool Building

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21-17- 21-75

Slough backfill in bottom of borehole.

A rt ifi ci al F ill B ed ro ck

24/13

42/42

S8

C-1

~10% non-plastic to low plasticity fines, grayish brown to gray, wet.

S8: WIDELY GRADED SAND WITH SILT AND

GRAVEL (SW-SM); ~50% F-C sand, ~40% F-C gravel, angular up to 1", ~10% non-plastic fines, gray to grayish brown, wet.

At 16 ft to 17 ft, rotary drill used to probe bedrock depth due to increased density/ blow counts.

Competent bedrock encountered at 17 ft.

CORE: (C-1); 17-20.5'. PEN: 42", REC 42". RQD

23% TIME: (5.0, 5.5, 5.5 min/ft) BEDROCK TYPE: Zwm: Mamacoke Formation:

Inter-layered light to dark gray medium grained gneiss.

Terminated 3.5' into bedrock at a depth of 20.5'.

Monitoring well installed at location.

Installed Monitoring well.

to to

20.5

B-1

Blows per 6 in.

or RQD

Drilling Remarks/ Field Test Data

La ye r N am e

Well ConstructionPen./ Rec.

(in)

Sample Information

Sample No.

Depth (ft)

Elev.

(ft) Soil and Rock DescriptionDepth

(ft)

GEI PROJECT NUMBER: 2004872

PROJECT NAME: NAVFAC Motor Pool Building

CITY/STATE: Groton, Connecticut

NOTES:

DATE START/END: 4/26/2021 - 4/26/2021

DRILLING COMPANY: New England Boring Company

BORING

VERTICAL DATUM:

GROUND SURFACE EL. (ft): NM

LOCATION: Motor Pool Building

_G E

I W O

B U

R N

S T

D

-L O

C -L

A Y

E R

-W E

LL

N

A V

S U

B G

R O

T O

N M

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O R

P O

O L

B

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4-6-13-

10-7-4-4

20-8-8-6

3-14-20-

16-17- 16-15

8-8-6-10

5-5-6-8

A rt ifi ci al F ill A rt ifi ci al

F ill

A rt ifi ci al F ill A rt ifi ci al

F ill

A rt ifi ci al F ill A rt ifi ci al

F ill

24/16

24/10

24/11

24/18

24/12

24/16

24/18

S1

S2

S3

S4

S5

S6

S7

S1: WIDELY GRADED SAND WITH SILT AND

GRAVEL (SW-SM); ~70% F-C sand, ~20% F-C gravel angular up to 1", ~10% non-plastic fines, brown, dry to damp. Topsoil at 0-4"

S2: NARROWLY GRADED GRAVEL WITH

SAND (GP); ~60% C gravel (fragmented cobble), ~35% F-C sand, ~5% non-plastic fines, grayish brown to brown, dry to damp

S3: SILTY SAND WITH GRAVEL (SM): ~50%

F-C sand (mostly F), ~35% F-C gravel and fragmented cobble, subrounded up to 1", ~15% non-plastic fines, grayish brown to brown, damp to wet. Peat/ wood fragment in shoe spoon (5.75-6.0 ft).

S4: WIDELY GRADED SAND WITH SILT AND

GRAVEL: 70% F-C sand (mostly F), 20% F-C gravel, angular up to 1", 10% non-plastic fines, brown to grayish brown, moist to wet.

S5: NARROWLY GRADED SAND (SP); ~95% F

sand, ~5% non-plastic fines, grayish brown, moist to wet.

S6: NARROWLY GRADED SAND (SP); ~90% F

sand, ~5% non-plastic fines, ~5% F gravel, coarse sand from 9-12", brown to grayish brown, moist to wet.

S7: WIDELY GRADED SAND (SW): ~95% F-C

sand (mostly F), ~5% non-plastic fines, F-C sand from 6-9'', brown to orange brown (oxidized), wet.

to to to to to to to

DRILLER NAME: Mike St. John

C = Core Sample S = Split Spoon Sample

U = Undisturbed Sample SC = Sonic Core DP = Direct Push Sample HSA = Hollow-Stem Auger

TOTAL DEPTH (ft): 19.8

RQD = Rock Quality Designation = Length of Sound Cores>4 in / Pen.,%

Qp = Pocket Penetrometer Strength

I.D./O.D. = Inside Diameter/Outside Diameter

B-2

WOR = Weight of Rods WOH = Weight of Hammer

DRILLING METHOD: Solid Stem Auger 0-10', Rotary and Wash 10-19'

LL = Liquid Limit

PID = Photoionization Detector

Sv = Pocket Torvane Shear Strength

PI = Plasticity Index

DRILLING INFORMATION

LOGGED BY: Patrick Blessing

AUGER I.D./O.D.: 3 inch / NA

NA, NM = Not Applicable, Not Measured

Blows per 6 in.: 140-lb hammer falling

30 inches to drive a 2-inch-O.D.

split spoon sampler.

RIG TYPE: Mobile Drill B-53

CORE BARREL TYPE: NA

Pen. = Penetration Length Rec. = Recovery Length

BORING INFORMATION

HAMMER TYPE: Safety Hammer

ABBREVIATIONS:

CASING I.D./O.D.: 4 inch/ NA

CORE BARREL I.D./O.D. NA / NA

WATER LEVEL DEPTHS (ft): 4.0 4/26/2021 2:50 pm

DRILL ROD O.D.: inch

Blows per 6 in.

or RQD

Drilling Remarks/ Field Test Data

La ye r N am e

Well ConstructionPen./ Rec.

(in)

Sample Information

Sample No.

Depth (ft)

Elev.

(ft) Soil and Rock DescriptionDepth

(ft)

GEI PROJECT NUMBER: 2004872

PROJECT NAME: NAVFAC Motor Pool Building

CITY/STATE: Groton, Connecticut

NOTES:

DATE START/END: 4/26/2021 - 4/26/2021

DRILLING COMPANY: New England Boring Company

BORING

VERTICAL DATUM:

GROUND SURFACE EL. (ft): NM

LOCATION: Motor Pool Building

_G E

I W O

B U

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D

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C -L

A Y

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LL

N

A V

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18-13- 23-38

35-38- 38-75

A rt ifi ci al F ill A rt ifi ci al

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B ed ro ck

24/10

21/8

S8

S9

S8: WIDELY GRADED SAND WITH GRAVEL

(SW); ~70% F-C sand (mostly F), ~25% F-C gravel (fragmented cobble), angular up to 1", ~5% non-plastic fines, grayish brown, damp to wet.

S9: WIDELY GRADED SAND WITH SILT AND

GRAVEL: ~65% F-C sand, ~25% F-C gravel (fragmented cobble), angular up to 1.5", ~10% non-plastic fines, brown to black (fragmented weathered bedrock), wet.

At 17.75 ft, rotary drill used to probe bedrock depth due to increased density/ blow counts.

Weathered bedrock encountered at 19 ft.

Competent bedrock encountered at 19.75 ft, grind on weathered bedrock from 19.0-19.75ft.

BEDROCK TYPE: Zwm: Mamacoke Formation:

Inter-layered light to dark gray medium grained gneiss.

Terminated at the top of bedrock due to time constraints.

Backfilled with clean filter sands.

to to

17.8

B-2

Blows per 6 in.

or RQD

Drilling Remarks/ Field Test Data

La ye r N am e

Well ConstructionPen./ Rec.

(in)

Sample Information

Sample No.

Depth (ft)

Elev.

(ft) Soil and Rock DescriptionDepth

(ft)

GEI PROJECT NUMBER: 2004872

PROJECT NAME: NAVFAC Motor Pool Building

CITY/STATE: Groton, Connecticut

NOTES:

DATE START/END: 4/26/2021 - 4/26/2021

DRILLING COMPANY: New England Boring Company

BORING

VERTICAL DATUM:

GROUND SURFACE EL. (ft): NM

LOCATION: Motor Pool Building

_G E

I W O

B U

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S T

D

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C -L

A Y

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-W E

LL

N

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B

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S T O R A G E B U I L D I N G

Appendix C

Laboratory Results (Geotechnical and Corrosion)

Client: GEI Consultants, Inc.

Project: NAVSUBASE NLON-Motor Pool Stor Bldg Location: Groton, CT Project No: GTX-313602 Boring ID: B-1 Sample ID: S5 Depth : 8-10 ft

Sample Type: bag Test Date: 05/12/21 Test Id: 617947

Tested By: ckg Checked By: bfs

Test Comment: --- Visual Description: Moist, very dark grayish brown clayey sand with gravel Sample Comment: ---

Particle Size Analysis - ASTM D6913 printed 5/12/2021 12:56:57 PM

0.0010.010.11101001000

P er ce nt

F in er

Grain Size (mm)

0.

in

0.

% Cobble

% Gravel

18.8

% Sand

55.4

% Silt & Clay Size

25.8 Sieve Name Sieve Size, mm Percent Finer Spec. Percent Complies

0.75 in

0.5 in

0.375 in

#4

#10

#20

#40

#60

#100

#140

#200

19.00

12.50

9.50

4.75

2.00

0.85

0.42

0.25

0.15

0.11

0.075

Coefficients D =6.8245 mm85

D =0.8394 mm60

D =0.4363 mm50

D =0.1042 mm30

D =N/A15

D =N/A10

C =N/Au C =N/Ac

Classification

ASTM N/A

AASHTO Silty Gravel and Sand (A-2-4 (0))

Sample/Test Description Sand/Gravel Particle Shape : ANGULAR

Sand/Gravel Hardness : HARD

Client: GEI Consultants, Inc.

Project: NAVSUBASE NLON-Motor Pool Stor Bldg Location: Groton, CT Project No: GTX-313602 Boring ID: B-2 Sample ID: S6 Depth : 10-12 ft

Sample Type: bag Test Date: 05/12/21 Test Id: 617948

Tested By: ckg Checked By: bfs

Test Comment: --- Visual Description: Moist, light olive brown silty sand Sample Comment: ---

Particle Size Analysis - ASTM D6913 printed 5/12/2021 12:56:58 PM

0.0010.010.11101001000

P er ce nt

F in er

Grain Size (mm)

0.

% Cobble

% Gravel

2.7

% Sand

54.4

% Silt & Clay Size

42.9 Sieve Name Sieve Size, mm Percent Finer Spec. Percent Complies

0.75 in

0.5 in

0.375 in

#4

#10

#20

#40

#60

#100

#140

#200

19.00

12.50

9.50

4.75

2.00

0.85

0.42

0.25

0.15

0.11

0.075

Coefficients D =0.6856 mm85

D =0.1535 mm60

D =0.1012 mm50

D =N/A30

D =N/A15

D =N/A10

C =N/Au C =N/Ac

Classification

ASTM N/A

AASHTO Silty Soils (A-4 (0))

Sample/Test Description Sand/Gravel Particle Shape : ---

Sand/Gravel Hardness : ---

45 H Commerce Way Totowa, NJ 07512 Phone: 973-812-1818 http://www.terrasenselab.com/

05/16/2021 TerraSense Project Number: 7960-21006

Dan Granda Project Manager GEI Consultants 455 Winding Brook Drive, Suite 201 Glastonbury, CT 06033

Dear Mr. Granda:

Re: Laboratory Test Results for NAVSUBASE NLON-Motor Pool Storage

Building

The purpose of this letter is to present the results of the laboratory tests performed on the samples delivered to the TerraSense laboratory on 05/07/21. Testing was performed based on the assignment dated 05/07/21 by Dan Granda.

Test Results

Test results are reported on the accompanying test pages.

Test Comments

Testing was performed in general accordance to the ASTM or other methods as listed on the test pages. Deviations from the test standards are noted on these pages.

Limitations

Our professional services for this project have been performed in accordance with generally accepted engineering practices; no other warranty, expressed or implied, is made.

Sample Disposition

If we do not receive other instructions from you within thirty days, this material will be disposed of.

If you have any questions concerning the test results reported in this letter, please call us.

Sincerely, TerraSense, LLC.

Rosella Thomas Managing Member

Enclosure:

GEI Consultants #2004872-1.1 NAVSUBASE NLON-Motor Pool Storage Building

Summary of Corrosion Testing

SAMPLE ID RESISTIVITY TESTS CHEMICAL TESTS REMARKS

Boring Sample Depth As-Received @ Minimum Resistivity Awwa Appendix A

No. No. Test Water Resistivity Water Resistivity Redox Potential Sulfide

* Method Content Content pH Temperature R1 R2 R3 Average Response

(ft) (2) (%) (k - cm) (%) (k - cm) (pH units) (oC) (mV) (mV) (mV) (mV) (visual) B-1 S-2B+S-4 2-8 ASTM G57 25.0 3.0 30.2 3.0 7.1 20.7 188 185 191 188 trace to positive B-2 S-4+S-5 6-10 ASTM G57 19.6 18.9 19.6 18.9 7.6 21.2 208 195 202 202 trace to positive

* Tests performed on sample fraction finer than #8 sieve pH

ASTM G51

Prepared by: MT Reviewed by: RT Date: 5/16/2021

TerraSense, LLC 45H Commerce Way Totowa, NJ 07512

(973) 812-1818

Project No. 7960-21006 File: Corrosion1.xlsx

S T O R A G E B U I L D I N G

Appendix D

Photo Log

Project Photos - Geotechnical Report – New London Naval Submarine Base Motor Pool Storage Building Date: April 26, 2021 i | P a g e

Photo No. 1 – Soil Boring Activities, Boring B-1, April 26, 2021. _________________________________________ 1 Photo No. 2 – Artificial Fill Sample taking at B-1. _____________________________________________________ 2 Photo No. 3 – Open well installed at B-1 for water sampling. ___________________________________________ 3 Photo No. 4 – Soil Boring Activities, Boring B-2, April 26, 2021. _________________________________________ 4 Photo No. 5 – Artificial Fill Sample taking at B-2. _____________________________________________________ 5

1 | P a g e

Photo No. 1 – Soil Boring Activities, Boring B-1, April 26, 2021.

2 | P a g e

Photo No. 2 – Artificial Fill Sample taking at B-1.

3 | P a g e

Photo No. 3 – Open well installed at B-1 for water sampling.

4 | P a g e

Photo No. 4 – Soil Boring Activities, Boring B-2, April 26, 2021.

5 | P a g e

Photo No. 5 – Artificial Fill Sample taking at B-2.

S T O R A G E B U I L D I N G

Appendix E

U.S. Seismic Design Map Reference

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S T O R A G E B U I L D I N G

Appendix F

American Water Works Association – Corrosion of Steep Pipe, 2005