Volume_1_00_31_32.13_Geotechnical_Data_Report.pdf

McCook Reservoir Groundwater Monitoring Wells

Volume 1_00 31 32.13_Geotechnical_Data_Report

Chicagoland Underflow Plan (CUP) McCook Reservoir Main Tunnel System (MTS) Geotechnical Data Report (GDR)

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Chicagoland Underflow Plan (CUP) McCook Reservoir Main Tunnel System (MTS)

Geotechnical Data Report (GDR) Table of Contents

List of Acronyms ............................................................................................................................. i

1.0 Introduction ...................................................................................................................... 1-1

1.1 Purpose and Scope of the GDR ..................................................................................... 1-1

1.2 Project Description ........................................................................................................ 1-1

1.3 Elevation Datum and Horizontal Control ...................................................................... 1-3

1.4 Limitations .................................................................................................................... 1-3

2.0 Site Setting, Geology and Hydrogeology ........................................................................ 2-1

2.1 General .......................................................................................................................... 2-1

2.2 Regional Geology .......................................................................................................... 2-1

2.3 Project Site Geology...................................................................................................... 2-2

2.4 Geologic Formations ..................................................................................................... 2-3

2.4.1 Racine Formation ................................................................................................... 2-3

2.4.2 Sugar Run Formation ............................................................................................. 2-3

2.4.3 Joliet Formation ..................................................................................................... 2-3

2.4.4 Kankakee Formation .............................................................................................. 2-4

2.4.5 Elwood Formation ................................................................................................. 2-4

2.4.6 Wilhelmi Formation ............................................................................................... 2-4

2.4.7 Brainard Formation ................................................................................................ 2-4

2.4.8 Fort Atkinson Formation........................................................................................ 2-5

2.5 Regional Hydrogeology ................................................................................................ 2-5

3.0 Main Tunnel System Field Investigation Summary (AECOM 2008) ............................. 3-1

3.1 Field Investigation ......................................................................................................... 3-1

3.2 Laboratory Testing ........................................................................................................ 3-2

4.0 Available Geological and Geotechnical Data .................................................................. 4-1

4.1 Harza Engineering (1971-1976) .................................................................................... 4-7

4.2 Army Corps of Engineers (1991) .................................................................................. 4-7

4.3 Golder Associates (1992) .............................................................................................. 4-7

4.4 STS Consultants (1996) ................................................................................................ 4-8

4.5 Patrick Engineering (1998) ........................................................................................... 4-8

4.6 De Leuw, Cather & Company (1999) ........................................................................... 4-9

4.7 URS (2000) ................................................................................................................... 4-9

4.8 Other Investigations – TSC, SCS (1980-1990) ........................................................... 4-10

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5.0 Project Ground Conditions .............................................................................................. 5-1

5.1 Soil ................................................................................................................................ 5-5

5.1.1 Fill .......................................................................................................................... 5-6

5.1.2 Natural Soils........................................................................................................... 5-6

5.2 Rock .............................................................................................................................. 5-6

5.2.1 Racine Formation ................................................................................................... 5-6

5.2.2 Sugar Run Formation ............................................................................................. 5-7

5.2.3 Joliet Formation ..................................................................................................... 5-7

5.2.4 Kankakee Formation .............................................................................................. 5-7

5.2.5 Elwood Formation ................................................................................................. 5-8

5.2.6 Wilhelmi Formation ............................................................................................... 5-8

5.2.7 Maquoketa Formation ............................................................................................ 5-8

5.3 Rock Structure and Quality ......................................................................................... 5-10

5.3.1 Bedding ................................................................................................................ 5-10

5.3.2 Rock Joints ........................................................................................................... 5-10

5.3.3 Rock Quality Designation (RQD) ........................................................................ 5-11

5.3.4 In Situ Stresses ..................................................................................................... 5-11

5.4 Groundwater ................................................................................................................ 5-15

6.0 Previous Underground Experience in the Area ............................................................... 6-1

7.0 References ........................................................................................................................ 7-1

Tables

Table 4.1 Geotechnical Investigation Report Summary .............................................................. 4-2

Table 5.1 Drilling Program Summary ......................................................................................... 5-2

Table 5.2 Summary of Soil Engineering Properties (USACE, 2009) .......................................... 5-5

Table 5.3 Summary of Engineering Rock Properties .................................................................. 5-9

Table 5.4 Summary of Dilatometer Test Results (URS, 2001) ................................................. 5-14

Table 5.5 Groundwater Elevation Summary ............................................................................. 5-15

Table 6.1 Previous Underground Experience in the Area ........................................................... 6-1

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Appendices

Figure 1 Generalized Stratigraphic Column of Site Geology

Figure 2 Vicinity Map / Site Area Map

Figure 3 Exploratory Borehole Location Plan / Project Site Area Map

Figure 4 Geotechnical / Geological Profile

Appendix A Project Specific Lab Data Summary and Boring Logs

Appendix B Historical Boring Logs

Appendix C Historical Laboratory Data Summary

Appendix D Scatter Plots – Rock Engineering Properties

Appendix E Laboratory and In Situ testing Data (Raw)

Appendix F In Situ Stress Test Data

Appendix G Main Gate/Access Shaft Geologic Log and Groundwater Inflow Data

McCook Reservoir Groundwater Monitoring Wells i

List of Acronyms

ASTM American Society of Testing and Materials

BTS Brazilian tensile strength

CCD Chicago City Datum

CUP Chicagoland Underflow Plan

CSO combined sewer overflow

DDR Design Documentation Report

GBR Geotechnical Baseline Report

GDR Geotechnical Data Report gpm gallons per minute

HPU hydraulic power unit

ID inside diameter

LASMA Lawndale Avenue Solids Management Area

MGS Main Gate/Access Shaft

MTS Main Tunnel System

NAD 83 North American Datum of 1983 pcf pounds per cubic foot

PLI Point Load Index psi pounds per square inch

RQD Rock Quality Designation

SPT Standard penetration test

SWRP Stickney Water Reclamation Plant

TARP Tunnel and Reservoir Plan

TBM tunnel boring machinet

McCook Reservoir Groundwater Monitoring Wells ii tsf tons per square foot

UCS unconfined compressive strength

USACE United States Army Corps of Engineers

USCS Unified Soil Classification System

1-1

1.0 Introduction

1.1 Purpose and Scope of the GDR

The purpose of the Geotechnical Data Report (GDR) is to document field and laboratory studies conducted for the project, and to tabulate and summarize the factual geological and geotechnical data available from the project-specific investigation and available data from previously completed investigations and studies. The data will aid in identifying potential geotechnical hazards, determining ground conditions, characterizing soil and rock mass characteristics, establishing baseline conditions and evaluating methods of construction. The report includes data from twenty previous subsurface geotechnical and hydrogeological investigations between 1971 and 2009, within the McCook Reservoir Main Tunnel System (MTS) vicinity. These investigations comprised exploratory drilling and in-situ testing, followed by field and laboratory testing. This report summarizes the field data collected, presents the results of the laboratory tests performed, and reviews geological and historical literature pertaining to the site.

The investigation performed by AECOM (July 2008), for the McCook Reservoir MTS, was requested by the US Army Corps of Engineers (USACE), Chicago District in order to identify the geotechnical constraints associated with the design and construction of the proposed tunnel and shafts associated with the MTS.

The information presented in this Report consists of:

An overview of the project.

A description of the regional and project site geology.

A description of the Main Tunnel System laboratory and field tests.

A summary of the geotechnical investigations undertaken at the site.

A description of the Main Tunnel System ground conditions based upon the laboratory and field testing investigations.

A summary of previous underground construction experience near the project site.

Interpretation of the factual data presented in the GDR is included in a separate document referred to as the Geotechnical Baseline Report (GBR). This GDR applies solely to the McCook

Reservoir Main Tunnel System.

1.2 Project Description

Originally authorized in the Water Resources Development Act of 1999, the Chicago Underflow

Plan (CUP) McCook Reservoir Project is a key component of Chicago’s ongoing Tunnel and

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1-2

Reservoir Plan (TARP), providing approximately 10 billion gallons of additional combined sewer overflow (CSO) storage to the Metropolitan Water Reclamation District of Greater

Chicago’s (MWRDGC) network. To minimize flood damages (during periods of peak flow) to the City of Chicago and 36 surrounding suburban communities, the reservoir will store excess

CSO water from the TARP Mainstream and Des Plaines Deep Tunnel systems until the floodwater levels recede. This stored CSO will be pumped to Stickney Water Reclamation Plant

(SWRP) for treatment and appropriate discharge to the TARP network.

The McCook Reservoir MTS is a proposed 33 ft inside diameter (ID) tunnel that will connect the

Mainstream Tunnel and McCook Reservoir capable of conveying up to 30,000 cfs, and will be centrally located between the confines of the Des Plaines River and Chicago Sanitary and Ship

Canal. A plan view of the project location is shown in Figure 2.

The McCook Reservoir MTS contains the following main components:

Main Tunnel – An approximately 1,600 ft long, 33 ft ID tunnel connecting the Mainstream Tunnel and the McCook Reservoir, bifurcated for approximately 290 ft through the MGS.

Main Gate/Access Shaft (MGS) – An 88 ft ID, approximately 295 ft below grade circular shaft located near the midpoint of the Main Tunnel. The MGS is currently under construction under a separate contract (W912P6-09-C-0026).

Construction Shaft – Contractor Option – An optional, 25 ft ID, approximately 285 ft below grade shaft located approximately 300 ft downstream of the Main Tunnel/Mainstream Tunnel Connection.

Gates – Six rectangular steel wheel gates and the associated gate control structures located in the MGS. Each bifurcation of the Main Tunnel contains one main gate and two guard gates - one upstream and one downstream of the main gate. The gates and associated gate control structures are currently being manufactured under a separate contract (W912P6-08-C-0023)

Main Tunnel/Mainstream Tunnel Connection – Live connection of the Main Tunnel to the existing Mainstream Tunnel.

Main Tunnel/McCook Reservoir Connection – Portal connection of the Main Tunnel to the McCook Reservoir, including construction of an Energy Dissipation Structure.

Control Building – A surface facility located at the MGS that houses the gate operating controls, hydraulic power units (HPUs) and provides limited storage.

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1.3 Elevation Datum and Horizontal Control

For the purposes of this report, all boring locations previously surveyed have been converted to

State Plane NAD83 and Chicago City Datum, 1928 (CCD), to portray horizontal and vertical references.

1.4 Limitations

This report is part of the Contract Documents and has been prepared for the exclusive use of the

USACE as it relates to design and construction of the McCook Reservoir MTS. The report has been prepared in accordance with generally accepted engineering practice.

The Contractor must undertake his own independent review of the entire Contract Documents and other available data to arrive at decisions concerning planning the work, and the means, methods, techniques, sequences and procedures of construction for accomplishing the work.

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2.0 Site Setting, Geology and Hydrogeology

2.1 General

The site is located at the District's Lawndale Avenue Solids Management Area (LASMA) in

Willow Springs, Illinois. The site is within Lyons Township, T38N R12E in western Cook

County, and is bordered by the Stevenson Expressway (I-55) and the Des Plaines River to the northwest, the District operated sludge drying lagoons to the northeast, railroad tracks and the

McCook Reservoir to the southwest and the Chicago Sanitary Ship Canal to the southeast.

Access to the site is via West Lawndale Avenue. Immediately south of the site across Lawndale

Avenue is a building housing a natural gas facility.

Surface relief across the working site is minimal, ranging from approximately elevation 12.0

CCD at the McCook Reservoir to approximately El. 21.3 CCD near the connection with the

Mainstream Tunnel.

2.2 Regional Geology

The project area is covered by glacial drift underlain by about 4,000 ft of sedimentary rocks ranging in age from Cambrian to Silurian. The sedimentary rock is underlain by Precambrian granitic rock.

The Chicago region lies on the eastern flank the Kankakee Arch. The Kankakee Arch trends northwestward across Indiana and Illinois, connecting the Cincinnati Arch with the Wisconsin

Arch. The Silurian age bedrock strata dip gently eastward at about 15 ft per mile, and have an uneven top of rock surface dissected by Pleistocene age valleys and ridges. The Silurian bedrock is covered with a relatively thin mantle of glacial tills and valley fill sediments.

The bedrock surface is an undulating plain with valleys incised by glacial and pre-glacial erosion. These bedrock valleys are as much as 150 ft deep. The deeper, steep sided valleys were possibly incised during the retreat of the Illinoian continental glaciers, however there is no evidence, from the investigations performed at the McCook site, of an incised valley on or near the project site. It is estimated that 100 ft or more of the bedrock surface was eroded by glacial abrasion. The bedrock surface in the Chicago area is relatively fresh and unweathered. The uppermost part of the bedrock surface is generally fractured and the frequency of fracturing decreases with depth. Some fractures have been enlarged by solutioning and some vuggy porosity is present.

The sedimentary rocks of the Silurian age, the Maquoketa, and other strata overlying the

Precambrian, were deposited in generally shallow seas that advanced and retreated across the

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2-2 interior of North America some 300-500 million years ago. Due to large scale tectonic events along the eastern continental margin, occasional uplifts caused midwestern sediments to be raised above sea level, exposed to erosion, and buried under deposits from advancing seas. These uplifts produced stratigraphic breaks, or unconformities, in the sedimentary rock sequence.

Unconformities are often characterized by irregular contacts between formations. The uneven

Chicago bedrock topography is an erosional surface truncating the Kankakee Arch. The varying thicknesses of the Wilhelmi and Brainard Formations in the project area are due to the unconformity that separates the Silurian from Ordovician age strata.

The project site is located at the eastern end of a bedrock high that may be associated with one of these east/west trending folds which are superimposed on the regional dip of the Kankakee Arch.

These folds are broad and have amplitudes of about 200 ft over distances of several miles. The

Paleozoic strata dip 10 to 15 ft per mile eastward toward the Michigan basin and may also vary near reef structures. Locally the folded units may dip up to 100 ft per mile.

Two major fault zones are recognized in the Chicago region; the Sandwich Fault Zone and the

Des Plaines Disturbance. The Sandwich Fault Zone, located southwest of Joliet and approximately 30 miles southwest of the proposed Reservoir, consists of a northwest-southeast oriented fault with a vertical offset possibly more than 100 ft. The Des Plaines Disturbance, located northeast of O’Hare Field on the Des Plaines River (approximately 10 miles north of the proposed Reservoir), is an approximately circular area of internal faulting about 5.5 miles in diameter interpreted to be a impact feature. Numerous nearly vertical faults with vertical displacements of up to 600 ft expose older (Ordovician) rocks near the surface. Faulting within the Chicago area is rare, with the exception of those areas mentioned above. The few widely spaced faults in the project area are thought to have larger components of strike slip, rather than vertical offset, and generally trend northwest.

2.3 Project Site Geology

The site is located on a layer of surficial deposits comprising of fill material (presumably associated with ongoing dredging activities), poorly sorted recent alluvium, and lacustrine deposits from a prehistoric pleistocene lake. This lake was formed when glacial meltwater became impounded, reaching depths of up to 150 ft in places. As the glaciers retreated this lake eventually broke lose depositing several clay, silt, sand and some gravel horizons.

Underlying these deposits is a series of massive, relatively homogenous Silurian and late

Ordovician dolomites, including less prevalent interbedded shales formed during the early stages of diagenisis during this time. These rocks are a relatively uniform, approximately 300 ft thick, McCook Reservoir Groundwater Monitoring Wells

2-3 sequence across the site and incorporate the Racine Formation, Sugar Run Formation, Juliet

Formation, Kankakee Formation, Elwood Formation, and Wilhelmi Formation.

With the exception of the Des Plaines Disturbance (a probable meteorite impact zone) centered approximately 10 miles to the north, and some small, deep localized areas of possible seismic activity located to the south east, there are no significant fault traces noted within Cook County.

None of these faults are currently active and the seismic risk to the site is considered very low.

2.4 Geologic Formations

The geologic Formations (youngest to oldest) present at the project site are described below.

2.4.1 Racine Formation

The Racine Formation (Silurian System) consists of dolomite with zones of highly cherty strata in the middle and at the base of the formation.

During the Racine deposition, the Chicago area was occupied by a large complex of coral reef several miles in diameter. Three varieties, or facies, of the Racine are recognized as reef, reef-flank, and inter-reef facies. Some zones within the Racine display thin alternating layers of the reef and inter-reef facies within a short vertical distance, lenticular to continuous cherty horizons, and occasional solution pockets filled with clay and brecciated dolomite.

2.4.2 Sugar Run Formation

The Sugar Run Formation was named in 1973 by the Illinois State Geological Survey, six years after the initial subsurface exploration program for TARP and does not appear on early logs. It is designated as a well-bedded dolomite compromising what was formerly the basal 25 ft of the

Racine Formation. The unit is lithologically similar to many inter-reef deposits, and although readily observed in outcroppings in the Chicago area, it is difficult to identify in cores. The early logs were reviewed, and, where possible, the Sugar Run Formation was identified.

2.4.3 Joliet Formation

The Joliet formation is divided into the Romeo and Markgraf members. The Romeo Member is a persistent, fairly uniform, pure, white to cream, very dense, very fine grained dolomite about

14 ft in thickness, underlies the Sugar Run Formation, and grades downward into the Markgraf member. Where exposed, the Romeo Member is locally mottled pink, exhibiting poorly developed thick bedding. The Markgraf member is a widespread, distinctively light bluish gray dolomitic unit, underlying the Romeo Member. The Markgraf member consists of an upper zone which is fine grained, dense, containing a few, thin, clustered shale partings and soft, porous chert nodules; a middle argillaceous zone; and a silty lower zone in which closely spaced

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2-4 dolomitic shale laminae becomes increasingly common. The upper contact is defined as the uppermost cluster of shale partings.

2.4.4 Kankakee Formation

The Kankakee Formation generally has wavy beds of fine to medium grained, greenish gray, locally pinkish, dolomite layers, 1 to 3 in. thick. The bedding is often separated by numerous thin wavy partings of green shale. The upper contact is marked by thin laminae of bright green shale that occurs on a distinctive smooth, but deeply pitted surface.

2.4.5 Elwood Formation

The Elwood and Wilhelmi Formations are the oldest units of the Silurian System, formerly known collectively as the Edgewood formation. Their thickness varies widely because these were deposited on the underlying erosional surface developed on the top of the Maquoketa

Group (generally the Brainard Shale).

The Elwood is a light gray to gray and fine to medium grained dolomite slightly argillaceous in the upper 30 ft and often very cherty. The chert occurs in the form of interbeds and nodules to

0.3 ft thick at an average spacing of 1 ft and is white, soft and porous. The Elmwood upper contact is marked by a highly fossiliferous and vuggy zone below the bottom of the Kankakee

Formation within the highly cherty zone. The Elwood can be seen in the sump pit area of the

Vulcan Quarry, and has a tendency to form water seeps into the sump pit. The Elwood has demonstrated high hydraulic conductivities in borings throughout the project area, which may be due to secondary porosity caused by dissolution along the formation top.

2.4.6 Wilhelmi Formation

The lower portion of the Silurian Series is called the Wilhelmi Formation which is a slightly cherty dolomite unit underlain by an increasingly very argillaceous, non-cherty dolomite unit.

The upper portion of the Wilhelmi is known is known as the Birds Member. Within the Birds, chert nodules decrease in frequency and size with depth, but become harder. Conversely, the argillaceous content and frequency and thickness of shale and dolomitic shale partings increase with depth through the formation. The lowermost portion of the Wilhelmi is formed from reworked Brainard Formation sediments and is identified as the Schweizer Member. The

Schweizer consists of dolomitic shale with a basal layer of dolomitic siltstone, and containing brownish-black pebbles in a dolomitic shale matrix. Laminated, crinkled beds mark the base of the Schweizer.

2.4.7 Brainard Formation

The Brainard Formation of the Ordovician-Maquoketa Group is a dark greenish-gray, thin bedded, fossiliferous, silty claystone to shale with interbedded dolomite. The upper contact is

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2-5 sharp. As a result of pre-Wilhelmi erosion, it varies in thickness from 1 ft to 136 ft, depending on the configuration of the Brainard-Wilhelmi unconformity. In the project area, the formation is less than 10 ft thick and averages approximately 4.5 ft thick.

The Brainard has been known to cause serious problems of slaking in underground excavations in Northern Illinois. However, during excavation of the TARP tunnels and mainstream Pump

Station chambers, this problem was avoided by application of shotcrete shortly after excavation.

2.4.8 Fort Atkinson Formation

The Fort Atkinson is an inter-bedded green shale and dolomite. The dolomite is medium grained, hard, crystalline, light gray, and slightly argillaceous. The shale is moderately soft, green, and occurs as partings and bands to 0.1 ft thick.

Figure 1 (USACE, 2009) provides a generalized stratigraphic section of the site geology.

2.5 Regional Hydrogeology

Regionally, groundwater is encountered in the unconsolidated glacial deposits and in the underlying Silurian dolomite bedrock in the Chicago area. Although water supplies have been developed within these two upper hydrostratigraphic units, they are not considered major aquifers. The limited bedrock supply is primarily contained within the joints and bedding planes.

The Maquoketa shale forms a regional confining layer separating the Silurian dolomites from the underlying Ordovician units. Consequently, groundwater flow and quality within the upper dolomites (Silurian formations) differs from that found in the deeper sandstone formations.

The major aquifer/aquitard systems identified in the Chicago area include the following:

1. Glacial drift deposits (where sufficient deposit thickness and yields occur). Glacial deposits tend to be thin, with no significant water-bearing units in the project area.

2. Upper bedrock aquifers (Silurian dolomites). Generally not considered significant in the project area, with water limited to joints and bedding planes.

3. Upper Ordovician aquitards (Maquoketa Shale and Galena and Plattesville dolomites).

Not encountered within the tunnel horizon or shafts for this project.

4. Lower sandstone aquifers (Ordovician-St. Peter and Cambrian Ironton-Galesville sandstones). Not encountered within the tunnel horizon or shafts for this project.

Numerous open-pit rock quarries, such as the McCook Quarry, have been excavated into the

Silurian dolomite bedrock in the Chicago area. These quarries normally extend to the top of the

Maquoketa Shale, approximately 300 ft to 350 ft below the ground surface. Dewatering systems are required to keep the quarry bottom dry during operations. The dewatering operations have

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2-6 lowered water levels in surrounding bedrock and created a regional cone of depression within the dolomite. Groundwater flow within the upper bedrock aquifer is likely to have changed flow directions and hydraulic gradients over time, as existing quarries were excavated deeper and new quarries began operations in other areas (URS, 2001).

3-1

3.0 Main Tunnel System Field Investigation Summary (AECOM

2008)

In July 2008 the USACE, Chicago District contracted with AECOM to complete a geologic investigation for the proposed McCook Reservoir Main Tunnel System to supplement the existing available subsurface data described in Section 4.0. The geologic investigation was conducted to determine the geology, geotechnical and aquifer characteristics along the Main

Tunnel System alignment between the Mainstream Tunnel System and McCook Reservoir. A summary of the geotechnical investigation, from AECOM’s 2008 report is provided below.

Refer to Appendix A for the AECOM investigation boring logs.

3.1 Field Investigation

The three borings (LB-121-08, LB122-08 and LB-123-08) were completed by an AECOM drill crew using a D-25 truck-mounted rotary drill rig. A map of the approximate project site location, the soil boring locations, and geological/geotechnical profile are shown on Figures 2 through 4.

The borings were typically advanced using power auger and rotary wash methods through the overburden soil until the top of bedrock was reached. Soil samples were obtained using split-spoon sampling techniques in accordance with American Society of Testing and Materials

(ASTM) Standard D-1586. Samples were collected at 2.5 ft intervals until bedrock was reached.

Once the top of the bedrock had been reached, the rock was cored with an HQ sized bit in approximately 10 ft runs. Point load testing was performed in the field shortly after the cores were retrieved. The cores were labeled, placed into wooden core boxes, and photographed.

When boring LB-121-08, was drilled near the top of bedrock, several boulders were encountered that misaligned the casing; the hole location was offset approximately 5 ft, and the casing redrilled to approximately 2 ft into the bedrock.

At boring completion, packer testing was conducted using dual packers at approximate intervals of 20 ft. The boring at the MGS location (LB-121-08) was packer tested from 51 ft to 371 ft below ground surface, while borings LB-122-08 and LB-123-08 were packer tested between approximately 215 to 315 ft below the ground surface.

Following packer test completion, borehole geophysical logging was performed. AECOM subcontracted the geophysical evaluation to Geological Logging Systems, Bluefield, Virginia.

The geophysical evaluation was performed to characterize borehole temperature, water flow, gamma density, neutron density, and sonic measurements.

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3-2

After completion of the three main borings, two additional soil borings were drilled to collect undisturbed Shelby tube samples for laboratory testing. Three Shelby tubes were obtained;

however, at the lab it was found none of the recovered material was suitable for testing as the samples were either too soft, overly disturbed, or contained excessive granular material.

Once the geophysical evaluation was completed, the borings were tremie grouted to the ground surface using a portland cement grout, and the surface repaired with asphalt patching material.

The two soil borings drilled to collect Shelby tube samples were backfilled with bentonite chips, concreted and patched with asphalt.

Field logs and well installation diagrams were prepared as the drilling progressed, by an

AECOM field geologist, and are in general conformance with “The Standard Guide for Field

Logging Subsurface Exploration of Soil and Rock – ASTM D 5434”.

3.2 Laboratory Testing

In addition to point load testing performed in the field, laboratory tests were completed on selected rock and soil samples to characterize physical properties of soils and rock encountered in borings. The unconfined compressive strength (UCS) of selected cohesive soil samples was estimated using a calibrated penetrometer. The penetrometer values are shown on the individual boring logs. In conjunction with the laboratory testing program, the majority of the soil samples were classified on the basis of texture and plasticity in accordance with the AECOM Soil

Classification System. These descriptions and estimated group symbols are in general conformance with the Unified Soil Classification System (USCS), and are included on the soil boring logs. The following laboratory tests were performed on borings LB-121-08, LB-122-08, and LB-123-08, and the tabulated summary of results are presented in Appendix A.

Soil:

Particle Size Analysis

Specific Gravity

Moisture Content

Atterberg Limits

Rock:

Packer Testing

Unit Weight and Porosity

Brazilian Tensile Strength (BTS)

Unconfined Compressive Strength (UCS)

Direct Shear (pre-sawn)

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Direct Shear (existing)

Triaxial

Creep

Slake Durability

Swelling Strain

4-1

4.0 Available Geological and Geotechnical Data

Since the early 1970’s, twenty subsurface geotechnical and hydrogeological investigations have been performed with respect to construction of the proposed McCook Reservoir and

Main Tunnel System. The source of historical investigation information used in preparation of this GDR is the DDR for the Chicago Underflow Plan, Chicago, Illinois Vol. II of VIII dated November, 1999 (prepared by the USACE, Chicago District), and the Groundwater

Protection System Design Documentation Report for the Chicagoland Underflow Plan, Chicago, Illinois Vol. I dated August 2006 (prepared by the USACE, Chicago Illinois). The details of these investigations are summarized in Table 4.1 below and in the proceeding text.

Refer to Appendix B (CD provided in front sleeve of binder) for a summary of the included historical borings logs, location map, and the boring logs arranged by investigation title.

Refer to Appendix C for a summary of historical laboratory test results, and Appendix D for scatter plots of the rock engineering properties, Appendix E for the raw laboratory and in situ testing data, and Appendix F for the in situ stress test data.

4-2

Table 4.1 Geotechnical Investigation Report Summary

No. Report Name

Engineer /

Drilling

Contractor

Brazilian

Tensile

Strength (BTS)

Unconfined

Compressive

Strength

(UCS)

Unit Weight

(Wet Density)

Point Load

Strength Index

(PLI)

Rock Quality

Designation

(RQD)

Packer Test

Results

North Side

Rock Tunnel

Project

Harza

Engineering

Company

Yes Yes No No Yes No

Tunnel And

Reservoir Plan

Mainstream

System

Harza

Engineering

Company

Yes Yes No No Yes No

Mainstream

Tunnel System, Contract 73-

162-2H-Part 1

Harza

Engineering

Company

Yes Yes No No Yes No

Proposed

Railroad Spur to

LASMA

Testing Service

Corporation No No No No No No

LASMA-Water

Infiltration

Study

STS,

Northbrook-01 No No No No No No

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4-3

No. Report Name

Engineer /

Drilling

Contractor

Brazilian

Tensile

Strength (BTS)

Unconfined

Compressive

Strength

(UCS)

Unit Weight

(Wet Density)

Point Load

Strength Index

(PLI)

Rock Quality

Designation

(RQD)

Packer Test

Results

COE /

GRNDWTR /

IL

Golder

Associates No No No No Yes No

Golder

Associates No No No No Yes No

USACE /

McCook-2

Golder

Associates No No No No No Yes

MWRD @

LASMA

STS

Consultants Ltd.

Yes No No No Yes No

CUP-McCook

Reservoir

LASMA Site

Patrick

Engineering No Yes Yes Yes Yes No

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Engineer /

Drilling

Contractor

Brazilian

Tensile

Strength (BTS)

Unconfined

Compressive

Strength

(UCS)

Unit Weight

(Wet Density)

Point Load

Strength Index

(PLI)

Rock Quality

Designation

(RQD)

Packer Test

Results

CUP McCook

Reservoir -

5235.PO

Patrick Drilling

Inc., Boart

Longyear

Yes Yes Yes No Yes No

Patrick Drilling

Inc., Boart

Longyear

Yes Yes Yes No No No

Patrick Drilling

Inc., Boart

Longyear, &

Ruen

Yes Yes Yes No Yes No

CUP McCook

Reservoir, DES

Plaines Chicago

Sanitary and

Ship Canal Soil

Reports

STS

Consultants Ltd.

No No No No No No

McCook

Reservoir, IL, Design

Documentation

Report

USACE Yes Yes Yes Yes Yes No

McCook Reservoir Groundwater Monitoring Wells

4-5

Engineer /

Drilling

Contractor

Brazilian

Tensile

Strength (BTS)

Unconfined

Compressive

Strength

(UCS)

Unit Weight

(Wet Density)

Point Load

Strength Index

(PLI)

Rock Quality

Designation

(RQD)

Packer Test

Results

73STR. TARP

TUNNEL

RELOCATION

De Leuw, Cather &

Company/

Everest

Engineering Co.

No Yes No No Yes No

CUP McCook

Reservoir

STS

Consultants

Ltd./JEL/GBM

No No No No No Yes

McCook

Reservoir

Drilling and

Hydrogeologic

Characterization

STS

Consultants

Ltd./GBM

No No No No No Yes

McCook

Reservoir, Illinois, Deep

Bedrock

Boreholes

K&S Engineers, Inc.

No No No No No No

McCook Haul

Tunnels Design

Project

URS Yes No Yes Yes No No

McCook Reservoir Groundwater Monitoring Wells

4-6

Engineer /

Drilling

Contractor

Brazilian

Tensile

Strength (BTS)

Unconfined

Compressive

Strength

(UCS)

Unit Weight

(Wet Density)

Point Load

Strength Index

(PLI)

Rock Quality

Designation

(RQD)

Packer Test

Results

McCook

Reservoir

Overburden

Investigation -

Contract 73-

SEECO

Consultants, Inc.

No No No No No No

McCook CUP;

LASMA,

McCook, Illinois

K&S Engineers, Inc.

No No No No No No

McCook

Reservoir Main

Tunnel System

AECOM Yes Yes Yes Yes Yes Yes

McCook Reservoir Groundwater Monitoring Wells

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4.1 Harza Engineering (1971-1976)

The Hodgkins Pump Station, located between the Des Plaines River and the Vulcan Quarry, was investigated by Harza Engineering under contract to the MWRDGC in 1976, the Mainstream

Tunnel System, Contract 73-162-2H-Part 1. This investigation consisted of soil and rock borings necessary for the design of the buildings, shafts and chambers, and tunnels located at the pump station. The study conducted UCS tests (Appendix E) as part of the investigation. In addition, borings relevant to the project area have been referenced from work performed in 1972 for the design of the tunnel systems under the North Side Rock Tunnel Project contract. Harza conducted BTS, UCS, and RQD tests under this contract. Harza also conducted investigations

BTS and RQD tests between 1974 and 1975 for the Tunnel and Reservoir Plan Mainstream

System project (Appendix B). Harza performed a hydrogeologic investigation in October 1983, for the MWRDGC and the purpose of the investigation was to determine the hydraulic properties of various rock strata in the project area. Refer to Appendix C for a summary of the laboratory test data, Appendix D for histograms of the rock engineering properties and Appendix E for the raw laboratory data. See report numbers 1, 2, and 3 in Tables 4.1 and 5.1 for additional information.

4.2 Army Corps of Engineers (1991)

The U.S. Army Corps of Engineers, Nashville District, in November 1991 performed a subsurface investigation to determine the engineering properties of rock in the areas of the proposed underground and hydraulic structures and the investigations were contracted to Golder

Associates under the COE/GRNDWTR/IL contract. The boring locations for this investigation were based on the reservoir being at the Vulcan Quarry. The U.S. Army Corps of Engineers, Ohio River Division Laboratory, performed laboratory testing of the rock samples collected.

Geophysical logging of the boreholes was performed by the U.S. Department of the Interior, Bureau of Reclamation, to aid the subsurface characterization including discontinuities and help define the stratigraphy of the project area. No independent report was produced. Refer to

Appendix C for a summary of the laboratory test data, Appendix D for histograms of the rock engineering properties and Appendix E for the raw laboratory data. See report number 12 in

Tables 4.1 and 5.1 for additional information.

4.3 Golder Associates (1992)

Golder Associates, Naperville, Illinois, was contracted by the Chicago District in September

1992 to perform an additional hydrogeologic investigation under the USACE/McCook-2 contract. This investigation included installation of piezometers, performing packer testing, slug and pressure testing, laboratory tests of rock permeability, measurement of static groundwater

McCook Reservoir Groundwater Monitoring Wells

4-8 levels, and conducting four groundwater pump tests. A summary of the results from the packer tests for this investigation are presented in Appendix C, histograms of the rock engineering properties in Appendix D, and the raw laboratory data in Appendix E. In addition, water quality samples were collected to provide baseline data on the groundwater chemistry. See report numbers 6 and 7 in Tables 4.1 and 5.1 for additional information.

4.4 STS Consultants (1996)

STS Consultants performed an investigation at the LASMA site under the MWRDGC at

LASMA contract to the MWRDGC, following the change in the reservoir location. The investigation consisted of five borings to determine the quality of the rock for marketability and was performed in 1996. A summary of the results for the BTS and RQD tests performed are presented in Appendix C, histograms of the rock engineering properties in Appendix D, and the raw laboratory data in Appendix E. In conjunction with this investigation, Patrick Engineering tested select rock samples for engineering properties under contract to the Chicago District.

STS Consultants performed an evaluation of the Des Plaines River and Sanitary Ship Canal

Waterways located adjacent to the LASMA reservoir site under the CUP McCook Reservoir and

McCook Reservoir Drilling and Hydrogeologic Characterization contracts. The report from this investigation was submitted to the USACE in 2000. The information obtained from the borings was used to determine the depth of the water bodies and to evaluate the potential hydraulic connections between the surface water body and the bed rock aquifer. The investigation included

RQD, BTS, unit weight (wet density), point load PLI, and UCS tests. Refer to Appendix C for a summary of the laboratory test data, Appendix D for histograms of the rock engineering properties and Appendix E for the raw laboratory data. See report numbers 11, 14, and 15 in

Tables 4.1 and 5.1 for additional information.

4.5 Patrick Engineering (1998)

Patrick Engineering also performed an investigation at the LASMA site. This investigation was performed in 1998 and consisted of 11 borings, 5 vertical and 6 angled. Conventional and hydrophysical borehole geophysics were performed as part of this program along with extensive laboratory rock testing. A summary of the results for the RQD, unit weight (wet density), and

UCS tests conducted are presented in Appendix C, histograms of the rock engineering properties in Appendix D, and the raw laboratory data in Appendix E. The information was submitted to the Chicago district in a report entitled, “Report of Geologic Investigation for the CUP-McCook reservoir LASMA Site”.

McCook Reservoir Groundwater Monitoring Wells

4-9

A subsequent investigation was performed by Patrick engineering in 1998-1999 under the CUP

McCook Reservoir - 5235.PO contract to further investigate the overburden soils at the LASMA site. This work included sampling and testing soil samples collected and the installation of 11 observation wells in the overburden. In addition, a total of four test pits were excavated in lagoons 3 and 10 of the LASMA facility to evaluate the ability to dig the overburden soils. The information was used to determine the stability of the excavated overburden slopes and recommend methods to control the flow of groundwater through the slopes. This was submitted to the Chicago District in a report entitled, “Report of Overburden Stability Investigation for the

CUP-McCook Reservoir Site”. A summary of the results from the BTS, unit weight (wet density), and UCS tests conducted are presented in Appendix C, histograms of the rock engineering properties in Appendix D, and the raw laboratory data in Appendix E. See report numbers 9 and 10 in Tables 4.1 and 5.1 for additional information.

4.6 De Leuw, Cather & Company (1999)

The MWRDGC contracted with DeLeuw, Cather & Company for the design needed to relocate a

14 ft diameter tunnel that crosses the LASMA Site under the 73rd Street. TARP Tunnel

Relocation contract. As part of this work, 3 borings were drilled by Everest Engineering Co.

along the alignment on the south bank of the Chicago Sanitary and Ship Canal. The information gathered from this investigation is documented in a report entitled, “Geotechnical Investigation –

73rd Street TARP Tunnel Relocation (Contract No. 97-156-2H)”. A summary of the results from the RQD and UCS tests conducted are presented in Appendix C, histograms of the rock engineering properties in Appendix D, and the raw laboratory data in Appendix E. See report number 13 in Tables 4.1 and 5.1 for additional information.

4.7 URS (2000)

The MWRDGC contracted with URS Corporation in 2000 for the design and construction of two tunnels and associated portals and shafts needed for facilitating open pit mining to develop a flood storage reservoir for LASMA. As part of this work, 2 borings were drilled to perform in-situ testing, laboratory testing, and geologic mapping. The information gathered from this investigation is documented in a report entitled, “McCook Haul Tunnels Design Project, McCook, Illinois”. A summary of the results from the BTS, unit weight (wet density), and PLI tests conducted are presented in Appendix C, histograms of the rock engineering properties in

Appendix D, and the raw laboratory data in Appendix E. See report number 17 in Tables 4.1 and

5.1 for additional information.

McCook Reservoir Groundwater Monitoring Wells

4-10

4.8 Other Investigations – TSC, SCS (1980-1990)

Additional overburden investigations were performed at the LASMA site at various times by the

MWRDGC. These included a series of investigations by TSC in 1980 and 1983 to analyze the stability of the berm along the Chicago Sanitary and Ship canal under the Proposed Railroad

Spur to LASMA contract; an investigation by STS in 1990 to develop a design to control exfiltration from the lagoons under the LASMA-Water Infiltration Study contract; investigations by K&S Engineering in 2000 under the McCook Reservoir, Illinois, Deep Bedrock Boreholes contract and between 2006 and 2008 under the McCook CUP; LASMA, McCook, Illinois contract; and investigations performed by SEECO between 2000 and 2001 under the McCook

Reservoir Overburden Investigation - Contract 73-161-CH contract. Refer to Appendix C for a summary of the laboratory test data, Appendix D for histograms of the rock engineering properties and Appendix E for the raw laboratory data. See report numbers 4, 16, 18, and 19 in

Tables 4.1 and 5.1 for additional information.

5-1

5.0 Project Ground Conditions

For purposes of defining stratigraphy at the shafts and along the tunnel horizon the

Geotechnical/Geological Profile (Figure 3) was developed using eight (8) borings selected within 650 ft of the shafts and tunnel with legible boring logs. These are:

Borings LB 121-08, LB 122-08, and LB-123-08 (AECOM), 156-B1 (Everest), LB

101-98 (Patrick), LB 106-98 (Huen), LB 101-98, OW-1 (STS). Refer to Appendix A.

The subsurface conditions encountered during the investigation for this project were generally consistent with the data collected from previous investigations, and from published geological information. A statistical analysis of the entire geotechnical data set (1971 through

2008) yielded similar ranges and averages and the geotechnical and geological parameters, including in situ stresses, have been developed based upon the entire geological data set available in the project vicinity (Appendices A, C, and E). Refer to Table 5.1 for a listing of the boring logs considered for this report. Engineering properties from this data set were then assembled, grouped by rock formation, and presented in Table 5.3.

A description of the subsurface conditions is provided and should be read in conjunction with the exploratory borehole logs (refer to Appendices A and B), boring location plan (Figure 2), geological/geotechnical profile (Figure 3), and laboratory and in situ testing data (refer to

Appendix E).

5-2

Table 5.1 Drilling Program Summary

No. Report Name Engineer Drilling Contractor Boring Date No. of

Borings Soil/Rock

1 North Side Rock Tunnel Project - Harza Engineering Company 1971 3 soil & rock

Tunnel And Reservoir Plan

Mainstream System

- Harza Engineering Company 1974 - 1975 9 soil & rock

Mainstream Tunnel System, Contract

73-162-2H-Part 1

- Harza Engineering Company 1976 22 soil & rock

Proposed Railroad Spur to

L.A.S.M.A

- Testing Service Corporation 1981 & 1983 25 soil only (top of rock)

5 LASMA-Water Infiltration Study - STS, Northbrook-01 1990 17 soil only

(top of rock)

6 COE/GRNDWTR/IL

- Golder Associates 1992 5 soil only

(top of rock)

- Golder Associates 1992 18 soil & rock

7 USACE/McCook-2 - Golder Associates 1993 8 soil & rock

McCook Reservoir Groundwater Monitoring Wells

5-3

No. Report Name Engineer Drilling Contractor Boring Date No. of

Borings Soil/Rock

8 MWRD @ LASMA - STS Consultants Ltd. 1996 5 soil & rock

CUP-McCook reservoir LASMA

Site

- Patrick Engineering 1998 11 soil & rock

10 CUP McCook Reservoir - 5235.PO

Patrick Drilling Inc., Boart Longyear 1998 16 soil only (top of rock)

Patrick Drilling Inc., Boart Longyear 1999 2 soil only (approx. 10 ft into rock)

Patrick Drilling Inc., Boart Longyear, & Ruen 1998 10 soil & rock

CUP McCook Reservoir, DES

Plaines Chicago Sanitary and Ship Canal Soil Reports

STS Consultants Ltd. Lehtinen 1999 8 soil only

(top of rock)

McCook Reservoir, IL, Design

Documentation Report

- USACE 1999 17 soil & rock

73STR. TARP TUNNEL

RELOCATION

De Leuw, Cather &

Company Everest Engineering Co. 1999 3 soil & rock

14 CUP McCook Reservoir STS Consultants Ltd./JEL/GBM

Boart Longyear 2000 12 soil & rock

McCook Reservoir Groundwater Monitoring Wells

5-4

No.…