Basis_of_Design_Report_Attachment_4.pdf

APPENDIX D

PERMANENT SHEET PILE WALL DESIGN

100% DESIGN

APPENDIX D – PERMANENT SHEETPILE

WALL BASIS OF DESIGN

LOWER ROUGE RIVER – OLD CHANNEL

Prepared for

Prepared by Amec Foster Wheeler Environnent & Infrastructure, Inc.

March 2017

Honeywell International Inc.

Appendix D – Permanent Sheetpile Wall Basis of Design Lower Rouge River - Old Channel (LRROC)

Project No.: 3293161667 Page ii

T A B L E O F C O N T E N T S

1.0 INTRODUCTION

2.0 PROJECT BACKGROUND

2.1 DATUM

2.2 SITE DESCRIPTION

2.3 REGIONAL GEOLOGY

2.4 PLANNED REMEDIAL ACTION

3.0 GEOTECHNICAL EXPLORATION AND LABORATORY TESTING PROGRAMS

3.1 UPLAND GEOTECHNICAL EXPLORATION PROGRAMS

3.1.1 2012 Investigation

3.1.2 Pre-Design Investigation (PDI)

3.1.3 2016 Investigation

3.2 IN-RIVER GEOTECHNICAL EXPLORATION PROGRAMS

3.2.1 2011 Investigation

3.2.2 Pre-Design Investigation (PDI)

3.3 LABORATORY TESTING PROGRAMS

3.3.1 Pre-Design Investigation (PDI)

3.3.2 2016 Supplement Testing

3.3.3 Index Testing

3.3.4 Shelby Tube Logs and Photographs

3.3.5 Strength Testing

3.3.6 Consolidation Testing

3.3.7 Hydraulic Conductivity Testing

4.0 SUBSURFACE CONDITIONS

4.1 OVERBURDEN SOILS

4.1.1 Fill

4.1.2 Recent River Sediments

4.1.3 Organic Alluvium

4.1.4 Alluvium

4.1.5 Lacustrine Clay

4.1.6 Glacial Till

4.2 BEDROCK

4.3 GROUNDWATER

5.0 PERMANENT SHEETPILE WALL EVALUATIONS AND METHODS

5.1 SHEETPILE WALL ANALYSIS METHODOLOGY

5.2 SHEETPILE WALL MODEL DEVELOPMENT

5.2.1 Select Representative Cross-Sections

5.2.2 Establish Cross-Section Geometry

5.2.3 Establish Loading Cases

5.2.4 Establish Factors of Safety (FOS)

5.2.5 Use of Undrained Shear Strengths in Shoring Suite

5.3 GLOBAL STABILITY

6.0 EVALUATION RESULTS

6.1 PERMANENT SHEETPILE WALL

6.2 GLOBAL STABILITY

6.3 SHEETPILE DEADMEN

6.4 CONCRETE DEADMEN

Page iii

6.5 SETTLEMENT BEHIND THE SHEETPILE WALL

7.0 STRUCTURAL COMPONENTS

7.1 PERMANENT SHEETPILE WALL

7.2 SHEETPILE DEADMEN

7.3 BATTERED PILES

7.4 TIEBACK RODS

7.5 WALERS AND CONNECTIONS

8.0 REFERENCES

F I G U R E S

Figure 1 Cross-Section and Boring Location Plan (Former Detroit Coke)

Figure 2 Cross-Section and Boring Location Plan (Former Detroit Tar)

Figure 3 Cross-Section and Boring Location Plan (Ferriss Marine)

A T T A C H M E N T S

A Geotechnical Exploration Boring Logs

B Summary of Field and Laboratory Testing Data

C Cross-Section Geometry and Subsurface Stratigraphy

D Basis for Permanent Surcharge Loading

E Basis for Seismic Coefficient Selection

F Shoring Suite Output Files

G Slope/W Output Files

H Deadman Calculations

I Settlement Calculations

J Structural Calculations

Page iv

LIST OF ACRONYMS

AMEC Amec Environment & Infrastructure, Inc.

Amec Foster Wheeler Amec Foster Wheeler Environment and Infrastructure, Inc.

ASTM American Society for Testing and Materials bgs below ground surface bml below mud line bpf blows per foot

CIU Isotropically consolidated undrained CK0U K0 consolidated undrained Coleman Coleman Engineering Company, Inc.

EA EA Engineering, Science, and Technology, Inc., PBC

FOS factor of safety

GWTF groundwater treatment facility

Honeywell Honeywell International Inc.

kh seismic coefficient ksi kips per square inch

LRROC Lower Rouge River - Old Channel

MACTEC MACTEC Engineering and Consulting, Inc.

NAD North American Datum NAVD North American Vertical Datum pcf pounds per cubic foot PGA peak ground acceleration psf pounds per square foot PTI Post-Tensioning Institute

SPT Standard Penetration Test SU undrained shear strength

USCS Unified Soil Classification System UU unconsolidated undrained

Project No.: 3923161667

1.0 INTRODUCTION

Amec Foster Wheeler has prepared this Appendix to the Basis of Design Report to provide design basis information for the permanent sheetpile wall along the northern shoreline of the Lower Rouge River - Old Channel (LRROC) in Detroit, Michigan. The design of the permanent sheetpile wall will be prepared separately from the LRROC remedial sediment design, and construction for that work will be performed under separate contract. This Permanent Sheetpile Basis of Design Report comprises Appendix D of the LRROC Basis of Design Report (BODR).

The permanent sheetpile work will include the following general components:

Pretrenching and debris removal along the alignment of the sheetpile wall;

Pretrenching and debris removal/demolition along the deadman alignment;

Excavation and demolition within the limits of the tiebacks;

Installation of 2,540 feet of sheeting along the Ferriss Marine, former Detroit Tar, and former Detroit Coke riverfront, with up to five windows to allow for active utility and bridge passage across the LRROC and to avoid a bridge crossing;

Installation of deadmen located to the north of the sheetpile wall;

Installation of tiebacks between the sheetpile wall and deadmen. Note that installation of two groundwater collection trenches as part of the upland remedy (not part of the permanent sheetpile wall or LRROC remediation) must be performed prior to installation of tiebacks, and grouting of interlock of the permanent sheetpile (also not part of the permanent sheetpile wall or LRROC remediation) wall must be performed concurrent with installation of the sheetpile wall;

Backfilling behind the sheetpile wall, at tiebacks, and at deadmen to final grade;

Tensioning of tie-backs to mitigate deflection of the sheetpile wall during and after dredging; and

Interim surface restoration at the former Detroit Tar site, and permanent restoration (loaming and seeding with occasional gravel roads) at the Ferriss Marine and former Detroit Coke sites.

This report briefly summarizes existing site conditions, site-specific subsurface exploration programs, and subsurface conditions encountered, and describes the analyses performed and presents the results of the analyses.

2.0 PROJECT BACKGROUND

The following subsections identify the project datum and provide a general description of the site.

2.1 Datum

Elevations reported herein are based on the North American Vertical Datum (NAVD) of 1988, Geoid 2009. Elevations are reported in units of International feet. The horizontal datum is the Michigan State Plane coordinate system, North American Datum (NAD) of 1983, south zone.

2.2 Site Description

The LRROC is located in Detroit, Wayne County, Michigan, in a highly industrialized area along the northern and western boundaries of Zug Island. The LRROC is a 1.5-mile long channel connecting the Detroit River with the Rouge River around Zug Island.

The LRROC is surrounded by industrial developments dating back to the late 1800’s. Industries have included iron and steel mills, soda ash manufacturing, coking, tar, pulp and paper manufacturing, and shipping docks for bulk commodities such as coal, iron ore, concrete, petroleum products, limestone, cement, sand and gravel. Discharge from industry, stormwater outfalls, combined sewer overflows (CSOs), and non-point pollution sources have contributed to the accumulation of contaminants within the sediments of the LRROC over time.

Current land uses along the LRROC shoreline are primarily industrial and commercial facilities.

Along the proposed permanent sheetpile wall alignment, current facilities/properties include McCoig Holdings concrete manufacturing (Former Detroit Coke), the City of Detroit (Former Detroit Coke), the Honeywell International Inc. (Honeywell) former Detroit Tar facility (Detroit Tar), and Ferris Marine Contracting (Ferriss Marine). Riverbank crest elevations proximate to the proposed sheetpile wall alignment generally range from 581 to 585 feet. Based on site-specific topographic and bathymetric data, existing riverbank slopes generally range from 1.5H:1V (horizontal to vertical) to 3H:1V. The riverbank is currently laden with surficial debris.

Flow in the LRROC is primarily governed by the conditions of the Detroit River, with surface water entering from the Detroit River at the northeastern end of Zug Island, then flowing counterclockwise around Zug Island to the confluence with the main branch of the Rouge River.

Water elevations in the LRROC vary based on regional precipitation patterns and generally range from elevation 571.5 feet to 574.5 feet.

Structures present proximate to the proposed permanent sheetpile wall alignment include old pilings/moorings, docks, bulkhead walls, a water intake structure, bridge abutments, and fender pilings. There is one bridge crossing and one elevated pipe bridge (utility crossing) over the LRROC to Zug Island within the footprint of the proposed alignment. The Zug Island Road Bridge (a bascule lift bridge) is located at approximate wall station 104+60. A lateral line of fender pilings extends along the main land riverbank, beginning approximately 200 feet upstream of the bridge, and continuing underneath the bridge and extending approximately 50 feet beyond the bridge downstream. Existing structures along the LRROC are shown in Figures 1 through 3.

The City of Detroit, the Detroit Tar facility, and Ferris Marine sites contain various surface and subsurface utilities associated with former site uses and currently operating businesses. Known utility locations are depicted in Figures 1 through 3. The existing, known utilities include, but are not limited to, the following:

An 8-inch high voltage electrical line conduit running northeast to southwest buried just west of the existing groundwater treatment facility on the Detroit Tar site (Utility 18), and extends below the Rouge River channel to service the steel plant on Zug Island; this high voltage line reportedly provides power to a significant portion of the steel plant.

A large-diameter (36-inch diameter) storm water sewer discharges to the Rouge River approximately 90 feet east of the Zug Island Road Bridge.

A submerged utility tunnel that contains sewer force main, electric, and water (Utility 7), located approximately 250 east of the Zug Island Road Bridge, extends below the river channel to Zug Island.

Power cables (Utility 14a, 14b, and 15) located immediately west of Zug Island Bridge;

A series of electrical cables (Utilities 22, 24, and 28) near the contact of the Ferriss Marine and Former Detroit Tar sites.

The LRROC contains a federal navigation channel and both recreational and industrial vessels are allowed access to the LRROC. Due to the limited clearance of the Zug Island Bridge, the upstream channel geometry, and issues with water depth, the industrial traffic such as bulk carriers generally stay upstream of the Zug Island Bridge and downstream of the Delray Connecting Swing Bridge. Vessels such as tug boats do travel between the bridges to support operations at the Ferris Marine property. Recreational vessels, on occasion, navigate through the LRROC.

2.3 Regional Geology

The Areal Geology map of the Detroit, Michigan Quadrangle (State of Michigan Board of Geological Survey, January 1916 edition) generally maps the surficial geology of the site as lacustrine sand with alluvium along the LRROC shoreline. The Quaternary geology of Michigan surficial geology map (Michigan Department of Natural Resources, Farrad and Bell, 1982) defines the surficial material of the project site as lacustrine sand and gravel or lacustrine silt and clay.

2.4 Planned Remedial Action

The sediment remedy for the LRROC consists of a combination of dredging and engineered capping along with habitat enhancement. Sediment removal within the LRROC will consist of dredging approximately 73,500 cubic yards (cy) of sediment.

As part of the remedial activities, temporary and permanent sheetpile walls will be installed to stabilize the shoreline and upland structures prior to the start of dredging activities. The permanent sheetpile wall will be installed along the mainland bank of the LRROC between river stations 8+85 and 33+67 to allow for the complete removal of contaminated sediments.

Temporary sheetpile walls are planned in several locations along the LRROC dredge areas. In these areas backfill will be placed following sediment removal, and the sheetpiles will subsequently be removed.

Following dredging activities, an engineered cap will be installed in in the majority of areas where complete removal of contaminated sediments is not practical. The engineered cap will physically and chemically isolate the remaining contaminated sediments from overlying surface water and ecological receptors.

3.0 GEOTECHNICAL EXPLORATION AND LABORATORY TESTING

PROGRAMS

Several site-specific geotechnical investigations were conducted at the sites to support remedial design and design and construction of a permanent sheetpile wall. The intent of the investigations was to explore the subsurface conditions and determine the engineering properties of the site soils proximate to the proposed alignment of the bulkhead wall near the crest of the Rouge River riverbank (upland) and in the Rouge River (in-river).

3.1 Upland Geotechnical Exploration Programs

Three upland geotechnical exploration programs were recently performed at the Site. Boring logs for each exploration program are provided in Attachment A. Each exploration program is briefly described in the following subsections.

3.1.1 2012 Investigation

AMEC Environment and Infrastructure, Inc. (AMEC) subcontracted Coleman Engineering Company, Inc. (Coleman) to drill 18 geotechnical soil borings, designated GB-12-01 through GB- 12-18. The investigation was completed between July 9, 2012 and August 3, 2012. The soil borings were located along the LRROC waterfront on the Honeywell Detroit Tar, City of Detroit, and McCoig sites. Two of the borings (GB-12-13 and GB-12-14) were located on the Detroit- Windsor Truck Ferry property, to the east of McCoig. The borings were advanced to depths ranging from 26.6 feet to 86.6 feet below ground surface (bgs). Attachment A-1 provides detailed records of the drilling, testing, and sampling completed at each geotechnical soil boring location.

Boring locations are depicted in Figures 1 through 3.

3.1.2 Pre-Design Investigation (PDI)

EA Engineering, Science, and Technology, Inc., PBC (EA) subcontracted TTL Associates, Inc. to drill six geotechnical soil borings, designated OC14-GT-A through OC14-GT-F, as part of the pre-design investigation program. The investigation was completed between May 26, 2015 and June 1, 2015. Five of the soil borings (OC14-GT-A through OC14-GT-E) were located along the LRROC waterfront on the Ferriss Marine, Honeywell Detroit Tar, and City of Detroit sites and were advanced to depths ranging from 63 feet to 85 feet bgs. Attachment A-2 provides detailed records of the drilling, testing, and sampling completed at each geotechnical soil boring location.

Boring locations are depicted in Figures 1 through 3.

3.1.3 2016 Investigation

Amec Foster Wheeler Environment and Infrastructure, Inc. (Amec Foster Wheeler) subcontracted Coleman to drill four geotechnical soil borings, designated GB16-01 through GB16-04. The investigation was completed between February 24, 2016 and March 3, 2016 and was performed to collect supplemental strength properties of the lacustrine clay. Three of the soil borings (GB16- 01 through GB16-03) were located along the Rouge River waterfront on the Honeywell Detroit Tar and City of Detroit sites, and one soil boring (GB16-04) was located along the Detroit River waterfront on the Lafarge North America, Inc. property to the northeast of McCoig. The borings were advanced to depths ranging from 85.3 feet to 91.5 feet bgs. Attachment A-3 provides detailed records of the drilling, testing, and sampling completed at each geotechnical soil boring location. Boring locations are depicted in Figures 1 through 3.

3.2 In-River Geotechnical Exploration Programs

Two geotechnical exploration programs were performed in the LRROC. Boring logs for each exploration program are provided in Attachment A. Each exploration program is briefly described in the following subsections.

3.2.1 2011 Investigation

MACTEC Engineering and Consulting, Inc. (MACTEC) subcontracted Coleman to drill 11 geotechnical sediment/soil borings, designated GT-01 through GT-11, in the LRROC. The investigation was completed between May 21, 2011 and June 2, 2011. Six of the borings were located adjacent to the Honeywell Detroit Tar, City of Detroit, and McCoig sites, and five were located downstream from the Ferriss Marine site. The borings were advanced to depths ranging from 6 feet to 17.5 feet below mud line (bml). Attachment A-4 provides detailed records of the drilling, testing, and sampling completed at each sediment/soil boring location. Boring locations are depicted in Figures 1 through 3.

3.2.2 Pre-Design Investigation (PDI)

EA subcontracted Mateco Drilling Company (Mateco) to drill 16 geotechnical sediment/soil borings, designated OC14-GT-01 through OC14-GT-16, in the LRROC as part of the pre-design investigation program. Phase I of the investigation was completed between August 4, 2014 and June 4, 2014; phase II of the investigation was completed between December 10, 2014 and December 17, 2014. Thirteen of the borings were located adjacent to the Ferriss Marine, Honeywell Detroit Tar, City of Detroit, and McCoig sites, and three borings were located downstream from Ferriss Marine. The borings were advanced to depths ranging from 19 feet to

61.3 feet bml. Attachment A-5 provides detailed records of the drilling, testing, and sampling completed at each sediment/soil boring location. Boring locations are depicted in Figures 1 through 3.

3.3 Laboratory Testing Programs

3.3.1 Pre-Design Investigation (PDI)

EA subcontracted GeoTesting Express and Materials Testing Consultants, Inc. to conduct geotechnical laboratory testing of selected jar and undisturbed Shelby tube samples as part of the in PDI in 2014 and 2015. Results of laboratory testing are summarized in Attachment B.

Individual laboratory data reports are provided in Attachment B.

3.3.2 2016 Supplement Testing

The results of the testing performed on the lacustrine clay in the PDI showed drained strength results up to approximately 40 percent lower than anticipated for that soil, and the results indicated some disturbance of Shelby tube samples may have led to the lower results; direct use of that data would have resulted in an anchored king pile wall system instead of a more conventional anchored sheetpile wall system. Accordingly, Amec Foster Wheeler performed a supplemental laboratory program with a heavy focus on mitigation of disturbance was implemented. Results of laboratory testing are summarized in Attachment B. Individual laboratory data reports are provided in Attachment B.

The following subsections summarize the overall lab testing programs and procedures.

3.3.3 Index Testing

Index testing of soil samples obtained from Standard Penetration Tests (SPTs) and Shelby tube samples included the following:

Moisture content determinations (ASTM D 2216);

Organic content (ASTM D 2974);

Fines content (ASTM D 1140);

Particle-size analyses consisting of washed sieve only (ASTM D 422);

Particle-size analyses consisting of a combined washed sieve/hydrometer (ASTM D 422);

Atterberg limits tests (ASTM D 4318);

Oven-dried liquid limits tests (ASTM D 4318 and ASTM D 2487); and

Specific gravity determinations (ASTM D 854).

Index testing was performed in general accordance with the referenced ASTM procedures.

3.3.4 Shelby Tube Logs and Photographs

Logs of Shelby tube contents and photographs (standard tube opening) were performed. The logs included moisture content and density data, and a visual description of tube contents upon opening.

3.3.5 Strength Testing

Strength testing of soil samples obtained Shelby tube samples (fine grained soils) and from SPTs (coarse grained soils) included the following:

Laboratory vane shear (ASTM D 4648);

Unconsolidated undrained (UU) triaxial compression (ASTM D 2850);

Isotropically consolidated undrained (CIU) triaxial compression (ASTM D 4767);

K0 consolidated undrained (CK0U) triaxial compression (ASTM D 4767/GTX-S1020);

Direct simple shear (ASTM D 6528); and

Direct shear (ASTM D 3080).

3.3.6 Consolidation Testing

One-dimensional incremental consolidation tests were conducted on selected Shelby tube samples. Consolidation testing was performed in general accordance with ASTM D 2435, Standard Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading.

3.3.7 Hydraulic Conductivity Testing

Hydraulic conductivity tests were conducted on selected Shelby tubes samples. An effective confining pressure approximating in-situ conditions was applied to each specimen prior to testing.

Testing was performed in general accordance with ASTM D 5084, Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter.

4.0 SUBSURFACE CONDITIONS

The following subsections describe the site soil, bedrock, and groundwater conditions encountered, based on results of the pre-design geotechnical explorations and laboratory testing.

4.1 Overburden Soils

Subsurface conditions encountered in the upland borings from the ground surface downward generally consisted of fill overlying recent silt/clay sediments (in river), organic alluvium, alluvium, lacustrine sand and silt, lacustrine clay, and glacial till; however, not all strata were encountered at each borehole. In general, fill materials, lacustrine clay, and glacial till were interpreted to be continuous across the site while the sediments, organic alluvium and alluvium were discontinuous.

Subsurface conditions encountered in the river borings from the mud line downward generally consisted of river sediments overlying lacustrine clay and glacial till; each strata was interpreted to be continuous across the site.

A description of each soil stratum encountered is summarized in the following subsections.

4.1.1 Fill

Surficial materials encountered at upland borings varied across the sites and consisted of 3 to 4 inches of asphalt pavement, 6 inches of concrete, vegetation, or gravel and cobbles. The fill encountered below the ground surface materials generally consisted of brown to black fine to coarse sand with varying amounts of silt, gravel and cobbles. The fill contained considerable quantities of construction debris (brick, concrete, glass, and wood) in several locations. In several of the borings, it appeared that re-worked organic alluvium and alluvium were also used as fill materials.

Fill thickness ranged between approximately 5 and 31 feet. SPT N-values in the fill ranged from weight of hammer to greater than 50 blows per foot (bpf), indicating that the fill was very loose to very dense. The elevated N-values may be the result of the sampling equipment encountering gravel, cobbles, or debris.

The results of laboratory testing on fill materials are summarized in Attachment B.

4.1.2 Recent River Sediments

River sediment was encountered in each of the river borings. The sediment generally consisted of sand with silt and gravel, silty sand, sandy silt, clay with sand, and organic silt and clay. The sediment was generally classified as SP-SM, SM, ML or CH/OH soil in accordance with the Unified Soil Classification System (USCS).

The sediment encountered in the river borings was up to approximately 21 feet in thickness. SPT N-values in the sediment ranged from weight of rod/hammer to 7 blows per foot (bpf), indicating that the sediment was very soft to medium stiff (where material was cohesive) or very loose to loose (where material was predominantly granular).

The results of laboratory testing on river sediments are summarized in Attachment B. In-situ field vane shear test results in sediment are summarized in Attachment B.

4.1.3 Organic Alluvium

A stratified layer of organic alluvium, consisting of gray to brown/black organic clay to silty sand with organics, was occasionally encountered below fill materials or within alternating layers of alluvium in upland borings. The material contained occasional rootlets and organics. The organic alluvium was generally classified as SM or CH/OH soil in accordance with USCS.

The organic alluvium was encountered at depths ranging between approximately 5 to 26 feet bgs, with thicknesses ranging from approximately 2 to 6 feet. SPT-N values in this layer ranged from weight of hammer to 15 bpf, indicating that the stratum was very soft to stiff (where material was cohesive) or very loose to medium dense (where material was predominantly granular).

The results of laboratory testing on organic alluvium are summarized in Attachment B.

4.1.4 Alluvium

The alluvium, where encountered in upland borings, generally consisted of gray to brown silty fine to coarse sand and silt with some fine sand. The strata also contained occasional seams of gray silt and clay. The alluvium was generally classified as SM, SP-SM or ML soils, in accordance with USCS.

The alluvium was found at depths ranging from approximately 5 to 31 feet bgs, with thicknesses ranging from less than 1 foot to about 40 feet. SPT N-values in the alluvium ranged from weight of hammer to greater than 50 bpf, indicating that the stratum was very loose to very dense. The elevated N-values may have been influenced by the sampling equipment encountering oversized particles.

The results of laboratory testing on alluvium are summarized in Attachment B.

4.1.5 Lacustrine Clay

Lacustrine clay was encountered below sediment in river borings, and below fill, organic alluvium, or alluvium in upland borings.

In some borings, the upper portion of the lacustrine clay consisted of stratified, occasionally varved, brown to gray clay with silt and lesser amounts of sand and gravel. This upper stratified clay layer typically contained alternating seams/partings of fine sand and/or silt and was encountered at depths ranging from about 9 and 34 feet bgs, with thicknesses of approximately 1 to 14 feet. The stratified layer was generally described as moist to wet and very soft to stiff.

A relatively homogeneous gray clay layer, with lesser amounts of silt, sand, and gravel was encountered in each borehole either below the stratified clay or at the upper limit of the stratum.

The upper limits of the clay occasionally contained trace organics, presumably from its close proximity to the organic clay stratum in some locations. The homogeneous lacustrine clay was encountered at depths ranging from approximately 8 to 55 feet bgs in upland borings and approximately 1 to 21 feet bml in river borings. In general, the top of the clay stratum was encountered at greater depths in the eastern-most upland borings, proximate to the Detroit River.

The clay was fully penetrated at several locations during the investigations, where the thickness of the clay ranged from approximately 28.5 to 72 feet in upland borings and from approximately 30 to 50 feet in river borings. The homogenous clay layer was generally described as wet and very soft to medium stiff. The lacustrine clay was generally classified as CL in accordance with

USCS.

The results of laboratory testing on lacustrine clay, in-situ field vane shear test results, and summaries of lacustrine clay properties are summarized in Attachment B.

4.1.6 Glacial Till

Glacial till, consisting of silty, clayey gravel with sand, silty sand with gravel, and clay with sand was encountered below the homogeneous lacustrine clay in both upland and river borings. Where lacustrine clay was fully penetrated, the depth to glacial till ranged from approximately 78 to 87 feet bgs in upland borings and from approximately 46 to 59.5 feet bml in river borings, elevations ranging between approximately 495 and 505 feet.

SPT N-values in the glacial till ranged from 8 to greater than 50 bpf; in some cases refusal was encountered with split-spoon sampler, indicating that this stratum was dense to very dense, or hard in cases where the material was predominately cohesive, with increased density/consistency with depth. Glacial till was generally classified as GM, GC, SP, SM, and CL in accordance with

USCS.

The results of laboratory testing on glacial till are summarized in Attachment B.

4.2 Bedrock

Bedrock was confirmed in boring GB16-02A at a depth of 87.5 feet bgs. Bedrock consisted of light gray limestone. The bedrock was of very poor quality based on a Rock Quality Designation (RQD) index of 0 percent. The bedrock was slightly weathered and highly jointed/fractured (horizontal).

Artesian conditions were encountered within bedrock at a depth of approximately 86.5 feet bgs (approximately 6-inches into the top of bedrock) in boring GB16-03. Artesian head was measured to be at least 16 feet by extending flush-joint steel drill casing above ground surface.

4.3 Groundwater

Generally, groundwater has been historically encountered between approximately 3 and 16 feet bgs, typically within the fill materials or, depending on location, the alluvium or organic alluvium layer. Groundwater levels were measured in open boreholes either during or after drilling, where possible during the upland investigations. Water levels measured during the investigations are presented on the boring logs provided in in Attachment A. The measured depths generally ranged between approximately 4 and 11 feet bgs, and were found to be generally consistent along the riverbank crest. Groundwater levels generally become shallower with increased distance upland, away from the LRROC. Groundwater levels are subject to variation due to seasonal weather patterns and snow melt, and may vary from those observed during the investigations.

5.0 PERMANENT SHEETPILE WALL EVALUATIONS AND METHODS

Amec Foster Wheeler has assessed proposed sheetpile wall loading cases, and has performed permanent sheetpile wall geotechnical and structural design and stability evaluations to establish structural wall components. Limit equilibrium analyses have been performed. The following sections summarize the analysis methodology, describe model development, provide an overview of loading cases assessed, and discuss factors of safety (FOS) utilized.

5.1 Sheetpile Wall Analysis Methodology

Amec Foster Wheeler performed limit equilibrium analyses using Shoring Suite Version 8.12n (Shoring Suite), an industry-standard shoring design software developed by CivilTech Software USA, for the design of structural components of the wall. A limit equilibrium analysis evaluates stability with respect to both moment and horizontal force equilibrium and considers material (soil) strength.

5.2 Sheetpile Wall Model Development

The following subsections describe the Shoring Suite model development.

5.2.1 Select Representative Cross-Sections

The sheetpile wall alignment has been stationed from east to west from Station (STA) 100+00 to Station 125+40. Amec Foster Wheeler selected seven representative cross-sections along the sheetpile wall alignment considering upland final grades, the sediment remedy (i.e., dredging provided by Anchor QEA), interpreted subsurface stratigraphy, surcharge loading conditions, and available geotechnical data. Amec Foster Wheeler developed cross-sections at each of the following sheetpile wall stations:

STA. 103+00 (former Detroit Coke);

STA. 105+00 (former Detroit Coke);

STA. 112+00 (Detroit Tar);

STA. 118+00 (Detroit Tar);

STA. 121+50 (Ferriss Marine);

STA. 124+00 (Ferriss Marine); and

STA. 124+90 to 125+00 (Ferriss Marine).

Based on dredging profiles provided by Anchor QEA, localized deep dredge cuts are planned in four areas adjacent to the permanent sheetpile wall alignment, proximate to wall stations 104+50, 107+50, 114+50, and 116+00. It has been concluded that these localized deep dredge cuts will be performed using “slot-dredging” techniques, whereby dredging is performed in sections of limited length and width and backfilled to match adjacent, shallower sediment elevations. The rationale for this conclusion is provided in Section 6. The permanent sheetpile wall was not designed to support the localized deep dredge cuts.

5.2.2 Establish Cross-Section Geometry

In general, development of the models at each cross-section location consisted of the following steps:

A. Define Overall Geometry

The overall geometry (existing conditions) was defined based on site-specific topographic and bathymetric data. Existing topography and bathymetry are shown in Figures 1 through 3.

The overall geometry was then adjusted/modified to incorporate upland final grading and the sediment remedy (i.e., dredging) grades on the water side of the sheetpile wall. Dredged sediment elevations and slopes vary along the alignment of the sheetpile wall. Dredge contours are shown in Figures 1 through 3. Note that a 5-foot deep, 15-foot wide “bench” is shown in the dredge contours adjacent to the sheetpile wall for placement of scour protection riprap. This bench condition is representative of the temporary loading case described in Section 5.2.3. Scour protection riprap will slope upwards toward the sheetpile wall at a 3H:1V slope for final conditions (long-term loading case).

Low river elevation of 572 feet (all cross-sections).

Tiebacks/waler at elevation 575 feet (all cross-sections).

The following overall geometry was applied at each cross-section:

o STA. 103+00:

Top of wall elevation: 582 feet, sloping upward to 586 feet;

Groundwater elevation: 575 feet;

Dredge elevation at wall: 560 feet;

Dredge slope: 3H:1V; and Dredge elevation near center of channel: 539 feet.

o STA. 105+00:

Top of wall elevation: 582 feet, sloping upward to 585 feet;

Groundwater elevation: 575 feet;

Dredge elevation at wall: 561 feet;

Dredge slope: 3H:1V; and

Dredge elevation near center of channel: 540 feet.

o STA. 112+00:

Top of wall elevation: 581 feet, sloping upward to 583 feet;

Groundwater elevation: 574 feet;

Dredge elevation at wall: 558 feet;

Dredge slope: 3H:1V; and Dredge elevation near center of channel: 541.5 feet to 547 feet.

o STA. 118+00:

Top of wall elevation: 581 feet, sloping upward to 582 feet;

Groundwater elevation: 574 feet;

Dredge elevation at wall: 556 feet;

Dredge slope: 3H:1V; and Dredge elevation near center of channel: 543 feet to 545 feet.

o STA. 121+50:

Top of wall elevation: 582, sloping upward to 585 feet;

Groundwater elevation: 575 feet;

Dredge elevation at wall: 568 feet;

Dredge slope: 3H:1V; and Dredge elevation near center of channel: 545.5 feet.

o STA. 124+00:

Top of wall elevation: 581 feet, sloping upward to 584 feet;

Groundwater elevation: 575 feet;

Dredge elevation at wall: 567 feet;

Dredge slope: 3H:1V; and Dredge elevation near center of channel: 547 feet.

o STA. 124+90 to 125+00:

Top of wall elevation: 581 feet, sloping upward to 586 feet;

Groundwater elevation: 575 feet;

Dredge elevation at wall: 560 feet;

Dredge slope: 3H:1V;

Dredge elevation near center of channel: 546 feet; and

Sketches depicting the overall geometry at each of the selected cross-section locations are provided in Attachment C.

B. Define Subsurface Stratigraphy

Subsurface soil, bedrock, and groundwater profiles at each cross-section location were established based on the results of the geotechnical subsurface investigations described in Section 3.0. Available geotechnical data was utilized to define the primary soil strata depths, thicknesses, etc. Interpolation of depths, thicknesses, elevations, etc. between widely spaced borings was required for the development of each cross-section.

Sketches depicting the interpreted subsurface stratigraphy at each of the selected cross-section locations are provided in Attachment C.

C. Assign Material Properties

Unit weights for each sediment/soil were assigned based on soil type, in-situ conditions (e.g., relative compactness/consistency, above/below water table, etc.), empirical correlations to published literature values, laboratory test results, and engineering judgment.

Strength parameters for each sediment/soil were developed based on soil type, relative compactness/density or consistency, in-situ and laboratory test results, empirical correlations, and engineering judgment.

The specific unit weight and strength parameters applied for each soil stratum were as follows:

Table 5-1 – Summary of Soil Parameters Soil Stratum Unit Weight t

(pcf)1

Strength Parameters Effective

Friction Angle4

(o)

Undrained Shear Strength4 su , c

(psf)2

Embankment Soil and Alluvium5 120 32 -

Sediment 105 28 350

Lacustrine Clay (Upland) 125 23 600 – 11003

Lacustrine Clay (River) 125 23 400 – 5503

Glacial Till 130 35 -

Notes: 1. pcf = pounds per cubic foot.

2. psf = pounds per square foot.

3. Refer to Attachment B for design undrained strength profiles.

4. Effective friction angle and undrained shear strength parameters were not utilized concurrently in a given analysis for a single stratum.

5. Includes proposed backfill, existing fill/topsoil, organic alluvium, and alluvium.

5.2.3 Establish Loading Cases

The following loading cases were assessed at each selected cross-section location:

A. Long-Term

Long-term static loading conditions were assessed for each selected cross-section considering upland final grading, long-term groundwater conditions, surcharge loading (where applicable), and post-construction sediment elevations/slopes.

A surcharge load of 850 psf, 30 feet by 55 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Detroit Tar site (west of the groundwater treatment facility). The applied load represents surcharge imposed on the sheetpile wall by construction equipment (i.e., 100-ton crane) and potential soil stockpiles. The surcharge load was applied to cross-section STA. 118+00. Refer to Attachment D for surcharge load details.

A surcharge load of 725 psf, 23 feet by 12 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Ferriss Marine site (between STA. 124+50 and STA. 125+40). The applied load represents surcharge imposed on the sheetpile wall by an existing crane pad (i.e., 100-ton crane). It is our understanding that the crane pad is pile supported; however, because the information on piles is anecdotal and no drawings are available, it was conservatively assumed that the crane pad is not pile supported. The surcharge load was applied to cross-section STA.

124+90. Refer to Attachment D for surcharge load details.

Long-term static loading conditions were assessed considering drained strength parameters for river sediment and lacustrine clay strata. Drained strength parameters are generally considered to be representative of long-term strength conditions.

B. Short-Term

Short-term static loading conditions, immediately following dredging, were assessed for each selected cross-section considering upland final grading, long-term groundwater conditions, surcharge loading (where applicable), and post-construction sediment elevations/slopes.

A surcharge load of 850 psf, 30 feet by 55 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Detroit Tar site (west of the groundwater treatment facility). The applied load represents surcharge imposed on the sheetpile wall by construction equipment (i.e., 100-ton crane) and potential soil stockpiles. The surcharge load was applied to cross-section STA. 118+00. Refer to Attachment D for surcharge load details.

A surcharge load of 725 psf, 23 feet by 12 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Ferriss Marine site (between STA. 124+50 and STA. 125+40). The applied load represents surcharge imposed on the sheetpile wall by an existing crane pad (i.e., 100-ton crane). It is our understanding that the crane pad is pile supported; however, because the information on piles is anecdotal and no drawings are available, it was conservatively assumed that the crane pad is not pile supported. The surcharge load was applied to cross-section STA.

124+90. Refer to Attachment D for surcharge load details.

Short-term static loading conditions were assessed considering undrained strength parameters for river sediment and lacustrine clay strata. Undrained strength parameters are generally considered to be representative of short-term strength conditions.

C. Temporary

Temporary loading conditions were assessed for each selected cross-section considering construction conditions. The temporary loading condition considers final upland grading and over-dredging (up to approximately 5 feet) adjacent to the sheetpile wall face for placement of riprap for scour protection. The temporary condition at STA. 125+00 consists of design dredge conditions prior to sediment cap placement.

A surcharge load of 850 psf, 30 feet by 55 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Detroit Tar site (west of the groundwater treatment facility). The applied load represents surcharge imposed on the sheetpile wall by construction equipment (i.e., 100-ton crane) and potential soil stockpiles. The surcharge load was applied to cross-section STA. 118+00. Refer to Attachment D for surcharge load details.

A surcharge load of 725 psf, 23 feet by 12 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Ferriss Marine site (between STA. 124+50 and STA. 125+40). The applied load represents surcharge imposed on the sheetpile wall by an existing crane pad (i.e., 100-ton crane). It is our understanding that the crane pad is pile supported; however, because the information on piles is anecdotal and no drawings are available, it was conservatively assumed that the crane pad is not pile supported. The surcharge load was applied to cross-section STA.

124+90. Refer to Attachment D for surcharge load details.

Temporary loading conditions were assessed considering both drained and undrained strength parameters (not concurrently) for river sediment and lacustrine clay strata.

D. Pseudo-static (seismic)

Pseudo-static loading conditions were assessed for each selected cross-section considering final upland grading, long-term groundwater conditions, surcharge loading (where applicable), and post-construction sediment elevations/slopes.

A surcharge load of 850 psf, 30 feet by 55 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Detroit Tar site (west of the groundwater treatment facility). The applied load represents surcharge imposed on the sheetpile wall by construction equipment (i.e., 100-ton crane) and potential soil stockpiles. The surcharge load was applied to cross-section STA. 118+00. Refer to Attachment D for surcharge load details.

A surcharge load of 725 psf, 23 feet by 12 feet in plan, was applied 5 feet behind the sheetpile wall alignment on the western portion of the Ferriss Marine site (between STA. 124+50 and STA. 125+40). The applied load represents surcharge imposed on the sheetpile wall by an existing crane pad (i.e., 100-ton crane). It is our understanding that the crane pad is pile supported; however, because the information on piles is anecdotal and no drawings are available, it was conservatively assumed that the crane pad is not pile supported. The surcharge load was applied to cross-section STA.

124+90. Refer to Attachment D for surcharge load details.

The pseudo-static analysis method simulates earthquake-induced loads via the inclusion of a static horizontal force. The horizontal force, applied to the active and passive pressures of the sheetpile wall, is assumed to be proportional to the weight of the soil wedge times a seismic coefficient, kh, expressed in terms of the acceleration (in units of g) of the underlying earth. As a result active pressures increase and passive pressures decrease as a result of the seismic load. For long-term conditions, the design earthquake loading is based on a peak ground acceleration (PGA) associated with a probability of exceedance (PE) of 2% in 50 years (equivalent to a 10% PE in 250 years). The PGA is the maximum amplitude of the ground acceleration time-history. According to the United States Geological Survey’s (USGS) 2014 seismic hazards mapping data, the applicable PGA for the site is 0.06g. Refer to Attachment E for details.

Pseudo-static loading conditions were assessed considering both drained and undrained strength parameters (not concurrently) for river sediment and lacustrine clay strata.

5.2.4 Establish Factors of Safety (FOS)

A FOS was applied to each loading case, depending on the soil strength parameters used, in the form of a reduction in passive soil pressure consistent that presented in U.S. Army Corps of Engineers (USACE, 1994) guidance. Table 5-2 summarizes the FOS, or reduction in soil passive pressure, utilized for each loading case and strength parameter.

Table 5-2 Factors of Safety Loading Case Strength

Parameters Factor of Safety

(FOS)

Long-Term Drained 1.50

Short-Term1 Undrained 2.00

Temporary Drained 1.25

Undrained 1.75

Pseudo-Static2 Drained 1.10

Undrained 1.50

Notes: 1. An increase in the reduction of passive soil pressure is typically applied when using undrained soil parameters.

2. Application of the seismic load has a compound effect of increasing active pressure, and decreasing/reducing available passive pressure resistance, in addition to the FOS/passive reduction applied to the passive soil pressure.

5.2.5 Use of Undrained Shear Strengths in Shoring Suite

The developer of Shoring Suite software does not recommend the use of undrained shear strength parameters in the software, as it considers cohesion to be unreliable in shoring design.

However, the software provides and recommends the use of an “equivalent clay” soil type, whereby cohesion entered by the user is converted to NSPT and then to an effective friction angle (’) in accordance with the following tables from the Steel Sheet Piling Design Manual (USS, 1975). This “equivalent clay” soil type and conversion to drained strength parameters is presented below, and was utilized when undrained loading cases were assessed.

5.3 Global Stability

Amec Foster Wheeler performed a limited static slope stability evaluation of the LRROC riverbank slopes considering post-construction conditions at areas where the sheeting design calculations indicated that full sheeting penetration of the soft lacustrine clay was not required. The evaluation was made utilizing SLOPE/W (GeoStudio 2012, Version 8.12.3.7901), an industry-standard two-dimensional slope stability software program developed and distributed by Geo-Slope International, Ltd. The Spencer Method was used in the evaluation, which satisfies both moment and force equilibrium. The primary objective of the evaluation was to determine whether toeing the permanent sheetpile wall into underlying glacial till is required to achieve long-term global stability of the riverbank.

For most embankments, a minimum FOS of 1.5 is considered acceptable for long-term static stability under normal loading conditions; this minimum FOS is typically required by the majority of state and federal regulatory agencies for embankments where personal and/or environmental safety is a concern. For short-term loading conditions, it is typical to use a lower FOS in the range of 1.3. A FOS of 1.0 is considered as equilibrium conditions and represents conditions that are at or near failure; a FOS below 1.0 is considered unstable. Accordingly, in completion of this stability evaluation, the results (under both existing geometry and post-construction geometry) were compared to a FOS of 1.5 for long term conditions.

Amec Foster Wheeler developed a Slope/W model for cross-section STA. 121+50 (Ferriss Marine site), which was representative of where the sheeting design calculations indicated that full sheeting penetration of the soft lacustrine clay was not required. Overall model development proceeded similarly to Section 5.2. Stability considering both drained and undrained strength parameters for the lacustrine clay was assessed. Long-term stability of the embankment was assessed considering upland final grading, design dredge conditions, and installation of the permanent sheetpile wall to the depth specified by the Shoring Suite software results.

6.0 EVALUATION RESULTS

The following sections summarize the results of the permanent sheetpile wall analyses.

6.1 Permanent Sheetpile Wall

The following subsections and tables summarize the results of the analyses performed for each selected cross-section. Shoring Suite output files for the controlling loading case and strength parameter at each cross-section are provided in Attachment F. The following tables summarize the primary design parameters associated with the sheetpile wall: length required to achieve moment and force equilibrium, maximum applied bending moments, and tieback/waler loads required to achieve the specified FOS.

Table 6-1 – STA. 103+00 Sheetpile Results Loading Case Strength

Parameter Minimum

Sheetpile Length

LSheetpile

(ft)

Waler Load

PWaler-Sheetpile

(kip/ft)1

Maximum Moment

MSheetpile

(kip-ft)

Long-Term Drained 78 18.2 251

Short-Term Undrained 66 14.2 153

Temporary Drained 67 15.7 184

Undrained 61 13.4 136

Pseudo-Static Drained 68 17.9 208

Undrained 61 14.8 140

Notes: 1. kip = 1,000 pounds.

Table 6-2 – STA. 105+00 Sheetpile Results

Parameters

(kip/ft)

Long-Term Drained 79 19.8 283

Short-Term Undrained 66 14.9 164

Temporary Drained 68 16.9 205

Undrained 61 14.1 144

Pseudo-Static Drained 69 19.4 233

Undrained 61 15.7 149

Table 6-3 – STA. 112+00 Sheetpile Results

Parameters

Long-Term Drained 71 16.1 227

Short-Term Undrained 62 12.0 135

Temporary Drained 64 14.5 186

Undrained 59 11.7 129

Pseudo-Static Drained 64 16.2 197

Undrained 60 12.9 128

Table 6-4 – STA. 118+00 Sheetpile Results Loading Case1 Strength

Parameters

Long-Term Drained 73 21.7 267

Short-Term Undrained 65 19.0 199

Temporary Drained 64 18.3 195

Undrained 60 16.8 160

Pseudo-Static Drained 65 21.7 230

Undrained 60 19.8 188

Notes: 1. Surcharge load applied to all loading cases.

Table 6-5 – STA. 121+50 Sheetpile Results

Parameters

Long-Term Drained 64 12.3 127

Short-Term Undrained 54 9.4 71

Temporary Drained 54 10.3 81

Undrained 48 8.8 60

Pseudo-Static Drained 56 11.9 100

Undrained 49 9.6 61

Table 6-6 – STA. 124+00 Sheetpile Results

Parameters

Long-Term Drained 58 10.7 100

Short-Term Undrained 49 8.2 58

Temporary Drained 49 9.4 73

Undrained 45 8.0 54

Pseudo-Static Drained 50 10.1 80

Undrained 45 8.3 50

Table 6-7 – STA. 124+90 to 125+00 Sheetpile Results

Parameters

Long-Term Drained 74 21.3 2881

Short-Term…