OCWRC_Walnut CAP1 EFSD Siphon Removal_FKE Geotech Inv Report_24-162_04-27-2025.pdf

GEOTECHNICAL INVESTIGATION

REPORT

Prepared for

WALNUT LAKE NO. 1 PUMP STATION

CORRECTIVE ACTION PLAN

EFSD SIPHON REMOVAL

April 27, 2025

Excellence in Infrastructure and Underground Engineering

FK Engineering Associates

Project Number: 24-162 https://d.docs.live.net/15eac901cc41a6bc/Desktop/Siphons Geotech/Investigation Report/OCWRC_Walnut CAP1 Siphon_FKE

GeoRpt_F.docx

TABLE OF CONTENTS

1.0 PROJECT BACKGROUND

2.0 GEOTECHNICAL INVESTIGATION

3.0 DATA PRESENTATION

4.0 SUBSURFACE CONDITIONS

4.1 Soil Conditions

4.2 Groundwater Conditions

5.0 EVALUATIONS AND RECOMMENDATIONS

5.1 Soil Conditions

5.2 Groundwater Conditions and Control

5.3 Site Preparation and Recommended Earthwork Operations

5.4 Temporary Excavations and Earth Retention Systems

5.5 General Roadway and Pavement Recommendations

5.6 Trenchless Construction Considerations

5.6.1 General Trenchless Recommendations

5.7 Engineered Fill

5.8 Seismic Site Class

6.0 LIMITATIONS

Appendix A – FKE Geotechnical Investigation

Appendix B – Historical Information

Appendix C – Project Information

Excellence in Infrastructure and Underground Engineering

30425 Stephenson Hwy

Madison Heights, MI 48071

Mr. Evans Bantios, P.E. April 27, 2025

Chief Engineer FKE Project No. 24-162

Oakland County Water Resources Commissioner

One Public Works Drive, Building 95W

Waterford, Michigan 48328

RE: Geotechnical Investigation Report

Walnut Lake Pump Station No. 1 Corrective Action Plan

EFSD Siphon Removal

Southfield, Oakland County, Michigan

Dear Mr. Bantios, In general accordance with our proposal dated September 25, 2024, and subsequent conversations, FK Engineering Associates (FKE) has prepared this Geotechnical Investigation

Report for the proposed Evergreen Farmington Sanitary Drain (EFSD) Siphon Removal in

Southfield, Oakland County, Michigan, as part of the overall Walnut Lake Pump Station No. 1

Corrective Action Plan (CAP).

This report presents project background information, our field investigation activities, summary of subsurface conditions, and corresponding analyses and geotechnical recommendations for the proposed construction.

1.0 PROJECT

BACKGROUND

The Oakland County Water

Resources Commissioner

(OCWRC) is currently designing modifications to the EFSD, including reconstruction of the sewer to remove the existing siphon that is located at the northwest corner of

Southfield Road and 8 Mile

Road in Southfield, Michigan. The site location is shown in Image 1.

Image 1 - Site Location

Westhaven

8 Mile (M-102)

S o u th fi el d S er v ic e

D ri v e

S o u th fi el d F re ew ay

M -3

Project Site

N

FK Engineering Associates April 27, 2025

The existing siphon (and corresponding structures) was built under Contract PC-

637C by the Detroit Water and Sewerage

Department (DWSD), dated September

1986 as part of the Evergreen-Farmington

Relief Sewer. The 78-inch siphon runs south to north from 8 Mile to Westhaven to a junction chamber. At the junction chamber, there is an incoming 66-inch line from the west, and an outgoing 66-inch line to the east. These assets are currently operated by Great Lakes Water Authority

(GLWA) and are coordinated with

OCWRC. The site with color-coded facility owners is shown in Image 2.

The siphon project will generally include the construction of a new gravity sewer just above the existing siphon, connections to existing structures for the new gravity sewer, and abandonment of the existing siphon. The new sewer is proposed to be built using trenchless methods, specifically, horse-shoe hand-mining methods due to proximity to existing infrastructure, existing subsurface conditions, and potential use of existing access structures.

We understand that the existing siphon and associated pumps are to remain in operation until the new siphon can be put into operation. Existing sewers will be abandoned upon completion of the new sewers. The bottom of connecting chambers will also be raised during the abandonment of existing sewers. Table 1 summarizes existing and proposed sewer information.

Table 1 – New and Existing Sewer Information

Sewer

Existing

ID (in)

Existing Invert

El (ft)

Proposed

ID (in)

Proposed

Invert El

(ft)

Approximate

Length (ft)

Sewers to Be Abandoned New Sewers

Siphon (MH SOT140002 to

SOT140502)

78 618.7 66 627+/- 197

(SOT140007 to SOT 140502) 66 618.3 96 625.5+/- 70

(SOT140502 to SOT140503) 66 618.3 96 625.5+/- 28

Ex Flume Chamber to MH

SOT140002

78 627.3 66 627+/- 18

Image 2 - Site Layout / Existing Facility Ownership

N

8 Mile (M-102)

Ex Siphon

Ex. Outgoing 66-inch

Ex. Incoming 66-inch

Westhaven

Ex. Junction Chamber

Ex. 78-inch

Ex. Flume Chamber

FKE previously completed test borings at this site in 2020 for a separate OCWRC project. These test borings are discussed in Section 2.0, and provided in Appendix B. OCWRC has provided historical drawings for wastewater system elements for this project (PC-637). These are attached in Appendix B.

OCWRC has submitted a 50% Design Project Drawing Set to the Department of Environment, Great Lakes, and Energy (EGLE) on February 10, 2025. These are attached in Appendix C showing the overall project scope.

There is a 21-inch sewer abandonment component to the overall proposed project that is discussed under separate cover.

FKE was retained to perform design engineering services for OCWRC, including a supplemental

Geotechnical Investigation at the project site. Evaluations and recommendations in the following sections are based on our field investigation, laboratory testing, and proposed construction at the siphon site.

2.0 GEOTECHNICAL INVESTIGATION

Fieldwork for the geotechnical investigation was performed from January 27 to 28, 2025. Prior to beginning the geotechnical investigation, clearances for underground utilities were obtained using the Michigan one-call utility locating center (MISS DIG). Coordination with OCWRC was completed prior to drilling operations.

Our investigation consisted of drilling three test borings, designated as TB-201 through TB-203.

Each test boring was advanced to 60 feet below existing site grades. The typical drilling setup is shown in Image 3.

Historical test borings TB-8 and TB-

9 were advanced to 50 feet below grade.

See Figure No. 1 in Appendix A for approximate locations of the test borings. The indicated test boring locations were not surveyed for this project. Furthermore, the indicated ground surface elevations at the boring locations were estimated from site topography drawings and are considered approximate. Location plans and other figures were developed using Google Earth imagery. The specific information shown should be considered approximate and is intended for illustrative purposes only with respect to general information overlain on the Google Earth imagery.

Image 3 - Typical Drilling Setup (TB-201) - facing south

The test borings were drilled by our subcontractor, under observation from an FKE engineer, and were advanced using a CME-75 truck-mounted drill rig with 3¼-inch inside diameter, continuous flight, hollow stem augers to 10 feet, where 4-inch casing was set. Wash rotary drilling using a 3-7/8-inch tricone roller bit was performed from 10 feet to the explored depths.

Upon completion of drilling, borings were backfilled with cement grout until level with prevailing grade. TB-203 was backfilled with cement grout associated with the with the installation of a vibrating wire piezometer (VWP) at depth of about 50 feet. A flush-mount road box was installed within a quickset concrete pad at ground surface.

The test borings were generally sampled using the Standard Penetration Test (SPT) method

(ASTM D-1586) at 2½-foot intervals for the first 10 feet, and then at 5-foot intervals to 25 feet where 2.5-foot sampling was resumed to 45 feet, followed by 5-foot sampling to the explored depths. The SPT method consists of driving a 2-inch outside diameter split-barrel sampler into the soil with a 140-pound weight falling freely for 30 inches. The sampler is generally driven three successive 6-inch increments, with the number of blows for each increment being recorded.

The number of blows required to advance the sampler the second and third 6-inch increments is termed the Standard Penetration Resistance (N) and is presented on the individual Logs of Test

Boring. As added information, the blow counts for each 6-inch increment are also presented on the Logs of Test Boring.

All soil samples obtained with the split barrel sampler are designated with an “S” on the test boring logs. Recovered SPT samples were sealed in jars and transported to our office for further classification and select laboratory testing. Our engineer also recorded any groundwater level observations during and following completion of drilling where applicable.

3.0 DATA PRESENTATION

Data presented in the report attachments are organized as follows:

Appendix A – Geotechnical Investigation

− Figure No. 1: Location Plan

− Figure No. 2: FKE Soil Classification System

− Figure Nos. 3 through 5: Logs of Test Boring

− Figure No. 6: Log of Vibrating Wire

− Figure No. 7: Tabulation of Laboratory Test Data

− Figure Nos. 8 through 27: Individual Laboratory Test Results

− Historical Geotechnical Information (FKE 2020)

− Historical Plan Sheets

The FKE Soil Classification System defining the nomenclature used to describe soil conditions on the test boring logs and throughout this report is attached as Figure No. 2 in Appendix A.

Soils are classified by the material fraction which has the greatest impact on the engineering behavior (i.e., soils that exhibit some range of plasticity, and that will exhibit cohesion in the field, are described with the primary descriptor “Clay,” with secondary and tertiary descriptors according to the percentage of material by weight). For example, a sample that is 20 percent clay and 80 percent silt may exhibit cohesion, and have some range of plasticity, and therefore is described as “Silty Clay”. As presented in the FKE Soil Classification System, soils are described according to strength or density followed by color then by primary and secondary/tertiary components (i.e., soft gray silty clay or loose brown silty sand).

The stratification shown on the Logs of Test Boring represent the subsurface conditions at the actual boring locations. Variations may occur away from and between borings. Additionally, the stratigraphic lines represent the approximate boundary between soil types; however, these transitions may be more gradual than what is shown.

We have prepared the logs included with this report based on field classification supplemented with laboratory testing where applicable. Laboratory testing performed included:

− Unconfined Compressive Strength of Cohesive Soil (ASTM D2166)

− Laboratory Determination of Water (Moisture) Content of Soil and Rock (ASTM D2216)

− Standard Test Methods for Laboratory Determination of Density (Unit Weight) of Soil

Specimens (ASTM D7263)

Laboratory testing results may vary due to testing samples being disturbed during sample recovery. In addition to soil stratification, the Logs of Test Boring present groundwater observations, drilling and sampling information, and other relevant data.

4.0 SUBSURFACE CONDITIONS

The generalized subsurface conditions encountered in the borings at the location of the proposed construction are discussed in the following sections. Refer to the individual test boring logs for more specific information at the actual drilling location.

4.1 Soil Conditions

Test borings performed for this investigation and the historical borings performed at the site are generally consistent.

Surficial material consists of 2 to 6 inches of cohesive and granular fill with trace amounts of organic material (topsoil). Below the topsoil, generally loose to medium compact granular fill is present and extends to about 5 feet to 7 feet (El 658 to 561 +/-). Cohesive fill is present in TB-

202 to about 4 feet (El 660) and is underlain by loose granular fill to about 6 feet (El 658).

Below the fill, native very stiff to hard cohesive soil from about 5 to 15 feet (El 650) and is underlain by stiff silty clay that extends to about 54 feet (El 610). Below 54 feet, the soil consistency lowers to medium to stiff and extends to the explored depth of 60 feet (El 604.)

Occasional silt and sand seams are common within the native cohesive profile. A 3-inch sand lens is present in TB-203 at about 33.5 feet (El 632.5+/-).

4.2 Groundwater Conditions

Groundwater related observations generally made during our geotechnical investigations include:

− The approximate depth when groundwater is encountered during drilling: Groundwater readings upon completion of drilling were generally not recorded due to the introduction of drilling fluids into the boreholes. Groundwater was encountered during drilling historical boring TB-8 at about 4 feet (perched water) and was not present in our current test borings to 10 feet (depth when drilling introduced water to the borehole.)

− General soil layer color change from brown to gray: This color change is related to the oxidation of the soil minerals, which may be indicative of past (geologic) groundwater levels and/or level fluctuations. This is not necessarily indicative of the static/free groundwater levels at the time of drilling. Soil layer color change is observed between 5 to 7 feet (El 558 to 561) below grade.

− Borehole cave depth following auger removal: In predominately granular soil profiles, borehole cave depth may be indicative of the groundwater level at the time of drilling

(though comparison to observed groundwater levels at the time of drilling should also be considered). In predominantly soft cohesive soil profiles, borehole cave depth could be indicative of squeezing clay within the borehole (not necessarily an indicator of groundwater presence). This condition, if encountered, should be considered in concert with all other information contained on the test boring log. This condition was not experienced during this investigation due to grout backfill.

− Borehole heave during drilling: When encountered during hollow-stem auger drilling, heave indicates a hydraulic head difference between the surrounding soil and the interior of the drill stem. In Southeast Michigan, this is a common occurrence within predominately granular soil profiles once the groundwater table is encountered, or when a soil profile transitions from predominately cohesive to (saturated) granular soils (below the water table). Heaving is typically addressed by adding water into the augers to counter the hydraulic head difference, which prevents additional groundwater level readings during and following drilling. This condition was not experienced during this investigation.

Table 2 summarizes groundwater conditions as encountered in the test borings.

Table 2 – Groundwater Condition Summary

Boring No.

Groundwater

During Drilling3

(ft, Elev.)

Groundwater

After Drilling3

(ft)

Borehole Cave

Depth

(ft)

Brown to Gray

Transition

(ft)

TB-201 NE1 N/A2 N/A (GROUT) 6.5 (El 658)

TB-202 NE N/A N/A (GROUT) 6 (El 658)

TB-203 NE N/A N/A (GROUT) 5 (El 661)

TB-8 (hist) 4 (662) N/A N/A (GROUT) 4 (El 662)

TB-9 (hist) NE N/A N/A (GROUT) 5 (El 660)

1) NE – Not Encountered

2) N/A – Not Applicable

3) Wash rotary drilling techniques employed below 10 feet, which prevented further groundwater observations.

FKE installed vibrating wire piezometer VWP-203 within TB-203 upon completion of drilling.

Table 3 presents a summary of VWP readings to date. Image 4 graphically presents VWP data.

Table 3 – VWP-203 Summary

Date Pressure (psi) Head (ft, Elev)

2/18/2025 11.6 642.8

2/21/2025 11.5 640.7

2/24/2025 11.2 642.0

2/26/2025 11.0 641.6

Image 4 - VWP-203 Data

5.0 EVALUATIONS AND RECOMMENDATIONS

The following sections provide our evaluations and recommendations as they pertain to the proposed siphon replacement project.

5.1 Soil Conditions

The soil parameters provided in the following tables and figures were interpreted through consideration of laboratory testing results, field testing, historical information, and/or average and correlated values of soils as applicable.

As discussed in Section 4.1, test borings indicate 5 to 7 feet of variable fill overlying very stiff to hard clay to 15 feet, further underlain by generally stiff clay to the explored depth of 60 feet. The proposed tunnels have a finished inside-diameter of about 8 feet, from approximate El 625 to 633

(within medium to stiff clay). Mined tunnels and primary liners are expected to have a larger diameter than the finished diameter by about 2 feet +/-. Based on current and historical information, the clay at the proposed tunnel elevation interval should have limited squeezing under proper construction methods. The encountered soil conditions are expected to be favorable for trenchless construction.

The following table presents generalized soil parameters based on conditions encountered in our investigation.

Table 4 - Generalized Soil Parameters

Depth (ft, Elev.)

Generalized

Description

Avg

N

Valu e

Moisture

Content

(%)1

Friction

Angle (φ, °)2

Unconfined

Compressive

Strength (psf)1

Dry Density

(pcf)1, 2

0 – 5

(665 – 660) Granular FILL 10 - 30 - 100

5 – 15

(660 – 650)

Very Stiff to

Hard Silty Clay 17 13 - 8500 125

15 – 60

(650 – 605)

Medium to

Stiff Silty Clay 13 15 - 3000 120

1. Laboratory result or pocket penetrometer value, averaged if applicable.

2. Estimated from NAVFAC Design Manual

Blow counts and UCS estimates vary with depth. Images 5 and 6 present a graphical distribution of blow counts and UCS compared to depth. Current as well as historical test borings were considered in developing these figures. Blow counts generally increase after the soil transitions to cohesionless.

Image 4 - UCS vs Elevation

0 2000 4000 6000 8000 10000 12000

E le v a ti o n ft

UCS (psf)

UCS vs. Elevation

UCS - Test

UCS - PP

Proposed Tunnel

Existing 78-inch

Image 5 - N-Value vs Elevation

5.2 Groundwater Conditions and Control

As discussed in Section 4.2, groundwater was not encountered to 10 feet during this investigation. Further, groundwater was only encountered in historical TB-8 at 4 feet.

Considering the presence of granular fill soils underlain by deep, thick native cohesive soils, observed groundwater is likely perched groundwater. Perched groundwater is a local condition in which ground water is encountered higher than the static ground water level due to the presence of impermeable soils (clays) creating a tub-like effect. We anticipate that the impact from these conditions will be minor, and that recharge will typically be minimal and will eventually dissipate.

Significant groundwater is not anticipated during this project as tunneling will be performed through native silty clay soils. However, it is common for these soils to contain granular lenses and seams (also noted on our test borings). Based on experience, these granular seams can introduce groundwater to trenchless operations. This groundwater should be able to be managed by employing proper tunnelling approaches (i.e., mining upgrade) and use of sump pumping within the tunnel excavation. Groundwater that infiltrates into tunnel excavations is expected to be controllable using sumps located within and/or near excavations. Sump pumping is generally an economical unwatering method geared to achieve limited drawdown. This will likely involve numerous 2 to 6-inch sump pumps positions downgrade from the tunnel mining process. The

0 5 10 15 20 25 30

E le v a ti o n ft

N-Value

N-Values

N-ValuesProposed Tunnel

Existing 78-inch contractor should use a filter around the sump pumps to help limit/prevent pumping of soil particles, which can lead to excavation instability.

We recommend the following measures be considered by the contractor:

− Repeated construction traffic over exposed subgrade soils will result in rutting, pumping, and ponding. Temporary mats and/or gravel access should be used to protect surrounding areas where necessary.

− Site grading during construction should be done in such a manner as to channel (direct) precipitation run-off away from open excavations as much as practicable.

− Excavations should be left open for as little time as possible to protect the soils from disturbance by ponded water or construction traffic.

Additionally, groundwater levels may fluctuate with seasonal variations and periods of heavy or prolonged rainfall events. These factors should be considered during the construction and additional dewatering be performed as needed.

5.3 Site Preparation and Recommended Earthwork Operations

Regardless of the amount of earthwork required to achieve final grades, we recommend that all site preparation activities be performed under adequate specifications and be properly monitored in the field.

Existing underground utilities, foundations (at a minimum for the existing brick wall on the east edge of the site), or other miscellaneous obstructions encountered during site preparation activities should be removed, relocated elsewhere, or accounted for in the design. The resulting excavations should be backfilled in accordance with Project, OCWRC, and MDOT Standards and Specifications.

Subsurface Utility Engineering (SUE) Level A and B (daylighting and GPR/EM-locate) services were not provided as part of this geotechnical investigation. Available utility information is provided on the Project Drawings.

The contractor should enlist a positive means to protect the site from excessive disturbance during construction; this includes but is not limited to:

− Removal of vegetation, topsoil, pavement, and associated utilities in proposed construction footprint / lay down areas.

− Using construction mats to allow construction vehicles/equipment to traverse to the proposed construction area without damaging/rutting the surrounding area; and

− Avoiding the use of tracked vehicles on any existing pavements to remain after construction.

On-site soils are expected to be sensitive to disturbance when wet or when subjected to construction activities. If instability occurs, additional corrective procedures may be required including aeration, drying, and re-compaction, if weather conditions are conducive. If weather conditions are unfavorable and site conditions wet, subgrade preparation should be done by removal of the yielding soils and replacement with engineered fill where applicable. If deeper removal of soft or yielding soils is required beyond normal undercutting, these areas may be backfilled with 1-inch to 3-inch sized crushed aggregate to the top of subgrade. Deep undercutting operations should not generally extend below a depth of 18 inches unless specific conditions warrant.

In general, the site conditioning procedures discussed above are expected to result in stable subgrade conditions and a surface suitable for asphalt overlay throughout the site. If large areas of subgrade are unstable or are difficult to compact, the use of a geosynthetic, such as Tensar triaxial or interaxial grid with at least 6 inches of MDOT 21AA, may be considered for permanent and temporary roadways. The use of geosynthetics provides for more uniform conditions, likely allowing for a thinner pavement cross section.

5.4 Temporary Excavations and Earth Retention Systems

Should shallow excavation be required during construction, Michigan Occupational Safety and

Health Act (MIOSHA) and related regulations shall be followed, as well as any additional local regulations or owner requirements, and adequate protection provided for workers and adjacent structures, as applicable. In areas where there is inadequate space to allow for proper side slopes, vertical walls with properly designed and installed lateral bracing, or a combination of slopes and braced vertical walls may be used. In all cases, the

Not expected, but should deeper excavations from ground surface be required, use of a temporary earth retention system (TERS) may be required. Given the existing site constraints and the primarily cohesive soil profile, the following TERS are considered feasible:

− Steel sheet piling, steel plates, and/or a combination thereof.

− Soldier pile and wood lagging. This system consists of vertical H-piles installed below target excavation depth in caissons that are backfilled with grout or lean cement. As each excavation proceeds, lagging boards are installed between the H-piles while grouting the annular space between the boards.

− Walers with struts are typically used for internal bracing for both soldier piling and lagging and steel sheet piling TERS. These bracing systems will need to be considered during design of the permanent structure, as detailed staging of the construction sequence will be critical.

An experienced and licensed State of Michigan Professional Engineer should perform the shoring design. We recommend the following for proper shoring design:

− Construction surcharge load of 250 pounds per square foot (psf)

− Equivalent fluid pressure of 70 pounds per square foot per foot of depth (psf/ft) to account for lateral earth pressures acting on the temporary earth retention system.

Lagging provides for free drainage and prevents hydrostatic pressure build-up. If steel

Sheet Piling is used, weep holes should be considered.

− Construction traffic and excavated material stockpiles should be kept away from excavations a minimum distance equal to the full depth of the excavation unless the resulting surcharge loads are accounted for in the design of the lateral bracing system.

− The contractor’s proposed excavations, support systems, and sequence of construction should be reviewed by a qualified engineer prior to allowing the contractor to commence work.

− The use of limited benching, where practical, should be considered by the TERS designer to reduce TERS sizing.

− Bottom Stability Factor of Safety equal / greater than 1.5.

− Global Stability Factor of Safety equal / greater than 1.3.

5.5 General Roadway and Pavement Recommendations

Following removal of the existing pavement for the proposed construction, pavement will need to be replaced following applicable standards and under proper specification (MDOT and City of

Southfield).

MDOT uses mechanistic empirical pavement design for some roadways. This design method requires the use of a subgrade resilient modulus, Mr. The subgrade resilient modulus can be determined using several methods, including, but not limited to:

− Falling Weight Deflectometer (FWD)

− Plate Load Testing

− US Army Corps of Engineers (USACE) Dynamic Cone Penetrometer (DCP) Testing

− Visual Classification

For the purposes of this report, we have included the Mr based on MDOT’s published values for use in pavement design. MDOT’s User Guide for Mechanistic Empirical Pavement Design, Interim Edition dated March 2021. This investigation did not include investigation efforts within

8 Mile Roadway. Table 5 below presents values from MDOT Standards and Specifications should be followed for pavement design and construction. Regardless of the final pavement selection, a qualified Professional Engineer licensed in the State of Michigan should design the pavement cross section.

Table 5 - Subgrade Resilient Modulus Values

Subgrade Soil Type (USCS Classification) Resilient Modulus, Mr (psi)

Lean Clay (CL) 3700-5100

Silt (ML) 3700-5100

Clayey Sand (SC) 3700-5100

Clayey Sand – Silty Sand (SC-SM) 4200-5800

Silty Sand (SM) 4400-6000

Poorly Graded Sand (SP) 5500-7500

Poorly Graded Sand – Silty Sand (SP-SM) 5900-8100

All pavements require regular maintenance and occasional repairs to keep the pavements in a serviceable condition. The need for such maintenance and repairs is not necessarily indicative of premature pavement failure. If appropriate maintenance and repairs are not performed on a timely basis, the serviceable life of the pavement can be reduced significantly.

We recommend having a qualified field technician on site during construction to test and verify conformance of the density of base material, backfill material and asphalt or concrete.

5.6 Trenchless Construction Considerations

We understand that the existing sewers and structures are to remain in use during trenchless construction for the new sewers. Additionally, the proposed tunnel reaches are relatively short.

Therefore, the recommended method of construction is to utilize hand-mined trenchless (tunnel) construction. We understand that the finished inside diameters will range from 66 to 96 inches.

We expect the bored tunnel will have a horseshoe section with ribs and wood lagging as the primary liner. The final sewer pipe material (secondary liner) will consist of Hobas (or similar)

Fiber Reinforced pipe (FRP) with wall thickness of approximately 3 inches.

The subsurface conditions encountered in our investigation are favorable for hand-mining tunneling methods provided that the recommendations discussed in this report are properly implemented and monitored in the field.

Hand tunneling is a trenchless method where soil is mined by hand, often using pneumatic tools, and employs a cutting shield. Soil excavated by hand and hauled to the launching pit where it is removed from the site. The “launching pits” for this project will be the existing access structures.

As soil is mined, grade control can be maintained using this method (within 1 inch). Hand mined tunnel diameters range from 48 to 132 inches. Installation lengths vary and are flexible for project requirements. The lengths expected for this project are within this range.

Advantages for hand mining include:

− Precise installation

− Reduces vibrations to nearby infrastructure (existing sewers)

− Compatible with all pipe materials

− Accommodates most ground types

− Has been used successfully in the region

− Local contractors are experienced with this technique

− Does not require large laydown / shaft for a tunnel boring machine (TBM)

Disadvantages for hand mining include:

− Can have slower production than machine-aided tunnelling

− Requires manned-entry to tunnel

− Mining is challenging on variable face conditions (not expected for this project)

− Over-mining can occur relatively easily

Lining is installed immediately behind the tunnelling shield as mining progresses. The tunnelling shield should be prepared for unstable ground and groundwater conditions. Groundwater conditions can be eliminated using an adequate dewatering system.

Even in relatively short tunnel reaches, when mining in fine-grained soils (such as silty clay), excavation difficulties such as lumping, balling, and sticking should be expected. Fine-grained soils tend to clog cutterheads/spades, chamber, and conveyance systems.

Over excavation ahead of the shield can cause ground loss leading to ground surface settlement.

Ground settlement through shall be estimated by the tunnel designer. Care should be taken to minimize over excavation as much as practical.

5.6.1 General Trenchless Recommendations

We recommend a geotechnical monitoring program be implemented for this project. This should include monitoring points be installed and monitored on structures within 200 feet of the trenchless construction operations. Points installed on structures should be in accessible locations. Monitoring points should be installed and baselined in advance of initiation of mining efforts and be monitored daily during construction activities.

We also recommend a comprehensive precondition survey of nearby structures and pavements to document conditions before the start of construction activities.

The predominantly cohesive profile expected in the tunnel elevation intervales may contain some variable conditions, including granular seams that have groundwater, cobbles, and/or boulders.

Cobbles and boulders are common in glacial alluvial deposits, which the mining will be through.

The contractor should be prepared for the possibility of encountering these conditions.

OCWRC and MDOT standards for trenchless construction should be consulted for construction and design.

5.7 Engineered Fill

For work along 8 Mile Road, engineered fill should be placed in accordance with MDOT standards and specifications, and project standards and specifications.

We recommend that Controlled Low-Strength Material (CLSM) be considered for backfill around the permanent structures as needed. This material is considered “self-compacted” and

“self-leveling” and can be placed in lifts around the permanent walls. This tends to be a faster process than compacted engineered fill. We recommend that the CLSM be placed in lifts to not induce excessive buoyant forces on the permanent structure(s). We recommend that the contractor submit a CLSM mix design including a cold weather placement plan.

Material for backfill or engineered fill used for general site filling (where applicable) should consist of clean and well-graded granular soils (such as MDOT Class II Sand or equivalent). Fill should be placed in uniform horizontal lifts (layers) that are not more than 8 inches in loose thickness and compacted to achieve a density of at least 95 percent of the maximum dry density as determined by the Modified Proctor compaction test (ASTM D1557). In undercut areas or yielding areas encountered during proof rolling, 3-inch by 1-inch crushed stone may also be used. All engineered fill material should be placed and compacted at or near the optimum moisture content.

Frozen material should not be used as fill, nor should fill be placed on a frozen subgrade. Soil with organic content should not be used as structural fill.

Engineered fill used beneath floor slabs, roadways, and driveways (if needed) should consist of at least one foot of MDOT 21AA placed in uniform horizontal lifts (layers) that are not more than 8 inches in loose thickness and compacted to achieve a density of at least 95 percent of the maximum dry density as determined by the Modified Proctor compaction test (ASTM D1557).

5.8 Seismic Site Class

The seismic design category can be determined with ASCE 7-22. The Risk Category under

Section 1613 of the Michigan Building Code (MBC) (2015) / ASCE 7-22 shall be determined by a licensed structural engineer.

Based on the general soil profiles encountered in our investigation, and the procedures outlined in Chapter 20, Table 20.2-1 of ASCE 7-22, we recommend Seismic Site Classification D (stiff soil) be used for this site. If desired, further evaluation of the seismic site class with a deeper test boring to 100 feet deep, advanced technologies, such as multichannel analysis of surface waves

(MASW), or other appropriate methods may be utilized to potentially upgrade the site class.

6.0 LIMITATIONS

FKE has developed our evaluations and recommendations based on the data presented in this report and information provided by OCWRC, and design to-date, to formulate our original proposal and scope. We should be notified of any significant changes as our recommendations may require revision.

The report is intended for specific use in the proposed EFSD Walnut Lake No. 1 Pump Station

CAP – Siphon Removal Project in Southfield, Oakland County, Michigan as discussed herein. It was a pleasure providing geotechnical engineering services to you on this project. Should you have any questions or require additional information, please call.

Respectfully submitted, Peter F. Wenderski, P.E. Zachary F. Carr, P.E.

Project Engineer Project Manager

Attachments - PFW/TC/YK/ZFC

Appendix A – Geotechnical Investigation

Walnut Lake No. 1 Pump Station CAP

Southfield, Michigan

30-Apr-24

24-Feb-25

24-162 LP.dwg

1SOUTHFIELD, MICHIGAN

EFSD OUTLET SIPHON

OCWRC

1"=100'

24-162

PFW

TPC

ZFC LOCATION PLANS:

\P ro je ct F ile s\

P ro je ct

F ile s\

-1

O C

W R

C E

FS

D

O ut le t S ip ho n\

LP

\2 4-

LP

.d w g

2/

/2

7:

P

M

0 50'

Madison Heights, MI

REV # DATE REVISION TITLE

DRAWING SCALE:

CREATED ON:

PLOT DATE:

FKE PROJECT No.:

DESIGNED BY:

DRAWN BY:

CHECKED BY:

CAD FILE NAME:

248.817.2946

FIGURE NO.

OCWRC - EFSD OUTLET SIPHON

SCALE: 1" = 50'

1 INCH = 50 FEET

SO

U

TH

FIELD

R D

TB-203 (VWP)

TEST BORING DRILLED BY DLZ UNDER

FULLTIME OBSERVATION BY FKE ON

JANUARY 27 AND 28, 2025.

8 MILE RD (M-102)

SO

U

TH

FIELD

FW

Y (M

-39)

PROJECT

AREA

WESTHAVEN RD

WB 8 MILE RD

TB-201

TB-202

APPROX EX 78-INCH

APPROX EX 66-INCH

APPROX EX 66-INCH

SOT140007

SOT140503

SOT140502

(JUNCTION CHAMBER)

SOT140502

TB-8

TB-9

TEST BORING / VIBRATING WIRE

PIEZOMETER DRILLED BY DLZ UNDER

FULLTIME OBSERVATION BY FKE ON

JANUARY 28, 2025.

HISTORICAL TEST BORING BY FKE IN 2020.

SOIL CLASSIFICATION SYSTEM

1 of 1 Figure No. 2

SUMMARY OF SOIL NOMENCLATURE

Soils are to be classified by the fraction which has the greatest impact on the engineering behavior. Soils will be described according to a strength or density followed by color then by primary and secondary/tertiary components (i.e. soft gray silty clay or loose brown silty sand). United Soil

Classification System (USCS) descriptors (ASTM D2487) may also be used. Soils which exhibit unconfined shear strength will in most cases be described as cohesive soils regardless of their clay content whereas soils without unconfined strength will be described as cohesionless soils.

COHESIVE SOIL COHESIONLESS SOIL

Strength Unconfined Compressive Strength (psf) (Primary)

Pocket Penetrometer Test (tsf) (Primary)

SPT Value (N) (Secondary)

Density SPT Value (N)

Very Soft 0-500 0-0.25 0-2 Very Loose <4

Soft 500-1000 0.25-0.5 3-4 Loose 4-10

Medium 1000-2000 0. 5-1.0 5-8 Medium Compact 11-30

Stiff 2000-4000 1.0-2.0 9-15 Compact 31-50

Very Stiff 4000-8000 2.0-4.0 16-30 Very Compact >50

Hard 8000-16000 4.0-8.0 31-50

Very Hard >16000 >8.0 >50

MATERIAL SIZES AND IDENTIFIER GUIDE

Gravel 3/16 inches (No. 4 Sieve) to 3 inches Generally rounded rock particles

Coarse Sand 3/16 inches to 2 mm (No. 10 Sieve) Grains easily seen

Medium Sand 2 mm to 0.425 mm (No. 40 Sieve) Grains can be seen and felt

Fine Sand 0.425 mm to 0.075 mm (No. 200 Sieve) Grains can be felt

Silt 0.075 mm to 0.005 mm Easily cracks when rolled. Gritty feel. Dilatant.

Clay <0.005 mm Can be rolled. No particle size visible.

SECONDARY/TERTIARY SOIL COMPONENTS

Use secondary components when other than the primary soil appears in significant percentages. Generally the secondary component will compromise between 12 and 30 percent of the total soil weight. Tertiary components would be described as “little” and “trace” when the tertiary components are between 5 and 12 percent and less than 5 percent, respectively. The tertiary components would be inserted after the secondary and primary description (i.e. soft gray silty clay with little gravel and trace sand).

SAMPLE CODES

S Split Spoon Sample AU Auger Sample

LS Split Spoon Sample with Liner ST Shelby Tube Sample

BS Bag Sample P Piston Tube Sample

VS Vane Shear

This system is based on the USCS and MDOT’s Uniform Field Soil Classification System

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

13.5

15.5

12.7

14.4

131.9

128.0

9000*

9000*

6000*

4500*

3500*

664.7

658.5

651.5

635.0

0.3

6.5

13.5

30.0

FILL (4"): Brown SILTY CLAY with Little Sand and Trace Organic Material

FILL: Loose to Medium Compact Brown SAND with Trace Gravel

Hard Gray SILTY CLAY with Trace Sand and Gravel

Stiff to Very Stiff Gray SILTY CLAY with Trace Sand and Gravel

(occasional silt seams)

Drilling Method:

Drilling Date: 1/28/2025

1) * - Denotes pocket penetrometer value.Borehole drilled using a CME-75 truck-mounted drill rig with 3-1/4" ID HSA to 10'. Set 4" casing to 10', switched to wash rotary using 3-7/8" tricone roller bit to EOB.

Groundwater was not encountered during drilling to 10' (introduction of drilling fluid). Groundwater was not measured upon completion of drilling due to the introduction of drilling fluid at 10'.

Borehole backfilled with grout until level with prevailing grade.

Figure No. 3

Water Level Observation:

Plugging Procedure:

Notes:

Total Depth: 60 FT

Inspector: T. Coonan

Driller: V. Dearing Contractor: DLZ

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

5/

SOIL SAMPLE DATA

Sheet 1 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-201

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

5/

S-10

S-11

S-12

S-13

S-14

S-15

S-16

S-17

S-18

15.0

16.0

13.9

17.4

14.2

128.2

130.1

124.1

127.5

3000*

2000*

2500*

1500*

606.5

605.0

58.5

60.0

Stiff Gray SILTY CLAY with Trace Sand and Gravel (occasional silt seams)

Medium Gray SILTY CLAY with Trace Sand and Gravel

(occasional silt seams)

END OF BORING

SOIL SAMPLE DATA

Sheet 2 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-201

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

14.3

14.2

118.0

117.1

1500*

8500*

9000*

6500*

7000*

3000*

3000*

663.8

661.5

660.0

658.0

645.5

634.0

0.2

2.5

4.0

6.0

18.5

30.0

FILL (2"): Dark Brown Sand with Trace Organic Material

FILL: Medium Brown SILTY CLAY with Trace Sand and Gravel

FILL: Hard Brown SILTY CLAY with Trace Sand and Gravel

FILL: Loose Brown SAND with Trace Silt

Very Stiff to Hard Gray SILTY CLAY with Trace Sand

(occasional sand seams)

Stiff Gray SILTY CLAY with Trace Sand and Gravel

Drilling Method:

Drilling Date: 1/27/2025

1) * - Denotes pocket penetrometer value.Borehole drilled using a CME-75 truck-mounted drill rig with 3-1/4" ID HSA to 10'. Set 4" casing to 10', switched to wash rotary using 3-7/8" tricone roller bit to EOB.

Groundwater was not encountered during drilling to 10' (introduction of drilling fluid). Groundwater was not measured upon completion of drilling due to the introduction of drilling fluid at 10'.

Borehole backfilled with grout until level with prevailing grade.

Figure No. 4

Water Level Observation:

Plugging Procedure:

Notes:

Total Depth: 60 FT

Inspector: T. Coonan

Driller: V. Dearing Contractor: DLZ

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

5/

SOIL SAMPLE DATA

Sheet 1 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-202

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

S-12

S-13

S-14

S-15

S-16

S-17

S-18

4.5

14.3

18.5

15.0

15.0

17.6

116.9

115.2

120.1

117.8

112.0

3500*

2500*

1500*

1500*

610.5

604.0

53.5

60.0

Stiff Gray SILTY CLAY with Trace Sand and Gravel

Medium Gray SILTY CLAY with Trace Sand and Gravel

END OF BORING

SOIL SAMPLE DATA

Sheet 2 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-202

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

13.5

15.3

15.6

118.3

122.4

8000*

8000*

2000*

665.5

661.0

652.5

636.0

0.5

5.0

13.5

30.0

FILL: (6"): Light Brown SANDY CLAY with Trace Organic Material

FILL: Loose to Medium Compact Dark Brown SAND with Trace Clay

Hard Gray SILTY CLAY with Trace Sand (occasional sand seams)

Stiff Gray SILTY CLAY with Trace Sand (occasional sand seams)

(no recovery in 15', 30' samples (2" sandy clay lens at 23.5')

Drilling Method:

Drilling Date: 1/28/2025

1) * - Denotes pocket penetrometer value.Borehole drilled using a CME-75 truck-mounted drill rig with 3-1/4" ID HSA to 10'. Set 4" casing to 10', switched to wash rotary using 3-7/8" tricone roller bit to EOB.

Groundwater was not encountered during drilling to 10' (introduction of drilling fluid). Groundwater was not measured upon completion of drilling due to the introduction of drilling fluid at 10'.

Installed VWP-203 with cement grout (S/N 2317672)

Figure No. 5

Water Level Observation:

Plugging Procedure:

Notes:

Total Depth: 60 FT

Inspector: T. Coonan

Driller: V. Dearing Contractor: DLZ

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

5/

SOIL SAMPLE DATA

Sheet 1 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-203

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

S-12

S-13

S-14

S-15

S-16

S-17

S-18

15.6

15.4

15.6

16.0

122.4

121.3

118.2

116.8

2000*

2000*

-606.0 60.0

Stiff Gray SILTY CLAY with Trace Sand and Gravel (no sample recovery in 32.5', 60' samples)

(3" sand lens at 33.5')

END OF BORING

SOIL SAMPLE DATA

Sheet 2 of 2

SAMPLE

TYPE/NO.

STD. PEN

RESIST.

(N)

REC

(in)

MOIST.

CONTENT

DRY

DENSITY

(pcf)

UNCONF.

COMP ST

(psf)

BLOWS /

6 inches

ORGANIC

CONTENT

LOG OF TEST BORING NO: TB-203

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon

PRO-

FILE

ELEV.

(ft)

SUBSURFACE PROFILE

DEPTH

(ft)

GROUND SURFACE ELEVATION:

LO

G

O F

T E

S T

B O

R

IN

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

WELL DETAIL

665.5

661.0

652.5

606.0

0.0

0.5

5.0

13.5

60.0

642.8

642.7

642.0

641.6

642.3

2/18/2025

2/21/2025

2/24/2025

2/26/2025

3/20/2025FILL: (6"): SANDY CLAY

FILL: Loose to Medium Compact SAND

Hard Gray SILTY CLAY

Stiff Gray SILTY CLAY

END OF BORING

0.0

60.0

Tremie Grout Backfill

Figure No. 6

Notes:

1) Refer to TB-203 for detailed subsurface conditions encountered.

Well Type:

Casing Diameter:

Casing Length:

Casing Type:

Wire Manufacturer:

Serial No.:

Total Depth:

Installation Date:

Inspector:

Contractor:

Driller:

Equipment:

PVC

Geokon 2317672

60.0 FT

1/28/2025 T. Coonan

DLZ

V. Dearing Refer to TB-203.

V

IB

R A

T

IN

G W

IR

E

L O

G

4-

T

E S

T B

O R

IN

G

S .G

P J

/2

5/

COMMENTSINSTALLATION SCHEMATICSUBSURFACE PROFILE

GROUNDWATER DATA

PRESSURE

(psi)

VIBRATING WIRE LOG: VWP-203

DEPTH

(FT)

PRO-

FILE ELEVELEV.

(FT)

DEPTH

DATE ELEV (FT)

GROUND

SURFACE ELEVATION:

666.0

TOP OF CASING

ELEVATION:

Project No: 24-162

FK Engineering Associates

Checked By: J.GRIFFINProject Location: Southfield, Michigan

Project Name: OCWRC EFSD Outlet Siphon V

IB

R

A T

IN

G

W

IR

E L

O G

4-

T E

S T

B O

R

IN

G S

.G P

J

/2

FK ENGINEERING ASSOCIATES PROJECT NO: 24-162

OCWRC EFSD Outlet Siphon

Southfield, MI

C la y

S ilt

F in e S an d

M e d iu m S a n d

C o ar se

S a nd

G ra ve l

L iq ui d

L im it

P la st ic

L im it

P la st ic ity In d e x

TB-201 S-6 20 645.0 3,618 15.0 12.7 131.9 - - - - - - - - - - -

TB-201 S-9 30 635.0 3,608 15.0 14.4 128.0 - - - - - - - - - - -

TB-201 S-11 35 630.0 2,934 15.0 15.0 128.2 - - - - - - - - - - -

TB-201 S-13 40 625.0 2,563 15.0 16.0 130.1 - - - - - - - - - - -

TB-201 S-14 42.5 622.5 3,140 15.0 13.9 138.4 - - - - - - - - - - -

TB-201 S-15 45 620.0 3,425 15.0 17.4 124.1 - - - - - - - - - - -

TB-201 S-16 50 615.0 3,667 15.0 14.2 127.5 - - - - - - - - - - -

TB-202 S-6 20 644.0 2,402 15.0 14.3 118.0 - - - - - - - - - - -

TB-202 S-9 30 634.0 3,384 15.0 14.2 117.1 - - - - - - - - - - -

TB-202 S-11 35 629.0 3,045 15.0 14.3 116.9 - - - - - - - - - - -

TB-202 S-13 40 624.0 3,562 15.0 18.5 115.2 - - - - - - - - - - -

TB-202 S-14 42.5 621.5 3,604 15.0 15.0 120.1 - - - - - - - - - - -

TB-202 S-15 45 619.0 3,426 15.0 15.0 117.8 - - - - - - - - - - -

TB-202 S-16 50 614.0 3,597 15.0 17.6 112.0 - - - - - - - - - - -

TB-203 S-7 25 641.0 2,258 15.0 15.3 118.3 - - - - - - - - - - -

TB-203 S-8 27.5 638.5 1,368 15.0 15.6 122.4 - - - - - - - - - - -

TB-203 S-11 35 631.0 2,112 15.0 15.6 122.4 - - - - - - - - - - -

TB-203 S-14 42.5 623.5 3,832 15.0 15.4 121.3 - - - - - - - - - - -

TB-203 S-15 45 621.0 3,854 15.0 15.6 118.2 - - - - - - - - - - -

TB-203 S-16 50 616.0 3,662 15.0 16.0 116.8 - - - - - - - - - - -

TABULATION OF LABORATORY TEST DATA

E le va tio n o f S a m p le T ip

(f t)

D e pt h o f S a m p le

T ip ft)

S a m p le N u m b e r

B o ri ng

T e st

P it

/ P ro b e

D si g n a tio n

PARTICLE SIZE DISTRIBUTION (%)

ATTERBERG

LIMITS (%)

A p p ar e n t S p e ci fic G ra vi ty

A S

T M

D

O rg a n ic

M a tte r

U n ifi ed

S o il C la ss ifi ca tio n

P e rm ea b ili ty cm /s e c)

In -P la ce

D ry

D e n si ty

(l b s/ cu

.ft

F a ilu re

S tr a in

U n co n fin e d C o m p re ss iv

S tr e n gt h p sf

N a tu ra l W a te r

C o n te n t ( o f d ry w e ig h t)

Figure No. 7

30425 Stephenson Hwy, Job No. 24-162 Date 2/4/2025 Sample No. TB-201 S-6 Tester JAG

Initial Height 2.9 in Wet Soil Weight 175.9 g

Initial Diameter 1.4 in Dry Soil Weight 156.0 g

Initial Area 1.5 in2 Water Content 12.7 %

Initial Volume 4.5 in3 Dry Density in pcf 131.9 pcf

Total Strain

Stress (psf)

0.1% 290 1.0% 665 2.0% 1,148 3.0% 1,543 4.0% 1,910 5.0% 2,184 6.0% 2,425 7.0% 2,632 8.0% 2,796 9.0% 2,877

10.0% 3,001 11.0% 3,132 12.0% 3,257 13.0% 3,373 14.0% 3,475 15.0% 3,618

Strain Rate 1% per min

Unconfined Compressive Strength Test

0% 5% 10% 15% 20%

St re ss (p sf

Strain

Figure No. 8

Job No. 24-162 Date 2/4/2025 Sample No. TB-201 S-9 Tester JAG

Initial Height 3.0 in Wet Soil Weight 190.1 g

Initial Diameter 1.5 in Dry Soil Weight 166.22 g

Initial Area 1.7 in2 Water Content 14.4 %

Initial Volume 4.9 in3 Dry Density in pcf 128.0 pcf

Total Strain

Stress (psf)

0.1% 53 1.0% 248 2.0% 531 3.0% 867 4.0% 1,204 5.0% 1,559 6.0% 1,894 7.0% 2,192 8.0% 2,456 9.0% 2,680

10.0% 2,874 11.0% 3,038 12.0% 3,192 13.0% 3,333 14.0% 3,460 15.0% 3,608

Strain Rate 1% per min

Unconfined Compressive Strength Test

0% 5% 10% 15% 20%

St re ss (p sf

Figure No. 9

Job No. 24-162 Date 2/4/2025 Sample No. TB-201 S-11 Tester JAG

Initial Height 3.0 in Wet Soil Weight 181.15 g

Initial Diameter 1.4 in Dry Soil Weight 157.49 g

Initial Area 1.6 in2 Water Content 15.0 %

Initial Volume 4.7 in3 Dry Density in pcf 128.2 pcf

Total Strain

Stress (psf)

0.1% 39 1.0% 212 2.0% 456 3.0% 756 4.0% 1,052 5.0% 1,371 6.0% 1,681 7.0% 1,934 8.0% 2,142 9.0% 2,299

10.0% 2,444 11.0% 2,573 12.0% 2,664 13.0% 2,757 14.0% 2,847 15.0% 2,934

Strain Rate 1% per min

Unconfined Compressive Strength Test

0% 5% 10% 15% 20%

St re ss (p sf

Figure No. 10

Job No. 24-162 Date 2/5/2025 Sample No. TB-201 S-13 Tester JAG

Initial Height 2.9 in Wet Soil Weight 181.4 g

Initial Diameter 1.4 in Dry Soil Weight 156.39 g

Initial Area 1.6 in2 Water Content 16.0 %

Initial Volume 4.6 in3 Dry Density in pcf 130.1 pcf

Total Strain

Stress (psf)

0.1% 8 1.0% 94 2.0% 264 3.0% 473 4.0% 681 5.0% 900 6.0% 1,128 7.0% 1,325 8.0% 1,504 9.0% 1,667

10.0% 1,830 11.0% 1,958 12.0% 2,074 13.0% 2,220 14.0% 2,381 15.0% 2,563

Strain Rate 1% per min

Unconfined Compressive Strength Test

0% 5% 10% 15% 20%