Eastern Regional Wastewater Treatment Plant

October 1st, 2015

Location: Campbell County, Kentucky 
Owner: Sanitation District No. 1
Client: GRW Engineers, Inc.
Services: Geotechnical

THELEN provided the Geotechnical Services for the plant that will be the culmination of the new Eastern Regional collection system. The plant includes a preliminary treatment building, an equalization basin, two oxidation ditches, two clarifiers, ultraviolet disinfection, a sludge holding building and a sludge processing building. The plant will be expanded to twice its size. THELEN’s services during construction included testing of soils and concrete.


Work completed by Thelen Associates, Inc.




CSO 483 Drainage Basin

October 1st, 2015

Location: Clermont County, Ohio
Owner: Clermont County Water Resources Dept.
Services: Geotechnical

The CSO 483 drainage basin follows Kings Run Stream, which has been developed over the years, resulting in sections of the stream being culverted and upon which fill has been placed. The improvements within this basin will include new sewer alignments, an underground CSO surge tank, and several detention basins. Portions of the new sewer alignments will require open cut and shored excavations along with trenchless installation methods beneath an existing 14-foot by 8-foot combined trunk sewer. Installation of tied-back retaining walls will be required along portions of the sewer alignments to protect the proposed sewer during and after construction from potential slope instability. Thelen Associates, Inc. performed a geotechnical exploration for this project, which involved borings, laboratory testing, and slope stability analyses. This project is currently proceeding through the design phase.


Work performed by Thelen Associates, Inc.

Western Regional Sanitary Sewer Conveyance Tunnel

October 1st, 2015

Location: Boone County, Kentucky
Client: HDR/Quest Engineers, Inc.
Services: Geotechnical

Thelen is the geotechnical member of the design team for the Western Regional Conveyance Project in Boone County, Kentucky.  The project includes 32,574 feet of 9.5-foot diameter tunnel ranging from 35 to 300 feet below the ground surface; 702 feet of aerial, bridge-supported sewer as high as 43 feet above the ground surface, and 2,918 feet of 8.5-foot diameter open-cut sewer as much as 30 feet below the ground surface.  Thelen’s project engineering responsibilities have included the following: attending public meetings; logging the rock core and documenting geologic discontinuities such as faults, joints, and deep sand seams; determining the Rock Mass Rating (RMR) for the geologic formations of interest; managing an extensive in-house and out-sourced laboratory test program; evaluation of regional seismicity, site class, seismic design category, liquefaction potential, and seismic densification potential; design of a wick drain system to accelerate embankment settlements; design of deep foundations for the bridge structure; estimating long-term, open-cut sewer pipe settlements; geologic field mapping; an extensive geophysics program to define the bedrock/overburden contact in key areas of the driven tunnel alignment; interpretation of complex geologic overburden profiles in glaciated deep valleys; construction of geologic cross sections; foundation design for ancillary structures; production of the Geotechnical Data Report (GDR); assistance to the tunnel/bridge designer in assembling the Geotechnical Baseline Report (GBR); working with the Tunnel Review Board (TRB); and review of the plans and specifications. Our services commenced in February 2006 and were completed in November 2007.


Work performed by Thelen Associates, Inc.




Ameren Ash Pond Assessment & Monitoring

July 10th, 2013

Owner/Client: Ameren
Location: Multiple Power Plants throughout Illinois

Services: Geotechnical, Environmental

Geotechnology provided geotechnical and environmental consulting services with the purpose of evaluating the stability of ash pond embankments, develop groundwater monitoring wells and complete one round of groundwater sampling. This work was completed for eight Ameren Energy Resources power plant sites in Illinois.

Embankment stability evaluations focused on providing Ameren with information necessary to make decisions concerning the future study of the ash ponds. Global stability analysis was completed for each site which compared the sliding and restraining forces along possible slide planes and determining the factor of safety. The global stability analysis involved completing a number of subsurface borings per site and performing laboratory tests on samples obtained from the borings to develop geotechnical parameters needed to analyze slope stability.

The project also involved the installation of groundwater monitoring wells at the ash pond sites. Three to five monitoring wells were installed by Geotechnology’s drilling division for quarterly monitoring. Geotechnology completed the initial quarter of groundwater monitoring by developing the wells and then purging and sampling them.

Southwestern Illinois Levees

October 31st, 2012

Location: Southwestern Illinois
Client: AMEC
Owner: USACE – St. Louis District
Services: Geotechnical, Drilling

Overview: Geotechnology is providing drilling, Cone Penetromter Testing (CPT), and sampling at Prairie Du Pont and Fish Lake Levee Systems using hollow stem augers, mud rotary and wireline coring techniques. Disturbed and undisturbed samples were obtained in general accordance with ASTM standards. Additionally, the automatic standard penetration test hammers on each of our machines was calibrated in the field during the project. CPT were performed at 330 foot intervals on the levee riverside toe. Coordinated submittal results were sent to the Army Corps of Engineers – St. Louis District for analysis of slope stability and exit gradient.

America’s Central Port

October 31st, 2012

Location: Granite City, Illinois
Client/Owner: America’s Central Port
Services: Construction Observation and Quality ControlWater Resource Management

Geotechnology has recently finished up our services for design and construction of a new slip harbor on the east bank of the Mississippi River located at America’s Central Port (ACP) near Granite City, Illinois.  Once open, six railroads and four interstate highways with a lock-free public inland waterway environment will come together to create a multi-modal gateway of both national and regional significance.  The South Harbor will utilize the marine highway opportunity on the Mississippi River to transport cargo from points north of Chicago, Illinois to the ports of the Gulf of Mexico and beyond.  More than 3 million tons of cargo pass through the port each year. The ease of connecting river, rail, and road at one location will save both time and money.  The new harbor is expected to increase tonnage by 30 percent and create up to 800 full-time jobs.

A levee underseepage study was conducted to assess the impacts from planned developments, if any, and if required remediation(s) to the levee system at River’s Edge would need to be made to maintain seepage conditions acceptable to the Corps of Engineers, St. Louis District. Existing boring and well logs provided by the St. Louis District were reviewed to develop numeric models for several planned development scenarios, and conduct analyses to guide development of the remainder of the underseepage study.

Initial studies of existing conditions indicated that the exit gradient landward of the levee did not meet the Corps target value. In conjunction with development, the need for remedial measures regarding underseepage, such as additional relief wells, modeling planned fills on the levee inboard side as a seepage berm, or adding cut off walls to maintain an acceptably low exit gradient landward of the levee will be required. The underseepage study was completed by performing additional borings on the landward and river sides of the levee supplementing the Corps borings, gradation tests from which permittivity values of the sand were correlated, and detailed numeric studies using a spreadsheet model benchmarked to ground surface topography, stratigraphy, and hydraulic conditions specific to the site.

We provided construction observation and quality control testing during construction which included grain size analysis, moisture contents, Atterberg limits, Proctors, and compaction testing using sand cone and nuclear density methods per USACE specifications.  Laboratory testing was performed in our USACE-validated laboratory.  Construction tasks within the project included relief wells, a cut-off trench, harbor excavation, roadways, future building pad sites, and parking areas.  Approximately 560,000 cubic yards of soil was excavated and placed in various locations.

Natural systems consulting services have been provided to America’s Central Port since 2007. Wetland delineations of the 1,200-acre River’s Edge Development as well as an adjacent 63-acre site along the Mississippi River, identifying over 50 acres of wetlands and water courses have been performed. Currently, the project team is assisting TCRPD with biological assessments and mitigation services associated with a proposed harbor. To date, mitigation services have included reviewing thousands of acres in the project area for suitable wetland and stream mitigation as well as preparing a working mitigation plan.

This project has a significant amount of public and regulatory agency interaction and the team has been a crucial element in maintaining correspondence and attending meetings.

FeeFee Trunk FF-15 Sanitary Sewer Relief

October 31st, 2012

Location: Maryland Heights, Missouri
Client: BIS Frucon Engineering
Owner: MSD
Services: Water Resource Management, Environmental

Geotechnology has assisted BIS Frucon with environmental consulting, planning and data interpretation of contaminated environmental media, stream bank stabilization, and natural systems assessment tasks for this project. In addition, geomorphological observations were performed to evaluate stabilization recommendations, including composite revetment layered with native plantings, turf-reinforcement mats with native plantings, and grade control structures. As part of continued services Geotechnology is assisting with acquisition of the projects’ 404 and 401 permits. Geotechnology conducted a Sunshine Act file review and met with Missouri Department of Natural Resources (MDNR) personnel to develop a hazardous waste delisting request and work plan with the anticipation of minimizing construction costs associated with new sewer installation. In August 2011 Geotechnology received a letter from MDNR that officially delists the soil, groundwater and bedrock from being a listed hazardous waste. The implication of this delisting is significant: soil, groundwater and bedrock generated during the construction of the new sewer alignment will not be considered hazardous waste. The handling/disposal effort and costs associated with this designation will thus be greatly reduced.


October 23rd, 2012

Location: Various locations throughout Missouri and Illinois
Client: Numerous
Owner: Ameren
Services: Water Resource Management, Geotechnical, Environmental, Drilling

Services provided to Ameren include:

  • Coal Combustion Waste Improvements
  • Drilling
  • Ash Pond Assessment, Monitoring & Closure
  • Embankment Stability Evaluations
  • Geotechnical Engineering & Consulting
  • Environmental Engineering & Consulting
  • Groundwater Monitoring Well Installation & Monitoring
  • Laboratory Testing of Soils & Rock
  • Construction Materials Oversight & Testing

An example of projects performed for Ameren include: