Western Regional Sanitary Sewer Conveyance Tunnel
Location: Boone County, Kentucky
Client: HDR/Quest Engineers, Inc.
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.