Aged Tunnel Rehabilitation Options: Using Geotechnical Techniques to Assess Site Conditions and Provide Modeling Inputs: A Case Study from Detroit

摘要

Main components of Detroit's raw water tunnel infrastructure were constructed in the 1920s to 1950s. Approaching a century of continuous operation, underwater inspections revealed cracking of tunnel cast-in-place concrete liners and the potential risk of failure, requiring portions to be rehabilitated. The tunnels were installed within low-strength clays with dense "hardpan" at or near the invert. To assess the role of geologic conditions on the condition of the tunnels, a varied, multi-phased geotechnical program was performed. Techniques employed included sample borings, environmental screening, in-situ testing, instrumentation and laboratory testing to explore possible relationships between the tunnel conditions and surrounding soils. The dataset provides engineering parameters for three-dimensional numerical modeling of the tunnels and surrounding soils for advanced design phases of the project.