15 Mile Road/Edison Corridor Sewer Tunnel Failure Study, Detroit Area, Michigan

摘要

The study consisted of field and laboratory investigations, construction evaluation, and geotechnical and structural analyses to determine the cause(s) of distress and failure of a 2600-ft section of 12-ft 9-in. diameter concrete-lined sanitary sewer tunnel in the Detroit, Michigan area. The work was performed at the request of the Environmental Protection Agency, Region V, Chicago, Illinois. The report includes summaries of all pertinent construction records, results of all pertinent past and current field and laboratory tests on construction and geotechnical materials, and detailed geotechnical and structural analyses based on observed conditions and measured parameters. Factors that could have potentially influenced or contributed to the distress were investigated; the findings eliminated certain possible factors and identified the essential causes and mechanisms. The conclusions are limited to those which could be made based on results of the analyses and facts and evidence documented in the report. The section of tunnel that experienced distress is at a depth of approximately 65 ft and was mined through lake-bed deposits that contain strata of silt and fine sand. The water table is normally approximately 20 ft above the invert but was drawn down for construction. The silts and fine sands are highly susceptible to piping under even small heads. Some of the construction joints in the concrete liner were made without waterstops and concrete placement procedures were such that cold joints occurred in the liner.