Earth pressures on induced trench conduits.

摘要

The induced trench method of construction has been shown to significantly reduce the vertical earth pressures acting on a buried conduit. A compressible layer placed within the fill directly over the conduit induces differential settlement around the conduit. This differential settlement generates shear forces within the backfill material that help to support a portion of the weight of soil overlying the conduit.; The current induced trench design method based predominantly on work performed in 1922. Experimental induced trench installations presented in the literature have reported significant reductions in vertical earth pressure on the conduit. However, the induced trench method of conduit installation is viewed with skepticism and as such is not frequently used. The American Concrete Pipe Association has omitted the induced trench design method from the 2001 edition of the Concrete Pipe Handbook to reflect this skepticism.; This study investigated earth pressures around an induced trench conduit through centrifuge modeling, numerical analysis, and review of information presented in the literature. Key variables associated with induced trench installations were examined to determine their effect on the earth pressures around the conduit. The earth pressures obtained from the study are used to assess current design methods.; The study found that the induced trench method of construction resulted in a significant reduction in vertical earth pressures acting on the conduit. Variables such as compressibility, thickness and width of the compressible layer, type of backfill material and foundation conditions at the site were found to effect the earth pressures acting on an induced trench conduit. The most common method of design was found to provide a conservative estimate of the vertical earth pressure on the conduit.