Model Pit Test and DEM Analysis on Buried Pipe Subject to Lateral Loading

A bend in the pipeline with internal pressure will generate thrust externally. For a buried pipe, this thrust is supported by the passive earth pressure through the backfill at the bend, which is typically supported by the concrete block. The magnitude and the shape of distribution of the earth pressure are not readily known. In this paper, pit tests were conducted using a pipe model having 260 mm diameter and that was equipped with 20 bi-axial load cells on the surface. Similar tests were conducted using a plate for direct comparison. The earth pressure distributions acting on the pipe surface were observed. In addition, numerical analyses by distinct element method were conducted to clarify the mechanism of the behavior of the laterally loaded pipe. The test and the numerical analyses results indicated that the passive soil pressure distribution for a plate was uniform. However, in case of a pipe bend, the lateral earth pressure distribution was not uniform and it was affected by friction between the pipe surface and soil.