Design safe distance between a buried pipe and a soil slope

摘要

Leakage from pipes buried in a soil slope can lead to failure and scour of the slope. Placing the pipe at a safe distance from the slope crest is a key concern in design. The objectives of the work reported here were to investigate the wetting front advancement in a soil slope due to leakage from buried pipes at variable distances from the slope crest considering different soil densities and boundary conditions of the slope, and to recommend a safe separation distance based on the relation between the factor of safety of the slope and the separation distance. Stability charts for slopes were established for different separation distances and infiltration times, which will serve as a guide to determining a safe separation distance. The safe distance depends on soil permeability, slope geometry and infiltration time. A safe distance, regardless of how long the leakage is expected to last, is recommended as twice the slope height for soil slopes 15 m in height and 35° in inclination compacted to 95% relative compaction under impermeable side and bottom boundary conditions. When a pipe is laid within this distance, the ability to detect and repair pipe leakage in a timely manner becomes an essential means of maintaining slope stability.