Lateral Force-Displacement Response of Buried Pipe in Lightweight Expanded Clay Aggregate

Lightweight expanded clay aggregate (LECA) has been used as backfill of gas and oil pipeline trenches for many years. Nine full-scale experiments were conducted to investigate the lateral force-displacement response of buried pipes in LECA at different burial depths. The experimental data indicated that the maximum lateral force on the pipe and the displacement of pipe at this maximum lateral force both increases with increasing burial depth and diameter of pipe. Comparison with tests for sand from the literature revealed that relationship between dimensionless force versus dimensionless displacement is similar to that of sand. Because of the light self-weight of LECA, the actual values of lateral force are much lower than that for sand. The displacement of pipe at the maximum lateral force are larger than that for sand. A modified formula that can be applied to the design of buried pipelines in LECA is given. The normalized dimensionless force and dimensionless displacement exhibit a parabolic relationship.