Full-Scale Laboratory Testing to Assess Methods for Reduction of Soil Loads on Buried Pipes Subject to Transverse Ground Movement

A series of full-scale tests were undertaken to examine the effectiveness of the use of geosynthetic materials to reduce lateral soil loads on buried pipelines subjected to transverse ground movements. The testing program consisted of measuring lateral soil loads on steel pipes buried in trenches simulating different native soil and backfill material configurations. The effectiveness of lining the inclined surface of the trench (i.e. “trench slope”) with two layers of geotextile as a method of soil load reduction depends on the formation of good slippage at the geotextile interface. Pipes buried in relatively soft native soil can penetrate into the native soil during lateral displacement, thus causing the geotextile-lining to be ineffective as a reducer of lateral soil loads. Although there is more opportunity for slippage at the geotextile interface when the trench is in relatively stiff soil, the soil loads on the pipe seem to still increase when the pipe moves in close proximity to the trench slope; this effect is likely due to the increased normal pressures on the pipe arising as a result of the presence of the stiff trench in the vicinity of the pipe.