Mechanical behaviour of model gas pipes buried into sand and loaded in surface

This study focuses on the behaviour of buried gas pipelines subjected to surface loading. The study is oriented towards an experimental campaign carried out on small-scale pipelines, with three different wall thicknesses, both in monotonic and cyclic conditions. Pipes have been instrumented with strain gauges and inner displacement sensors, allowing to record deformations, stresses and ovalisation of the pipe, in addition to the load–settlement relationship at the soil surface. Results show that the presence of the pipe affects the global soil response (stiffness and bearing capacity). Analysis of the strain distribution and pipe deformed shape indicate that the pipe response is complex, with no symmetry along the horizontal axis, and a heart-shaped deformation pattern. The pipe rigidity affects the local behaviour at the pipe level (displacement pattern, evolution of stresses during cyclic loading and increasing lateral support). Classical pipeline design theory has been assessed based on the experimental observations, invalidating several underlying hypotheses.