Buckling behavior analysis of buried gas pipeline under strike-slip fault displacement

Long distance buried pipeline is the most important transportation way of natural gas. Strike-slip fault movement caused by earthquake is one of the threats for the structural integrity of buried pipelines. Bulking behavior of buried gas pipeline under strike-slip fault displacement was investigated by finite element method in this paper, considering soil-pipeline interaction in soil mass layer and rock mass layer. Effects of internal pressure, radius-thickness ratio and fault displacement on buckling mode and axial strain of buried pipeline were discussed. The results show that buried pipeline in rock mass layer is more prone to failure than in soil mass layer under strike-slip fault. With the increasing of fault displacement, deformation of the buried pipeline increases, and the flexure curve shape changes from S-shape to Z-shape. Buckling modes of the pipeline are different in the two layers, buried non-pressure pipeline appears local collapse in soil mass layer, while it is easy to be squished in rock mass layer. Buckling modes of pressure pipeline change from collapse to wrinkle gradually with the increasing of internal pressure, and the wrinkle amplitude also increases. In rock mass layer, number of buckling location for the pressure pipeline increases from two to three, and then increases to five with the increasing of fault displacement. With the increasing of radius-thickness ratio, buckling of the buried pipeline is more serious. Axial strain of pressure pipeline increases with the increasing of internal pressure and fault displacement.