Buckling failure mode analysis of buried X80 steel gas pipeline under reverse fault displacement

High strength steel pipeline is widely used in long distance transportation of natural gas. These pipelines are vulnerable under active faults in strong seismic areas. The buckling failure modes of high strength X80 gas pipeline crossing reverse fault were analyzed systematically in this paper. Based on the nonlinear finite element method, a pipe-elbow hybrid model was developed for buckling failure analysis of X80 steel pipeline under reverse fault displacement. The pipe soil interaction relationship was simulated by a series of elastic-plastic soil springs. The nonlinearity of pipe material and large deformation were also considered. The non-linear stabilization algorithm was selected due to the convergence of the numerical model. Engineering parameters used in the Second West to East Gas Pipeline in China were selected in this study. Typical features for beam buckling and local buckling failure in the proposed numerical model were derived. Based on a series of parametric studies, the influences of the fault displacement, fault dip angle, pipe wall thickness, buried depth of pipe and soil conditions on the buckling failure modes were discussed in detail. The proposed methodology can be referenced for failure analysis and strength evaluation of pipelines subjected to reverse fault displacement.