Non-linear buckling analysis on buried X80 pipeline under the effect of reverse faulting

Buried high-strength steel pipeline is the main mode of long-distance oil and gas transportation, and its operation may be threatened by fault movement induced by earthquakes. In this paper, a finite element model was established for the buried X80 high-strength steel pipelines under the effect of reverse faulting. With this model, the pipeline was simulated by bends and pipe elements, and the pipe-soil interaction was simulated by the non-linear soil springs. In view of the non-linearity induced by the large geometric deformation, pipe material and pipe soil, the non-linear stability algorithm was adopted in this model to guarantee the convergence of solutions. Based on the engineering parameters of the Second West-to-East Gas Pipeline, two buckling failure modes of pipelines under the effect of reverse faulting were analyzed in detail, including the overall beam buckling failure and the local shell destabilization failure. Furthermore, the influences of the fault dip angle, pipe wall thickness and pipe burial depth on the buckling failure modes of pipelines were discussed. The research results provide the guidance for the design and safety evaluation of fault crossing pipelines.