A model of gas pipeline crossing earthquake fault based on beam-shell combined teaching element

Beam-shell element is usually combined to simulate gas pipelines, but it is difficult to figure out the distribution of beam-shell element and the coupling at the beam-shell junction. In this paper, the finite element model of gas pipeline crossing fault based on the beam-shell combined teaching element was established in light of the deformation characteristics of gas pipelines under the effect of earthquake faults. To meet the requirements of calculation efficiency and accuracy of pipeline deformation, the distribution of beam and shell elements was arranged rationally. And the influential laws of pipeline buried depth, crossing angle, fault displacement and fracture width on the mechanical behavior of gas pipelines were discussed using this finite element model. It is shown that the displacement and strain of gas pipelines are affected more by buried depth, crossing angle and fault displacement, but less by fracture width. The maximum axial strain of gas pipeline can be reduced effectively if it is buried in the shallow depth. With the increasing of the crossing angle, the maximum axial displacement and the maximum axial compression strain of gas pipelines are reduced significantly. In addition, the displacement and strain of gas pipeline are larger on both sides of the fault, while they decrease rapidly far from the fault. The research results provide the theoretical basis for the safety evaluation on the gas pipelines crossing earthquake faults.