Parametric study on the trench designing for X80 buried steel pipeline crossing oblique-reverse fault

Abstract

The safety operation of buried long-distance oil and gas pipelines has long been threatened by the active fault movement due to earthquake. In this paper, a three-dimensional numerical model of X80 buried pipeline crossing oblique-reverse fault was established considering the existence of pipeline trench and backfill soil. The values of parameters were derived from the Third West-to-East Natural Gas Transmission Pipeline Project in China. The strain development and deformation features of pipeline for local buckling and tensile fracture were obtained. The influence of various trench design parameters (pipeline burial depth, trench slope inclination, backfill soil type and thickness) on the failure process was discussed. Meanwhile, based on the failure criterion of buried pipelines, the critical fault displacements corresponding to different trench design schemes were studied. It is shown that the failure of pipelines can be avoided by reasonable trench design in the areas of low seismic intensity. Finally, the optimal scheme was further given to provide a reference for the seismic design of buried pipelines at oblique-reverse fault crossings.