Response Analysis Of Buried Natural Gas Pipeline Under Oblique Slip Fault

Buried pipeline systems are an important way of natural gas transportation.Because spanning multiple geological units,pipelines and active faults often coexist in space,so the risk of pipeline active fault destruction is inevitable.Another major risk of natural gas damage comes from the corrosion of the pipeline itself.In this paper,the response of the buried natural gas pipeline under the action of active faults is selected as the starting point for the study.Using the ABAQUS software platform,the damage characteristics and influencing factors of buried natural gas pipelines with corrosion defects under the action of oblique slip fault displacement are systematically analyzed.To provide a reference for the pipeline's fault-resistant design,disaster-resistant reinforcement and maintenance strategy formulation.The main research contents of this article are summarized as follows:Firstly,The three types of failures under the action of buried pipelines are systematically analyzed,the types of faults and the failure mechanism of buried pipelines across faults are determined,and a strain-based failure criterion is proposed as an evaluation of pipeline dynamic response under the action of oblique sliding faults Reliability of the criteria.Secondly,Aiming at the torsional failure mechanism of buried pipelines and combining the failure characteristics of a buried pipeline during the Chichi earthquake in Taiwan,a non-linear finite element model of buried pipelines under the action of transversal-slip faults was established using ABAQUS.Among them,the MohrCoulomb constitutive model is adopted for the soil to simulate the large deformation state of the soil.The tri-fold line constitutive model is adopted for the buried pipeline to consider the elastoplastic deformation characteristics of the pipeline.The nonlinear friction contact model simulates the pipe-soil interaction.The size of the model is a semi-infinite space state that simulates soil.Thirdly,Based on the model of buried pipelines crossing faults,the effects of fault parameters,pipeline parameters,and soil parameters on the stress and strain response of the pipeline are systematically studied.The main influencing parameters are: fault type,fault displacement magnitude and direction,pipeline Buried depth,wall thickness,and internal pressure of the pipeline.Finally,Based on the ABAQUS software platform,a numerical model for buried pipelines with corrosion defects under the action of oblique and sliding faults is established.Displacement loading was used to simulate the displacement of the two disks of the fault,and the effects of the presence or absence of corrosion,the location of corrosion,the size of corrosion,the depth of corrosion,the radial length of the corrosion,and the circumferential length on the dynamic response of the pipeline were compared and analyzed.The simulation simulates the damage characteristics and evolution law of the corrosion defect on the buried pipeline oblique sliding fault.The research results in this paper not only well simulate the failure mechanism of buried pipelines under the action of oblique sliding faults,but also provide a good theoretical guidance for disaster-resistant design of buried pipelines across faults or the reinforcement of existing pipelines.