Dynamic response and limit analysis of buried gas pipeline under ground consolidation load

Currently, the significant dynamic plastic deformation of a buried gas pipeline frequently occurs due to the ground construction process that acts as a direct threat to the operation security of a buried gas transmission system. In this study, the pipe-soil interaction structure under a dynamic consolidation load, such as high energy dynamic compaction load, was considered as a non-conservative system in the work. Two parts of structure dissipation energy were introduced into the Lagrange function, and the elastoplastic dynamic equations of a non-conservative system based on the Hamilton Variation Principle (HVP) and the finite element (FE) theory were established. Implicit solution schemes were proposed based on the dynamic equations, and a steel weight-soil-buried pipeline finite element model was developed by performing a dynamic analysis in the LS-DYNA software with an explicit format. Vivid impact responses of an underground pipeline associated with the buried depth, wall thickness, and tamping energy were simulated. The plastic failure criterion of high toughness pipeline steel indicates that treated pipeline buried depth, wall thickness, and tamping energy corresponded to the generalized loads, and limit state of a specific case. So, they were recognized via the relationship of generalized load in relation to the total strain of pipelines. This was performed by using tangent intersection criteria, two elastic slope criteria, and zero curvature criteria. Additionally, the von Mises yield stress criterion was also applied as a traditional approach. The study potentially offers significant references on the quantitative pre-evaluation of a buried gas pipeline that poses as a threat due to the occurrence of third-party damage such as extreme strong ground interference.