Determination of Limit Load to Buried Gas Pipeline with Inner Crack under Rockfall Impact Load Based on VCCT

Abstract

Rockfall is one of main load forms which result in rupture of buried gas pipeline. When the buried gas pipeline has constant pressure, the determination of the limit load of buried gas pipeline with initial crack under rockfall impact is very important for design optimization, safety operation and risk mitigation of gas pipeline. However, the prerequisite to solve this issue is to obtain the fracture parameters of buried gas pipeline with inner initial crack under the rockfall load condition and considering the interaction of buried gas pipeline and soil. In this article, the dynamic response of buried gas pipeline with inner surface semi-elliptical crack under internal pressure combined with rockfall impact load is carried out by using the finite element commercial code LS-DYNA. And then, fracture parameters of buried gas pipeline are evaluated by using the virtual crack closure technique (VCCT). Finally, the limit load for buried gas pipeline with inner crack is obtained based on tangent intersection criterion. The results and methods in this work can be referred in design and integrity assessment of gas pipeline.