Dynamic response and limit analysis of buried high-pressure gas pipeline under blasting load based on the Hamilton principle

Abstract

For non-conservative systems consisting of elastic-plastic material, dissipative damping of a system in a dynamic environment involves two parts: (1) the dissipative energy related to the velocity of the mass point and (2) the dissipative energy associated with the strain rate. In this paper, the dynamic response of buried high-pressure gas pipeline under blasting load is studied, where, dissipation of energy is explicitly considered. The dissipative work was introduced into the Lagrange function. According to the Hamilton principle and finite element theory, a non-conservative explosion model composed of elastic and plastic materials was established to identify the dynamic response and the propagation characteristics of a detonation wave in the earth medium, where the explosion cavity with a triangle pressure time history on internal wall was used to describe the explosive stress from blasting buried gas pipeline. In the scheme of modeling, 15 cases of different explosive payloads, different distances from the explosion center and different wall thicknesses of the pipe were regarded as the generalized load were carried out. Then the specific dynamic responses of pipeline under blasting load were shown in the post processing, as well as the relationship between peak particle vibration velocity and explosion distance and payload. Using three types of limit analysis methods, the critical explosive loading, critical blasting center distance and critical wall thickness of a buried high-pressure gas pipeline under blasting loading were determined. The computational method and results in this paper could be referenced for security operation of a buried pipeline and blasting construction scheme.