Failure Analysis and Finite Element Simulation of Above Ground Oil–Gas Pipeline Impacted by Rockfall

Abstract

Pipeline is the most important transmission way of oil and gas. Rockfall impact is one of the factors that result in above ground oil–gas pipelines accidents. Deformation of oil–gas pipeline caused by rockfall impacts were investigated using finite element method. Pipeline deformation caused by spherical and cube rockfalls were discussed under radial impact, inclined impact, and eccentric impact. The results show that crater depth of spherical rockfall impact is bigger than the cube rockfall with the same volume. The smaller curvature radius of rockfall’s contact zone has a greater harm to oil–gas pipeline. Angle part impact of irregular rockfall is very harmful for oil–gas pipeline. Under inclined impact, the maximum plastic strain of spherical rockfall impact crater appears when incidence angle α is 45°. Pipeline is prone to rupture when α is small under cube rockfall impact. The plastic strain distribution of the impact crater is more uneven with the increasing of the incidence angle. Plastic strain zone of pipeline decreases with the increasing of eccentricity k under eccentric impact.