Local buckling evolution mechanism of a buried steel pipe under fault movements

Abstract

AbstractPipe is the main transportation way for oil and natural gas. Fault movement mainly caused by earthquake, which will induce pipe bending, tension and compression. Then oil or gas leakage appear. Based on the moving mechanism of strike‐slip fault and reverse fault, a numerical simulation model was employed to study the buckling evolution mechanism of the buried steel pipe under fault movements. The evolution processes of buried pipe under the fault moving action were analyzed, and the effects of pipe internal pressure, fault displacement, and pipe diameter‐to‐thickness ratio on the pipe buckling were discussed. The results demonstrate that there are three mechanical evolution stages on the pipe in the process of fault movement. High stress appears on the bending regions of pipe wall, and axial strain always fluctuates along the axial length. When the fault displacement is large, pipe collapsing and wrinkling patterns occur, which can be reflected by a sharp fluctuation of axial strain. The high‐pressure pipe under the action of reverse fault is prone to failure than the low‐pressure pipe. The pipe with a large D/t in the hanging wall is easier to be buckled than that with a small D/t in the footwall. The results obtained can be used for the design and evaluation of buried oil and gas pipes.