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

Abstract

Pipe 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.

Local buckling behavior of buried pipeline under seismic oblique-reverse fault displacement

“…The buckling moment Mc and buckling stress σc corresponding to the cylindrical shell can be obtained by Eqs. ( 6) and (7) [27]:…”

“…The pipeline under the composed fault may be more dangerous and the pipe local buckling behavior (potential local buckling locations and the developing process) under single fault displacement may not accurately evaluate that under the composed fault. Besides, the local buckling of the pipeline as a cylindrical shell will experience an obvious stage feature under axial compression [7,20,21]. The clear developing process of the pipe local buckling is of great significance to the pipe safe operation and maintenance.…”

Mechanical Behavior of Polyethylene Pipes under Strike-Slip Fault Movements

“…In addition, it was concluded that cohesive soils, softer ground conditions, smaller diameter to thickness ratio, smaller pipe internal pressure and X80 steel material (compared with X65) result in a better deformation capacity of the buried pipeline. Similar FE models have been proposed and employed to describe mechanical behavior of steel pipelines crossing strike-slip faults taking boundary conditions into consideration [ 7 ], and mechanical behavior of steel pipelines crossing reverse faults [ 8 , 9 , 10 ] and oblique reverse faults [ 11 ]. In addition to the M-C model, the Drucker–Prager (D-P) model was, also, used to analyze mechanical response of steel pipe subjected to strike-slip fault movement with emphasis on the effects of fault modelling [ 12 ] and mechanical behavior of steel pipe under reverse fault displacement [ 13 ].…”

Coupling Interaction of Surrounding Soil-Buried Pipeline and Additional Stress in Subsidence Soil

“…The microscopic parameters of the model are calibrated by triaxial tests [15]. Zhang et al use a numerical simulation model to study the bending evolution mechanism of buried steel pipe under fault movement and discuss the influence of internal pressure of steel pipe, fault displacement, and diameterthickness ratio of steel pipe on the bending of steel pipe [16]. Liu and Wang introduce the nonlinear pipe-soil interaction model into the analysis of lateral global bending of pipelines and investigate the bending characteristics of submarine pipelines with single-arch symmetric initial imperfections under different pipe-soil interaction models [17].…”