An Analytical Approach for Strain Analysis of Buried Steel Pipeline in Mining Subsidence Areas

Mining subsidence is one of the typical geological hazard threats for long distance oil and gas pipeline. Pipelines in subsidence areas will encounter complex load conditions, which probably will lead to rupture or local buckling failure. An analytical strain calculation model for steel pipeline in mining subsidence areas was proposed. Accuracy of the model was validated by comparing with the finite element results. Based on the proposed model, parametric study was conducted to investigate the influences of main effect factors on the pipe strain. Results show that, the maximum compressive strain occurs in the middle of the subsidence area, and the maximum tensile strain occurs on the edge of the subsidence area. Axial strain of the pipeline in the subsidence area increases with the increase of overlying strata stiffness, strike length and mining depth. But the mining thickness has a negligible effect on the axial strain. The increase of operating pressure, buried depth and pipe-soil interaction reduction factor will increase the axial strain, while a larger pipe wall thickness will induce a smaller axial strain.