Pipeline lateral buckling triggered by the residual curvature with tri-linear axial pipe-soil interaction

Abstract

Unburied subsea pipelines are vulnerable to lateral buckling due to high temperature and high pressure, which can be mitigated by inducing controlled lateral buckling through introducing residual curvatures at designable positions. The axial soil resistance is crucial in controlling buckling. Thus, a tri-linear pipe-soil resistance model is incorporated into the numerical model through springs in ABAQUS to study the influence of nonlinear axial soil resistance on lateral buckling. The effect of various factors on pipeline buckling is investigated, including the model length of pipeline, axial peak soil resistance, axial peak mobilization distance, axial residual soil resistance, and axial residual mobilization distance. Results demonstrate that insufficient pipe length inhibits buckling deformation at higher temperatures, which could reduce displacement amplitude and maximum stress. Pipeline buckling is significantly affected by axial resistance. The axial peak resistance and peak mobilization distance affect both pre-buckling and post-buckling states, while axial residual resistance and residual mobilization distance mainly affect post-buckling state. Therefore, in the engineering design of pipeline buckling, it is recommended to minimize the distance between adjacent residual curvatures that trigger buckling and to carefully select an appropriate axial soil resistance model that considers the actual field conditions.