Lateral Buckling of Subsea Pipelines Triggered by Sleeper with a Nonlinear Pipe–Soil Interaction Model

Abstract

Buckle-initiation techniques, such as sleepers, are usually installed to trigger lateral buckling at pre-designated locations to release the axial compressive forces induced by thermal loading. Taking the nonlinear pipe–soil interaction model into account, a mathematical model is proposed to investigate the lateral buckling of subsea pipelines triggered by a sleeper. The numerical solution is validated by comparing the model with solutions in the literature, and the model shows good agreement. The discrepancy between them is analysed by presenting the effect of mobilisation distance during buckling. The influence of the breakout resistance, sleeper height, and sleeper friction coefficient on the buckled configuration, post-buckling behaviour, and minimum critical temperature difference is discussed parametrically. The results show that the deformation of the buckled pipeline shrinks, and both the minimum critical temperature difference and the maximum stress along the buckled pipeline enlarge when the nonlinear pipe–soil interaction model is incorporated. However, the influence of the nonlinear pipe–soil interaction reduces with increasing sleeper height.