Effect of nonlinear pipe-soil interaction on lateral buckling of subsea pipelines triggered by a distributed buoyancy section

A distributed buoyancy section is one of the main buckle initiation techniques to trigger a pipeline to buckle laterally to release the high axial force induced by the high temperature of the transported fluid. A key design parameter governing the initiation of the lateral buckle is the breakout resistance. In this study, a nonlinear pipesoil interaction model is incorporated into the mathematical model to study the lateral buckling behaviour of the subsea pipeline triggered by a distributed buoyancy section. The numerical solution is compared with test results and analytical results in the literature to validate the mathematical model. A parametric discussion is carried out to investigate the breakout resistance, residual resistance and parameters of the distributed buoyancy section on lateral buckling behaviour. The results show that the breakout resistance has a great effect on the minimum critical temperature difference. The influence of breakout resistance on the buckling behaviour is much smaller than the influence of residual resistance. Moreover, the most optimal length of distributed buoyancy section should be equal to the length of the buckled section. Thus, the largest length of the buckled section during design should be estimated first to determine the optimal length of distributed buoyancy section.

Automated summary

This study investigates the influence of distributed buoyancy sections on lateral buckling behavior of subsea pipelines through mathematical models and parametric discussions. Analysis shows that breakout resistance, residual resistance, and parameters of the distributed buoyancy section have significant effects on lateral buckling behavior.