Pipeline walking induced by cyclic temperature and pressure loadings is a challenge in the design of deepwater subsea pipelines. To investigate the walking mechanisms, a 3D non-linear finite element (FE) model incorporating realistic pipe-soil interaction is established. A parametric study is performed to analyze the effects of vertical geometric imperfections, seabed slopes, structural tensions, and transient thermal gradients. The results show that single-end tension and downhill slopes accelerate the walking rate, whereas dual-end tension and uphill resistance restrict or reverse the walking direction. Notably, the unique mechanism of vertical geometric imperfections is revealed: increasing the imperfection height suppresses walking by absorbing thermal expansion, whereas increasing the imperfection length exacerbates the walking rate. Based on the numerical results, the complex pipeline walking mechanism is explicitly decoupled, which provides an evaluation for the reliable design of deepwater pipelines.
ZHANG et al. (Mon,) studied this question.