Simple solutions for downslope pipeline walking on elastic-perfectly-plastic soils

Pipeline Walking is a phenomenon that occurs when high pressure and high temperature pipelines experience axial instability over their operational lifetime, and migrate globally in one direction. Existing analytical solutions treat the axial soil response as rigid-plastic but this does not match the response observed in physical model tests. In this paper, the authors develop a new analytical strategy using elastic-perfectly-plastic axial pipe-soil interaction, which leads to more realistic walking rate predictions. The new analytical methodology is bench-marked with a series of Finite Element Analyses (FEA), which constitutes a parametric study performed to test the proposed expressions and improve on the understanding of the influence of axial mobilisation distance.