Application of 2D Finite Element Analysis on Subsea Pipe-Soil Interaction Assessment

Abstract

The behavior of a subsea pipeline when submitted to external loads is governed by the well predictable physical properties of the pipe and the not-so-well predictable pipe-soil interaction behavior. Understanding of the pipe-soil interaction behavior has advanced over the last years, however, the level of uncertainty in the available models is still high. This paper presents a series of detailed two-dimensional nonlinear finite element analyses investigating the soil resistance to pipeline lateral displacement. Parametric analyses were used to compare the influence of some important parameters such as the maximum (breakout) resistance, initial stiffness and mobilization displacements for example. Results are compared to the analytical models proposed by Verley, Lund and Bruton [1,2]. The results revealed some aspects not foreseen by the analytical models: The displacement under which the maximum lateral load is mobilized is not straightforwardly linked to the pipeline diameter, as some authors would say; the embedment seems to play a much more important role than the diameter itself in the maximum force derivation. Some other results are discussed through the paper and the main findings are listed in the conclusions.