A novel approach for time-dependent axial soil resistance in the analysis of subsea pipelines
A novel approach for modelling axial pipesoil interaction, consisting of bespoke finite elements, is proposed. The purpose is to have a model that represents a two-dimensional slice of soil perpendicular to the pipe which is computationally cheap enough to be incorporated in global analysis of subsea pipelines, whilst capable of capturing detailed time-dependent soil response, which involves partial drainage and cyclic plasticity. This is achieved by handling the circumferential dimension analytically, reducing the behaviour of the two-dimensional soil slice to a one-dimensional case. Coupled consolidation analysis along a vertical sequence of one-dimensional elements beneath each pipeline node, tailored to represent the axialvertical (or -radial) plane across the seabed semi-space, is supplemented by an analytical solution for the circumferential drainage. The paper presents the model development, its implementation through symbolic programming and validation against previously published continuum finite element analysis results.
pipesoil interaction consolidation offshore pipelines finite-element modelling cyclic loading pipeline walking