Numerical method of lateral pipe-soil interaction and sensitivity analysis investigation

The pipe-soil interaction force is a crucial load that ensures the on-bottom stability of submarine pipelines and acts as a vital input parameter for the design of controlled pipeline buckling. It is necessary to precise prediction of soil lateral resistance and sensitivity to environmental parameters. This study developed a numerical simulation technique based on the coupled Euler-Lagrange (CEL) method to systematically analyse the deformation of the pipeline and the soil-pipeline forces on the seabed foundation during service. To validate the numerical method for large lateral displacement of pipe-soil interaction, an experimental approach employing parameter variation was utilized to conduct sensitivity analysis on the environmental parameters. The key parameters affecting soil-pipeline interaction were determined through an analysis of relative variation factors. The research findings demonstrate a satisfactory agreement, with an amplitude difference range of within 15 %, between the numerical simulation technique using the CEL method and the experimental results. This method resolves the issue of non-convergence due to grid distortion under conditions of large displacement, thereby enhancing computational accuracy. Sensitivity analysis shows that the relative variation factors for soil friction angle, initial burial depth, and soil density exceed 50 %, which is notably higher than the elastic modulus, friction coefficient, and Poisson's ratio of the soil. The results of this study enable the prediction of lateral forces in pipe-soil interaction and identification of environmentally sensitive parameters. This study establishes a foundation for calculating pipeline buckling strength in complex environments and holds paramount importance for the design and construction of pipelines to ensure on-bottom stability.