Mechanical behavior of submarine pipelines under active strike-slip fault movement

This paper presents comprehensive results on the mechanical behavior of submarine steel pipelines subjected to various strike-slip fault displacement loads. The investigation uses strain-based criteria to estimate pipeline performance based on rigorous numerical modeling and simulation of a soil-pipe system, accounting for nonlinear material behavior and large strain of both pipeline and surrounding seabed soil. Equivalent boundary conditions are derived and applied at both ends of the pipeline to take the effect of pipeline segments far away from the fault into account. Parameters affecting the response of submarine pipelines subjected to active faults (including pipe diameter, diameter-tothickness ratio, burial depth, soil stiffness, and intersection angles) are studied. A uniform design experiment is also carried out to predict the critical fault displacement. The results show that the segments of the pipe embedded in both blocks near the fault plane are critical locations where buckling or rupture is more likely to occur. The ability of the pipeline to withstand more fault displacements can be enhanced by increasing the diameter and wall thickness. In addition, the choice of proper burial depth and differential pressure can lead to an increase in flexural stiffness and weaker soil-pipeline interaction. Pipe diameter, crossing angles, and burial depth determine the pipeline's failure modes. An accurate regression derived from finite uniform design experiments is proposed for the performance-based design of future submarine pipelines.