Abstract: This paper applies Biot’s consolidation theory and an elasto-plastic constitutive model on the post-liquefaction deformation of sand to investigate the wave-induced dynamic interaction between pipeline and seabed. The numerical simulations can reasonably reproduce the accumulation of excess pore pressure and the process of soil liquefaction around the pipeline induced by linear waves in the liquefiable finite seabed. The numerical results show qualitatively consistent with Sumer et al.’s results, and demonstrate conclusions as follows: The distribution of liquefaction in the seabed is significantly influenced by the pipeline, liquefaction first occurs at the seabed surface and underneath the pipeline, then transfers toward the soil surrounding the pipeline. Eventually, the entire sandy seabed around the pipeline liquefies, leading pipeline flotation. The degree of liquefaction in the soil around pipeline is intensified by pipeline. The soil liquefaction is induced by waves which is found mainly the combination of accumulation of excess pore pressure and seepage forces. The elasto-plastic method of dynamic analysis presents more rational result compared to the existing elastic method in simulating the changes of seepage field and stress field under wave actions for realistic ocean environment.

Key words: wave, saturated sandy seabed, pipeline, liquefaction, elasto-plastic method of dynamic analysis