Abstract：The liquefaction of seabed under seismic load is one of the main reasons that govern the global stability of submarine pipeline. A finite element numerical analysis method for liquefaction around a buried pipeline in sandy seabed under seismic load is presented. The advanced soil static and dynamic universal triaxial and torsional shear apparatus is employed to perform torsional shear tests subjected to cyclic loading. The mode of dynamic increase of pore water pressure under undrained conditions gained from tests is incorporated with two-dimensional dynamic consolidation equation；and a numerical procedure based on FEM is developed to assess the accumulative pore water pressure. By numerical computation，the accumulation process of pore water pressure and liquefaction potential of sandy seabed soil under seismic load can be evaluated. Based on the presented numerical model，the effects of sandy soil characteristic parameters and pipeline geometry on the seismic-induced accumulative pore water pressure around submarine pipeline and along the depth of seabed are studied. By the computation and analysis，it is found that the effects of soil permeability coefficient on the seismic-induced accumulative pore water pressure ratios of sandy seabed around the pipeline are remarkable. Otherwise，the radius of pipeline only influence the accumulative pore water pressure ratios of sandy seabed nearby the pipeline；and the effects of pipeline can be neglected in the region of seabed far away from the pipeline.
