Numerical modeling of response of a saturated porous seabed around an offshore pipeline considering non-linear wave and current interaction

The evaluation of pore pressure in the vicinity of an offshore buried pipeline is particularly important for pipeline engineers involved in the design of pipeline protection. Unlike previous investigations limited to linear wave loading, the seabed response around a buried pipeline due to combined non-linear wave and current loadings is investigated in this study. Based on third-order approximation for the wave–current interactions, a parametric study has been carried out to examine the influences of wave non-linearity and current on the pore pressure firstly. Numerical results demonstrate the significant effects of current in case of larger water depth, smaller period wave and fine sand. Then, the configuration and filled materials for a trench layer that normally is used for the protection of a buried pipeline are studied. The numerical results clearly show that an appropriate trench layer can reduce the risk of liquefaction around a pipeline.

► The first model considers combined wave nonlinearity and current around pipeline.
► Currents significantly affect the distributions of pore pressure around a pipeline.
► Significant effects of currents in deeper water, shorter period waves and fine sand.
► A trench layer with coarse materials will reduce liquefaction.