Towards the Numerical Modelling of Residual Seabed Liquefaction Using OpenFOAM

Abstract

Knowledge of the interaction between free surface waves and the seabed is required for the reliable design of marine structures, preventing severe structural failures. To that end, this paper presents the numerical modelling of wave-induced residual liquefaction of seabed soil. An OpenFOAM^® finite volume solver is developed to simulate the behaviour of pore pressure and shear stress in the soil and is validated against analytical reference data. The soil is considered as a poro-elastic solid and an additional equation is solved for the pore pressure buildup. The governing equations are valid only up to the onset of liquefaction. A criterion based on the accumulated pore pressure is applied in order to predict the onset of residual liquefaction. The results show that the pore pressure and shear stresses are in good agreement with the analytical results and the relative errors are less than three percent. Also, the numerical results indicate that the wave induced residual liquefaction originates from the mudline and progresses slowly down the soil which is consistent with the analytical results. The pore pressure buildup for a seabed with stone columns shows that the liquefaction potential is very low near the stone column.