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.

Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

“…The paper is organised as follows: Section 2 outlines the theoretical model, including the oscillatory and residual seabed models and the coupling process, which is established within OpenFOAM. Section 3 validates the present model by comparing it with previous experimental data and the decoupled model [18]. Section 4 presents a detailed discussion of both mechanisms based on the present model.…”

“…Note that the third term on the left-hand-side of ( 18) is an additional term comes from the u − p approximation, which was not included in the previous residual model [4,18,31].…”

“…Equations ( 5) and (9) together with (18) are the governing equations of the partially dynamic (u − p) residual mechanism. With appropriate boundary conditions, the waveinduced soil response can be obtained by solving the above governing equations with appropriate boundary conditions.…”

“…Previous studies on wave-induced residual liquefaction were based on Biot's consolidation model, a quasi-static approach that neglects accelerations caused by soil and fluid particles [13][14][15][16][17][18]. However, soil and fluid particle accelerations are critical under specific combinations of wave and seabed conditions [19,20], which are not considered in the decoupled approach used in previous studies.…”

A Review on the Modelling of Wave-Structure Interactions Based on OpenFOAM

“…Elsafti and Oumeraci [158] implemented a multi-yield surface plasticity model to simulate plastic soil response under cyclic loads in their CFD solver geotechFoam, also developed in the OpenFOAM framework. A recent work from Shanmugasundaram et al [159] has presented a new development to calculate stress fields in seabed, which is capable of predicting residual-liquefaction problems.…”