A coupled mathematical model for accumulation of wave-induced pore water pressure and its application

Abstract

Prediction of the wave-induced instability of seabed due to the build-up of pore water pressure is essential for coastal engineers involved in the foundation design of marine infrastructure. Most Previous studies have been limited to decoupled residual mechanism for the rise in excess pore water pressures. In this study, the existing decoupled approach has been improved to consider the coupling effect between the development of pore water pressures and evolution of seabed stresses. Comparisons with the existing wave flume tests and geotechnical centrifuge wave tests have demonstrated that the developed coupling approach is capable of reproducing the accumulation of pore water pressure under cyclic wave loadings, and shows more promising predictions compared to the existing decoupled model, especially for the case of standing waves. The validated framework is further extended to a field scale numerical model to investigate the development of pore water pressures and the corresponding liquefaction susceptibility of seabed to water waves. The numerical results have revealed the different mechanism for wave-induced pore pressure build-up in marine soils between the developed model and the existing decoupled model. The coupling effect of residual pore pressure and seabed stress could accelerate pore pressure accumulation, which implies that the existing decoupled model may underestimate the liquefaction potential of seabed, particularly under standing wave loadings. Furthermore, results of the developed model have shown that the effect of wave nonlinearity on advancing seabed liquefaction is more noticeable for progressive waves than that for standing waves.