Numerical simulation of the wave-driven solute transport in deformable seabed

The process of solute transport into marine sediments from overlying water can be accelerated by waves. However, the effect of wave-induced deformation of seabed on solute transport has been ignored in most investigations. In response this paper investigates the influence of sandy bed deformation on the mechanism of solute transport using a modified solution-transport numerical model, in which the process of solute transport into deformable marine sediments from overlying water could be simulated under progressive waves. The results have shown that the seabed deformation will increase the velocity of pore water, which in turn increases the vertical hydrodynamic dispersion coefficient and the mechanical dispersion of solute transport. Therefore, the wave-induced deformation of soil will advance the process of solute migration into marine sediments. Case studies have indicated that in deformable soil the maximum vertical hydrodynamic dispersion coefficient could be 8.5 times that ignoring soil deformation, and about 545 times the molecular diffusion coefficient. The smaller the shear modulus of seabed soil, the more obvious soil deformation occurs, and the greater the influence of soil deformation has on solute transport. Furthermore, the reduction of degree of saturation will advance the solute transport into marine sediments.