Numerical model for contaminant transport in consolidating sediments

A numerical model for coupled, one-dimensional, large strain consolidation and contaminant transport, called CCT1, is presented. The large strain consolidation algorithm includes all the capabilities of a previous code, CS2. The contaminant transport algorithm includes advection, dispersion, and linear equilibrium sorption with a spatially varying distribution coefficient. Advection-dispersion transport is consistent with spatial and temporal variations of porosity and seepage velocity in the consolidating layer. The key to the transport model is the definition of two Lagrangian columns of elements that follow the motions of the fluid and solid phases separately. Verification checks of CCT1 show excellent agreement with analytical solutions for classical transport problems involving advection, diffusion, dispersion, and sorption in rigid porous media. The performance of CCT1 is illustrated for an example problem involving consolidation-induced transport of a dilute contaminant species in a soft sediment layer.