Solute transport in partially-saturated deformable porous media: Application to a landfill clay liner

Based on the one-dimensional Biot consolidation equations, this paper developed an advection–diffusion equation that incorporates saturation, compressibility of the pore fluid and longitudinal dispersivity of the solute transport in an unsaturated, deforming porous medium. A simplified model was proposed for the case of a landfill liner. Numerical results demonstrated that the longitudinal dispersivity and compressibility of the pore fluid can be significant. Furthermore, the degree of soil saturation and loading rate of the waste surcharge affect significantly the contamination advective emission, namely the cumulative contaminant mass outflow per unit area from compacted clay liner (CCL) due to advective flow.

► New advection–diffusion equation with compressibility and longitudinal dispersivity.
► A simplified model for the application to a landfill clay liner.
► Dispersivity and compressibility affect significantly contamination advective emission.