Transport of contaminant or solute in saturated or unsaturated soils has been widely investigated in the literature. The soils are usually assumed to be rigid. However, there are cases where soils may be deformable and the deformation of the soils may influence the transport of contaminant. In this paper, a finite element model for contaminant transport in unsaturated deformable soils is established based on the governing equations of solute transport, flow and deformation in unsaturated soils. Transport of solute in a hypothetical landfill liner is used as an illustrative example. Numerical analyses are performed to investigate the transport of contaminant and the deformation of the unsaturated landfill clay liner. Effects of the soil compressibility, the level of water table, unsaturated hydraulic parameters are investigated in the parametric study. It is found that with a lower initial water level, the settlement at the surface at the clay liner is initially larger during the consolidation period and the breakthrough time of the liner is longer. However, the final settlement of the clay is smaller with a lower initial water level. If a soil is more compressible, the breakthrough time of solute transport is shorter. With the increase of saturated hydraulic conductivity, the settlement of clay increases and the breakthrough time decreases. With a larger α value, the final steady state dimensionless concentration at liner base is greater and the consolidation rate is larger during the consolidation period.

This content is only available via PDF.
You do not currently have access to this content.