Vertical drain aided consolidation and solute transport

Abstract

Land and groundwater pollution is increasingly threatening public health and ecological safety. Vertical drain is recognised as an effective solution to clean up contaminated lands. Clean-ups often involve complicated hydro-chemical transport processes and are difficult to manage. This study presents a consolidation–solute transport model to assist with clean-up management. The model can predict coupled consolidation and chemical transport in diverse ground conditions, e.g., fully or partially saturated, less to highly deformable, or permeable to impermeable layers. To factor in the varied ground conditions, the model integrates the unsaturated flow characteristics, finite deformation theory and finite difference method into a set of governing equations and numerical solutions. The model was experimentally verified and then applied to examine effects of soil saturation conditions, solute transport conditions, and consolidation efforts on solute transport. The results show that the dispersion process contributes to the chemical clean-up, whereas the contribution becomes less noticeable in unsaturated conditions. The solute sorption process counteracts the solute transport and delays the clean-up. The consolidation accelerates the transport of reactive chemicals but shows limited effects on transport of non-reactive chemicals.