A numerical model for the electrokinetic treatment of natural soils with calcite

To the aim of verifying the feasibility of electrokinetic remediation, a laboratory investigation is being performed on samples of natural clayey soils. The experimental data collected highlighted sharp changes of pH, reduction of soil electrical conductivity, and fracturing close to the anode, which were interpreted as consequences of arising severe CO 2 pressures in the anode area accompanying calcite dissolution. A model for the analysis of the coupled electro-chemo-hydraulic processes, taking place during electrokinetic treatments of natural soils, is presented. The numerical model accounts for relevant processes, which are not adequately taken into account by existing models, namely gas generation and transport, and chemical equilibrium of calcite at varying pH. The implementation of the theoretical model in a FE code allows for analysing the evolution of the local constraint conditions imposed to the chemical system, and to model the transient response of the soil subjected to electrokinetic treatments. The results of the numerical simulation of a one-dimensional filtration test are presented and compared with selected experimental data coming from the laboratory investigation. © 2010 Taylor & Francis Group, London.