A Finite Element Analysis of Migration of Landfill Gas in Unsaturated Soil

摘要

A two-dimensional, two-phase flow numerical model for the migration of gas in unsaturated soil was developed based on the finite element method employing the Galerkin discretisation technique. The governing system of non-linear partial deferential equations of the model was derived from a mechanistic approach. The model treated the migration of liquid water, heat, dry air, carbon dioxide and methane gases one by one with five-independent system variables of pore water pressure, temperature, pore air pressure and molar concentration of carbon dioxide and methane. The numerical results are compared against previously published experimental data.