A Stabilised Finite Element Method For Modelling Fluid Flow And Contaminant Migration In Geosynthetics

A stabilised Petrov-Galerkin Laplace finite element method (SLFEM) for the modelling of flow and contaminant transport in multi-layered containment systems comprising a geosynthetic clay liner (GCL) is developed. The method determines the hydraulic regime as well as the time-dependent transport of contaminants in the system. It can accurately represent the sudden jump in Darcy velocities close to leaks in the geomembrane. It is implemented in the computer software, Soil Pollution Analysis System (SPAS) with an easy-to-use graphic interface. The coupled equations of flow and transport are first presented, as well as the SLFEM formulation. The main features of SPAS are described and a case study of the transport of trichloroethene in a single composite liner is analysed. Finally, the usefulness of SPAS and more generally concentration-based assessments of geosynthetic liners in 2D space is discussed.