ARMA 09-120 A Fully-Coupled Finite Element Code for Modeling Thermo-Hydro-Mechanical Processes in Porous Geological Media

摘要

This paper describes a new FEM code for modeling coupled thermo-hydro-mechanical processes in porous geological media. For three-dimensional problems, six governing equations, which are based on the conservation equations of momentum, mass, and energy, are presented to describe the coupled THM processes. The three displacement components, the temperature, the pore fluid pressure and the porosity are chosen as the six primary variables. The governing continuum equations are discretized in space by using the Galerkin finite element formulation, and are discretized in time by one-dimensional finite difference scheme. This leads to a large non-symmetric matrix equation that has many small entries along its diagonal, and is therefore ill-conditioned. For efficient equation solution, some special numerical techniques are used in the code in order to deal with the problem of a large non-symmetric ill-conditioned matrix equation. The code was validated against several classical analytical solutions to problems in poroelasticity and thermoelasticity, and tested against a benchmark laboratory experiment that was performed in the Polytechnic University of Catalonia (UPC), Spain.