Coupled problems in partially saturated multiphase porous media and F.E. PLASCON3D code validation

The F.E. code PLASCON3D is based on partially saturated porous media theory described in and it is a generalization of the fully saturated 2D and 3D versions of F.E. code PLASCON. The code develops coupled thermo-hydro-mechanical compaction/subsidence analyses within a partially saturated porous medium subjected to external loads and water/gas withdrawals from deep layers (aquifers/reservoirs). The code is also updated to take into account material non - linearities (critical state plasticity models), necessary once rebound phenomena are to be considered. It is planned to further extend the elasto - plastic constitutive law to partially saturated states by means of the BSZ model. In addition to the assumption of small strains and absence of inertial effects, the following simplifications have been introduced: - creep is not accounted for; - body forces and hydraulic heads are assumed to remain constant and act in the direction of one of the global coordinates; - the permeability matrix is assumed to have zero off-diagonal terms and it is assumed constant throughout each element. The program solves 3D problems and contains a single element type, the 20-noded isoparametric element; it has already been demonstrated that this element is sufficiently versatile to handle many situations in soil consolidation.