Hydrodynamic characterization of water-transfer processes in slowly permeable, unsaturated, swelling porous media. Application to waste disposal sites

The hydrodynamical properties (in particular the permeability) of partially saturated deformable materials, have to be characterized to use them in wastes storage sites. These properties are examined according three approaches: analytical, experimental and numerical. The author proposes a simulation (adapted to the Darcy law) of the water transport in a flexible medium. In that case, the transfer equations bound the three functional relations: retention, hydraulic conductivity and inflating curved. The infiltration analysis in a saturated medium, allows to introduce the sorptiveness concept of the solid phase, complementary to the capillary sorptiveness. Experimental techniques are implementing to study, in a transient regime, the infiltration in compact materials natural (clay) and artificial (sand-bentonite compound). The observed phenomena are reproduced with the WISP code, that allows the key-factors study of the flow in a poor permeable medium. The results show that the capillarity takes the most important part of the transport. (A.L.B.)