Propriétés hydrauliques des fractures simples dans un milieu argileux: le cas de la station IRSN de Tournemire (France)
S Savoye, J Justo Cabrera, JM Matray
International Conference on Groundwater in Fractured Rocks - Prague - 15 au 19 septembre
Different studies carried out on the argillaceous IRSN Tournemire site showed the occurrence of several types of discontinuities (fault and fracture) at different scales. The hydraulic properties of these structures are investigated by conducting in situ hydraulic tests. In a first step, we focused on both single isolated fractures, mainly filled by calcite and water-producing fractures with geodic cavities. Transmissivities determined by pulse test on sealed fractures range from 1.2.10-13 m2.s-1 to 2.10-13 m2.s-1. The values are of the same order than that measured on an unfractured zone (matrix). The slug and pulse tests on the fractures with geodic cavities give a range of transmissivities from 1.10-10m2.s-1 to 4.10-10 m2.s-1. These results suggest that these discontinuities might correspond to a possible preferential pathway for fluid migration.