Void space against fracture hydro mechanical behavior at sample scale
Résumé
Results from laboratory experiments on natural fracture samples from the medium (roughly 20 m by 20 m by 20 m) sized superficial limestone bedrock reservoir, namely Coaraze natural site, France, is presented here. The BCR3D (3D direct shear box) with its hydraulic sectorized device, and its portable laser beam from 3S (Soils, Solids, Structures) Laboratory, France, was used. The interpretation of the cyclic hydro mechanical compression tests shows an apparent residual intrinsic transmissivity of Tr = 3 x 10(-15) m(3), the evolution of the intrinsic transmissivity versus the normal stress is anisotropic. The comparison of the fracture void spaces with hydro mechanical factors show that: the back computed method to obtain the void spaces is verified for low normal stress values, and the anisotropy of the outflow is explained by the modeled evolution of the void spaces with the normal stress. The Dunat (1996) law that depends on the contact surface could integrate a spatial distribution and damage factor and/or a plastic parameter.