Experiments in a Representative Environment

Abstract : This chapter details the experiments in a representative environment and discusses the results obtained on a model material (mortar), and on sandstone. The permeability is measured on each specimen prior to mechanical testing and serves as a reference value in forthcoming comparisons. The ratio between permeability measured under medium confinement and without confinement is approximately equal to one order of magnitude. The variation of permeability due to electrohydraulic fracturing is much larger than that. Each specimen was scanned in an X-ray tomography facility prior to and after testing. Two sequences of tests have been carried out. In the first one, the mortar specimens were subjected to a single shock under a variable injected electrical energy, for each of the three confinement levels considered. In the second sequence, the specimens were subjected to repeated shocks with a constant injected energy.