Confining pressure effect on the permeability and mechanical behavior of sandstone under a certain pore water pressure condition

In geotechnical engineering, the mechanical behavior of rocks under various In-situ conditions (stress state including axial stress, confining pressure, pore water pressure) have always been an important topic. Therefore, pressure effect on permeability and different size sandstone samples a certain condition was studied. The sizes shows roughly same exponential de-creasing law with increase pressure. test, both loading Young?s modulus E+ unloading E- increased continuously increasing while Poisson's ratio m - decreased to value then remained almost constant.