ABSTRACT
This paper presents the first results of the hydromechanical stimulation of a jointed rock mass that was submitted to a controlled hydrostatic pressure. Under water pressures of about 0.7 bars, the behaviour of the rock mass is elastic and the deformation is localized along joints. For a pressure lower than the lithostatic one, deformation correlates with the permeability of joints: the most permeable joints open and this opening induces the closing of the least permeable joints. For a pressure in the range of the lithostatic pressure, the tilting of blocks amplifies the deformation.
