Abstract
Discontinuities such as, joints, bedding planes, shale, zones of alteration or failure reduce the shear strength of the rock mass (Hoek & Brown, 1980) and (Barton, 1986). In general, this reduction of resistance affects the stability of excavations, located in a rocky massif. When a rock block enters a shear situation, there is a dilatancy in the direction perpendicular to the plane of th…