A comprehensive peak shear strength criterion for rock joints

The basic principles of a new simple peak shear strength criterion for rock joints based on well-documented theory of friction and deformation of rough surfaces are presented. According to this criterion, the peak shear strength of a rock joint at any normal stress is interpreted as comprising two components, one purely frictional and one geometrical. The first is due to the shear strength of rock junctions sheared under high normal stress and is independent of roughness and scale. The second is due to surface roughness which causes dilation. Under a given normal stress, the joint is first deformed and then sheared along an inclined plane defined by the deformed asperities. The magnitude of the frictional…