Shear strength of rock joints under constant normal loading conditions

The variation of shear strength of rock joints under constant normal loading conditions was studied. Three dimensional printing technology was incorporated to produce moulds of rock joints. Rock joints samples with three different roughness values were cast using concrete with uniaxial compressive strength of 20 MPa. Samples were sheared using a direct shear testing machine for normal stress values ranging from 0.25 to 0.7 MPa. In addition, effects of shear rate on shear strength properties of rock joints were experimentally investigated. It was found that the shear strength of rock joints is a function of normal stress, joint roughness and shear rate values. In addition, it was shown that three dimensional printing technology is a useful tool to replicate real rock joints.