Abstract
This paper employed the numerical procedure based on the lower bound theorem by introducing the contact condition along rock joint to clarify the mechanical property of joint strength. By simplifying the complicated real geometry of rock joint, the effect of triangle shape asperity on joint strength was investigated. The applicability of employed method was examined in comparison with both the experiments by Patton and the upper bound solutions by limit analysis. The failure mechanism of rock joint was shown to change with the increasing normal stress from the sliding failure along the asperity to the mixed failure of sliding along the asperity and shearing of asperity. It was found that the non-linearity in joint shear strength for normal stress was caused by the change in failure mechanism of rock joint.
