Peak shear strength criterion for mismatched rock joints: Revisiting JRC-JMC criterion

Rock joints with different matching conditions are widely existing in nature. The safety of engineering structure is significantly affected by the peak shear strength of mismatched rock joints; however, the available criteria do not work well for evaluating the peak shear strength of mismatched rock joints. In this study, the mismatched rock-like joints are first simulated by imposing various lateral dislocations along the shear direction, and then a series of direct shear tests are performed to investigate the influence of lateral dislocation on the peak shear strength. Experimental results show that the peak shear strength decreases with the increase in the lateral dislocation, even the specimens have identical single surface morphology. An empirical peak shear strength criterion with the inclusion of normalized lateral dislocation is developed to evaluate the peak shear strength of mismatched rock joint, which is further validated by tri-angular rock-like joints with various openings and natural mismatched rock joints. Compared to the available criterion in the literature, the developed one is in line with the achieved experimental results better. Finally, the limitations of the developed criterion are preliminarily discussed.