A new peak shear strength criterion based on morphological characteristics for natural rock joints

As a result of different stages of geological processes, joints are created with various surfaces and degrees of matching. However, some researchers have studied the shear mechanism of rock joints in the laboratory; most works have been carried out on mated joints with regular shapes (square or rectangular). The study of shear behavior of natural joints obtained from core drilling with different morphological characteristics, degrees of matching, and irregularly shaped is an issue that has gained less attention. In this study, the morphological characteristics of 37 natural rock joints by photogrammetry. A new three-dimensional mobilized roughness was presented with the analysis of the shear-measured results based on the morphological parameters and the least square fitting method. A model was developed to predict the shear resistance of natural rock joints. Finally, the estimation accuracy of the available classic models was compared with the new model, and it was observed that the new criterion could predict more accurate results.