Prediction of rock tensile-shear fracture propagation and crack interaction

Abstract

Abstract The interaction and influence between various rock cracks (unequal and noncolinear) are the root cause of fracture in natural rock bodies. In this study, to analyze the interaction law of such cracks, elastic mechanics and the principle of distributed dislocation were superimposed to calculate the mechanical parameters and expressions of the tip stress intensity factor (SIF) and equivalent SIF of two tensile-shear cracks subjected to far-field force. The effects of secondary crack characteristics on the interactions of SIFs at the main crack tip were theoretically analyzed. Then, a secondary crack inclination angle prediction model was established based on the PSO-LSTM theory. The calculated SIF was found to be consistent with the results of the classical Kachanov method and SIF handbook, which further verified the correctness of the derived expression. The results of this study can provide theoretical guidance for evaluating the stability of underground rock excavation projects.