Failure mechanism and stability analysis of an open-pit slope under excavation unloading conditions

Excavation unloading significantly contributes to rock slope failure in an open-pit mine. At present, there is no relevant theoretical study on the mechanism of under excavation unloading. Therefore, this study, based theory fracture mechanics, expression stress intensity factor at crack tip mass vertical distance, h, from top derived, calculation method initiation angle given, ultimate safe height obtained, and ratio toughness composite defined as stability factor, which verified by engineering example. The results show that decreased when inclination was increased, increased side-pressure coefficient, angle, friction coefficient were increased. safety first then with increase it approximately linear length inversely proportional angle. calculated same limit equilibrium small, indicates accuracy rationality method. Results can provide a basis for understanding controlling collapse disaster induced