A damage model for hard rock under stress-induced failure mode

This paper presents a damage model for hard rock under stress-induced failure. Damage initiation is first proposed based on the study of promoted strain energy and impeded strain energy to damage. Then, simplified damage constitutive law is formulated by assuming that the stress-strain relationship of the intact part conforms Hooke's law. Aimed at expressing the brittle-ductile transition of hard rock under the condition from low confining pressure to high confining pressure, a modified Mazars' damage evolution equation is proposed. The validation results indicate that the proposed model is in accordance with the test data.