Fracture of granite under various strain conditions

Mechanisms of fracture of granite specimens subjected to loading controlled by the defect formation rate are studied in the experiments on stick-slip initiation and deformation of water-saturated specimens from the acoustic emission measurements. It is found that under mechanical loading of dry specimens, the initially dispersed formation of defects is followed by the stage of their localization, and then a fracture nucleates whose development results in the formation of macrofracture and failure of the specimen. In water-saturated specimens, multiple defects are formed randomly throughout the entire volume, which causes intense damage to the material. At the final stage of deformation, several source regions appear in which the main cracks develop. If fracturing follows the stick-slip scenario, the stoppers located on the sides of the fault are destroyed.