Experimental Simulation of Explosive Impact Disturbance Induced Damage of Surrounding Rock Containing Structural Surfaces

Abstract:

In order to investigate the mechanism of the effect of ground impact disturbance generated by the blast action in the remote zone on the damage of deeply buried caverns， a similar simulation test was conducted using a ground impact effect simulation test device. A cube specimen with its side length of 1.3 m was used to simulate the entire process from ground stress loading （1 000 m burial depth）， cavern excavation to blast ground impact disturbance loading. During the test， sensors were placed inside the specimen and the cavern to monitor the change of stress， strain， displacement and damage inside the cavern. Damage phenomena such as debris crumbling out， fracture connectivity leading to block crumbling out， block slip and fault activation were reproduced by applying impact disturbance loads with different peak values on top of the specimen. Ultimately， preliminary safety thresholds for deeply buried cavern chambers were obtained. The damage mechanisms of fractured， block and fault-bearing rocks under different ground impact disturbances were obtained. Tests have proven that smaller dynamic disturbances can induce damage in deeply buried cavities. Moreover， the degree of chamber damage increases with the number of impact perturbations and the peak of impact load. The test results demonstrate that ground shock disturbances in the distant area of the explosion can still induce engineering hazards.