Experimental Investigation on Engineering Disaster Simulation of Deep Buried Cavern Under Impact Load

Mining, drilling, blast excavation and large-scale explosive disturbance effects can all threaten the safety of constructed tunnels. Aiming to clarify the failure mechanism of deep-buried cavern under dynamic disturbance, a true triaxial deep cavern ground impact effect simulation test device was used to realize the whole process from cavern excavation to engineering disaster induced by impact load. Based on the similarity theory, similarity indexes of the whole model test were obtained. Cubic specimens of 1.3 m were used to simulate the failure process of the cavern with the length similarity ratio of 50:1. The test adopted sequence of loading, cavern excavation and plane impact disturbance. Dynamic and static pressure sensors, fiber Bragg grating sensors and dynamic displacement meters were used to monitor the changes of stress, strain and displacement. Evolution laws of stress and strain during the excavation and impact process were obtained. During the test, plane dynamic and static coupling loading were applied on the top of specimen. Results showed that with the increase of impact disturbance, the displacement and strain of surrounding rock increase, and so did the failure of cavern. The attenuation law of stress wave in the structure with cavity was obtained by analyzing the stress variation from the top to the bottom of the specimen. In addition, block activation was detected during the test. Finally, engineering disasters were simulated successfully. Findings are helpful for improving understanding of the mechanism of deep cavern disaster under dynamic disturbance.