Model tests on deformation and failure laws in excavation of deep rock mass with multiple fracture sets

The stability of surrounding rock of underground caverns in development of deep resources must face deformation and failure problems of post-peak fractured rock. At present, the deformation and failure laws of the surrounding rock of deep fractured rock mass in strong unloading excavation are unclear, often leading to large volume collapse, large deformation and other major engineering accidents. Using a large scale three-dimensional similar model test system, the deformation and failure laws in excavation of deep rock mass with multiple fracture sets and certain tilt angle under high ground stress are analyzed. The results show that the surrounding rock at the upper and lower sides mainly presents large deformation phenomenon, the rock at the left and right sides exhibits layered fracture phenomenon, and the fracture area increases from the inside to the outside with time. Large volume of side wall collapse is induced by the large deformation of vault and floor. The displacements and stresses of the surrounding rock from the inside to the outside are fluctuant. There is a great correlation between the fracture angle and the distribution of failure zone. The results may provide more experimental data for ensuring the safety of construction and operation of deep under-ground engineering.