Physical Simulation on Failure around a Circular Cavern in Hard and Brittle Rock under High and Increasing Natural Stress Conditions

AbstractTo analyze the dynamic failure process around a circular cavern in hard and brittle rock under high and increasing natural stress conditions, an 800×800×800-mm physical model with a ϕ 160-mm circular cavern in the center was produced by using the self-developed physical model material and tested in the self-developed model test machine under plane-strain conditions. From the physical simulation, when Px=Pz=600 kN (σX=σZ=3.75 MPa), shallow skinlike flakes appeared on the cavern wall, and large-scale abrupt failure occurred during a limited loading-zone for a short time until Px=Pz=630 kN (σX=σZ≤3.94 MPa). Then, a relatively steady state was followed by a long period with the load increasing. To understand the mechanical behavior around the circular cavern better, in the light of the physical simulation, a numerical simulation was also applied for comparative analysis. Both the numerical simulation and the physical simulation were consistent with each other, and they presented the same failure mechanism.