Abstract:In order to discuss rockburst process and mechanism in the surrounding rock of a circular cavern,a physical model,which is 800 mm long,800 mm wide and 200 mm thick with a f 160 mm circular cavern,is produced with hard brittle physical model material from orthogonal experiments by the generalized indexes of uniaxial compressive strength( ),brittleness coefficient(K) and exponential of impact energy( ). The physical model is tested in the large true triaxial model-test machine in geotechnical engineering under the plane strain condition. There are some test results as follows. The peak value of the -( ) curve moves backwards;and the shape of the -( ) curve is not metabolic if the state of the surrounding rock changes from elasticity to plasticity during the process of the horizontal load( ) and the vertical load( ) being kept equal and being loaded in phase. On the other hand,flake like shallot skin comes into being in the cavern wall when and loaded in phase are all 600 kN,then large-scale paroxysmal breakage occurs in the surrounding rock during a short time and a limited loading-zone when and loaded in phase are equal to 630 kN. Subsequently,a relatively steady period appears in a relatively long time and a relatively broad loading-zone,following stress adjustability,if and are loaded in phase sequentially.