| It is proposed that the stiffness ratio between the environmental rock mass and bursting rock mass is the key factor influencing the strain burst, which is the unstable failure of the engineering rock mass system under the specific stiffness ratios. A series of strain burst tests have been conducted in the laboratory strain burst test system in which the specimen can be unloaded abruptly from the true triaxial stress state, and the rock mass stiffness effect on strain burst has been analyzed by considering different stiffness ratios resulted from the different rock types, different environmental rock mass and different structural planes; Based on Particle Flow Code (PFC), numerical strain burst analytical model considering the stiffness ratios has been built by programming with FISH embedded in PFC. The strain burst modes and energy release characteristics under different stiffness ratios have been compared and analyzed systematically in a series of numerical analyses. In addition, the rock mass with different orientated single set of discontinuities, double sets of symmetircal and asymmetrical discontinuities, and the discontinuities with different cohesion, friction coefficients, spacings has been considered in the numerical strain burst analyses, and the rock mass stiffness effect on the strain burst modes and energy release charactreisitcs have been analyzed. |
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