ANALYTICAL SOLUTION FOR CRITICAL ROCKBURST OF A CIRCULAR CHAMBER SUBJECTED TO HIGH IN-SITU STRESS

Based on the unified strength theory and a plastic strain damage model, the elastic-plastic analysis for a circular chamber subjected to high in-situ stress is conducted, by taking intermediate principal stress and shear dilation into account. The analytical solution for critical rockburst of a circular chamber is obtained by using the disturbance instability theory of rockburst. The results of the proposed analytical solution derived in this paper are found in good agreement with the results of the model experiment and the engineering observed cases. The influences of the unified strength theory parameter, shear dilation parameter, support pressure, ratio of up modulus to down, and internal friction angle on the critical rockburst are discussed. It is shown that the effects of intermediate principal stress and shear dilation can not be neglected when calculating the critical rockburst of a circular chamber subjected to high in-situ stress.