Investigation of impact rock burst induced by energy released from hard rock fractures

Overlying key strata are regarded as plane-strained beams sandwiched by the soft rock strata in the up and down directions, and are considered elastic media. Based on the theory of the elastic foundation beam, the distribution of energy accumulation and fracture positions before and after the fracture of overlying key strata are derived, and the energy release of fractures in each stratum is calculated. To investigate the impact damage to a roadway owing to the breaking of the key stratum, panel 5312 of Jining No. 3 coal mine is taken as an example. FLAC 3D software was applied to simulate a rock burst on the roadway when the seismic source was located at the overlying key strata and different energy was released. It is shown that the side of the roadway near the working face had a high concentration of vertical stress in the coal, and the dynamic load increment generated by the source broke the static load state and triggered the rock burst. After the burst damage, the decrease in the vertical stress in the coal explained the source of the kinetic energy. With a horizontal deformation velocity of the roadway's surrounding rocks of 1.5 m/s as the limit, the critical energy value for the burst failure caused by the fracture of each key stratum was determined.