Rock burst is a common mine disaster often accompanied with casualties and property damage. An effective and accurate method for predicting rock burst is necessary. This paper proposed a method for predicting rock burst on the basis of energy theory. Firstly, according to the laws of energy distribution in the front of coalface, the energy judgment coefficient Q is proposed, the energy is not released to the outside when Q<0, it means that the rock burst will not occurs, the energy is released to the outside when Q>0, it means that the rock burst may occur, the greater Q value is, the more energy is released to the outside when rock burst occurs. Secondly, based on the geological structure of erosion zone, the influence of the uniaxial compressive strength and pre-peak energy with the different of the height ratio, lithology, and dip angle are analyzed, it concluded that uniaxial compressive strength and pre-peak energy at the bottom of the erosion zone slope are greater and the uniaxial compressive strength and pre-peak energy at the edge of the erosion zone slope are smaller. Finally, taking the Xiaoyun Coal Mine as the engineering background, the energy judgment coefficient Q for predicting rock burst is applied. The results of the field observation are consistent with the results of the energy judgment coefficient Q. It indicates that this method can better predict the location and intensity of rock burst and provide a novel idea for preventing the occurrence of rock burst.
Coal measure strata are composed of multiple interbedding strata with different hardnesses. A sudden release of energy that was stored in surrounding rocks of tunnels may induce a rock burst; however, the specific strata in which the energy is accumulated cannot be accurately determined, thereby leading to ineffective prevention and management techniques for rock bursts. To address this problem, this study conducted axial loading tests on three different types of rock specimens (coal, gritstone and fine sandstone) and their composite specimens, and ascertained the energy accumulation rules of various components of the composites prior to a buckling failure. According to the results: for the coal-bearing binary composite specimens, the energy accumulated in coal occupied 88.5 %, 79.0 %, 71.4% and 79.6 % of the total energy accumulated in the specimens respectively; for the binary composite specimens composed of gritstone and fine sandstone, the energy accumulated in gritstone took up 61.2 % and 76.5 % of the total energy accumulated in the specimens respectively; and for the ternary composites, the energy accumulated in the coal occupied 79.8 %, 74.0 % and 76.3 % of the total energy accumulated in the specimens respectively, followed by the energy accumulated in the gritstone (12.1 %, 22.0 % and 18.8 %), and finally by the energy accumulated in the fine sandstone (only 8.1 %, 4.0 % and 4.9 %). Accordingly, in the composite rock strata, a small amount of energy was stored, and energy accumulation was more difficult in competent rock with large elastic moduli, while non-competent strata with small elastic moduli were preferable with regard to energy storage and accumulation. It can thus be concluded that the energy in coal-rock composites was accumulated mainly in non-competent strata, i.e., non-competent strata were key energy strata; additionally, the greater the difference in the hardness of the various components, the stronger the impact effect on the composite specimen.