Danger-relief principle and parameter optimization of borehole energy relief for rock burst in coal road floor

The mine area located in northwest of China is seriously affected by horizontal tectonic stress. The borehole is widely used to control coal burst and is an effective, convenient and safe measure. The scientific and rational formulation of borehole parameters can effectively improve the efficiency of coal burst hazard prevention and controlling, but at present there is still a relatively lack of pertinent research. For this reason, based on the mechanical model of floor failure, this paper studies the principle of energy release and relief of floor drilling, establishes a FLAC^3D numerical model to study the reasonable value ranges of different drilling parameters, and conducts on-site industrial application demonstration. Research results show that: ①It’s an effective measure to prevent the floor coal burst by releasing elastic deformation energy accumulated in coal and its energy storage condition and the “lader” structure transfer horizontal stress to deep strata. ②The degree of horizontal stress reduction in the bottom plate is approximately positively correlated with the inclination of the borehole. Implementing the bottom plate pressure relief drilling angle of 60°-75° can achieve a better bottom plate pressure relief effect; The reasonable range of drilling spacing is between 1-3 m, which can have an ideal effect on the prevention and control of impact ground pressure on the entire bottom plate; As the diameter of the hole increases, the degree of stress reduction in the central area of the bottom plate increases, and the diameter of the drill hole implemented on site should be 140-200 mm; The ideal drilling row spacing arrangement should be 1.4-1.8 m, not the smaller the better. ③The research results were applied to a mine in Binchang mining area, and the anti-scouring efficiency of coal seam floor was verified, it effectively controls the degree of the kick drum and the intensity of the impact hazard, the effectiveness of the measures to relieve the danger and the erosion of the bottom plate and the rationality of the drilling parameters are verified.