Study On Simulation Test Of Coal And Gas Outburst Induced By Deep Rock Cross-cut Coal Uncovering

Coal and gas outburst is one of the most serious dynamic disasters in the process of coal mining.Coal and gas outburst induced by rock cross-cut coal uncovering is of high risk and high intensity.As coal mines enter deep mining,low-index and low-parameter outburst occurs from time to time,and its precursory variation is not clear,which restricts the reliability and effectiveness of disaster early warning.The experimental method is one of the three main methods of scientific research.In this paper,a self-developed true triaxial coal and gas outburst simulation test system is used to simulate coal and gas outburst induced by deep rock-gate uncovering,taking coal samples from outburst coal seam in Hongyang No.3 Coal Mine as the research object.Based on acoustic emission monitoring technology,the whole process monitoring of coal dynamic damage.Combining with gas pressure and acoustic emission signal parameters,the precursory information and outburst risk index of coal and gas outburst are put forward.The purpose is to provide scientific reference for effective prediction and early warning of coal and gas outburst.The results show that the dynamic disaster phenomenon of coal and gas outburst is successfully reproduced in the experiment,and the characteristics of deep coal and gas outburst and the change trend of outburst precursor information in shallow part are obviously different.Relative outburst strength,critical gas pressure and other outburst characteristic parameters show periodic variation in different buried depth intervals.Therefore,a new method is proposed to improve the accuracy and validity of outburst prediction by establishing specific outburst risk indicators for different buried depth intervals and predicting outburst dynamic disasters in different zones.As one of the main influencing factors of coal and gas outburst,gas pressure has two typical characteristics in the process of outburst.In the process of outburst incubation,gas pressure has the characteristics of self-increasing characteristics,and in the process of outburst stimulation,it has the characteristics of stage and instantaneous change.Gas pressure not only provides the throwing kinetic energy of outburst coal body,but also accelerates the destruction of coal body by gas adsorption and desorption characteristics during outburst incubation process.Based on the variation rule of AE intensity per unit time,the outburst risk index N₁ is established,and the risk range of N₁ is established according to different burial depth,in-situ stress and effective stress interval.Based on the dual parameters of gas pressure and acoustic emission intensity,the outburst risk index N₂ is established.