| Coal and rock dynamic disasters, such as coal and gas outburst, seriously affect the safety production of coal mine, and threaten the safety of mine workers. With the increase of mining depth, the risk of coal and gas outburst is increasing and this occurrence become more complex. Therefore, real-time monitoring and early warning of coal and gas outburst is important to prevent outburst and to ensure safety production. For the problem during monitoring, e.g. A wide variety of interference sources, the undefined and difficult to identify precursor rule, low alarm accuracy, together with the single prediction index of outburst and discontinuous prediction in Yi Zhong mine working face, we take the 11112 heading face of Yi Zhong coalmine as the research object. The electromagnetic radiation, acoustic emission and gas were real-time monitored during roadway excavation process. The law and characteristics of interference signal in heading face was analyzed and the avoidance method was put forward. The response law of electromagnetic radiation, acoustic mission and gas density for gas pre-pumped and outburst and other working procedures was researched. Single indicator warning threshold was determined in accordance with the precursory law and in-situ test data, and the real-time monitoring and comprehensive early warning system of Yi Zhong mine coal and gas outburst was established on the basis of projection pursuit method for confirming the thresholds of comprehensive early warning indicators. Yi Zhong mine comprehensive early warning system was verified according to the actual monitoring data.This main research results are as follows:(1) Installed a electromagnetic radiation-acoustic emission-gas monitoring system in 11112 heading face of Yi Zhong. Electromagnetic radiation, acoustic emission and gas density were monitored during roadway excavation.(2) The interferences signal of acoustic emission and electromagnetic radiation in heading face were analyzed, the characteristics of the interference signal was distinguish, the avoidance method of interference signal was put forward..(3) The response law of acoustic emission and electromagnetic radiation and gas in heading face of Yi Zhong mine were revealed: there is a good correspondence between the signal of electromagnetic radiation, acoustic emission and the procedure of blasting, tunneling speed and gas pre-drainage. Using multiple time scale method, we analyze the electromagnetic radiation, acoustic emission and gas signal in response to emerging hazards of outburst and other dynamical phenomena, and found two precursory law of outburst. The index of acoustic emission, electromagnetic radiation and gas share a high correlation with K1(conventional indicators),but they were less relevant with S.(4) The overrun, trend, volatility early warning indicators were proposed and its thresholds were determined by using the method of fuzzy mathematics. A comprehensive warning indicator was established by using the projection pursuit method, and the comprehensive monitoring and early warning of coal and gas outburst were achieved.(5) Comprehensive early warning method was verified by Yi Zhong mine real-time monitoring data, the results of comprehensive early warning corresponded well to fault zone, abnormal gas emission, trend abnormal of conventional indicators, gas-jet, pushing-drill and other events, so the method can effectively improve the timeliness and accuracy of outburst warning. |
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