Early warning of coal dynamic disaster by precursor of AE and EMR"quiet period"

Efcient and accurate monitoring and early warning of coal dynamic disaster and other disasters can provide guarantee for the efcient operation of mine transportation system.However,the traditional threshold early warning method often fails to warning some accidents.To address above issues,a new early warning method was proposed based on"quiet period"phenomenon of AE and EMR during fracture.It is found that,a"quiet period"of AE and EMR was present before the load reaches the peak stress,which could be used as one of the precursors to warn the imminent failure of coal and rock specimens.MS and AE signals increased abnormally followed by the phenomenon of"quiet period"before the occurrence of coal dynamic disaster on site,and the decrease of MS events in the"quiet period"is about 57%–88%compared with that in previous abnormal increase stage.During the damage evolution of coal and rock,"quiet period"phenomenon usually occurred at 85%–90%of the peak stress,where the slope of damage parameter curve is almost zero.The"quiet period"of the AE-EMR signals and the low change rate of damage parameter before failure provide a theoretical foundation for the coal dynamic disaster warning based on the"quiet period"precursor found in MS-AE-EMR monitoring system.These fndings will help reduce the number of under-reported events and improve early warning accuracy.

掘进工作面煤与瓦斯突出前兆特征及综合预警研究

针对煤矿现行的煤与瓦斯突出静态预警方法预警指标单一且不连续,动态预警方法采用的临界值法容易产生误报等问题,通过分析金佳煤矿11227运输巷动力显现事件的前兆特征,提出了趋势预警方法作为声发射强度、电磁辐射强度、瓦斯浓度等指标预警的方法,并确定了声发射强度、电磁辐射强度、瓦斯浓度各指标趋势预警相关参数的临界值。在此基础上根据声发射强度、电磁辐射强度、瓦斯浓度指标预警结果,利用层次分析法确定了各指标权重,提出了声电瓦斯综合预警准则。通过现场应用及分析,结果表明:声电瓦斯综合预警方法可对掘进工作面突出危险性进行连续实时监测预警,综合预警准确率为92.7%,漏报率为0,误报率为7.3%,预警可靠性高,对防治煤与瓦斯突出保障安全生产具有重要的指导意义。