型煤受载破坏表面电荷和微震响应特征及相关性分析
Analysis of surface transient charge and the interdependent response of microseismic signal during the deformation of coal
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摘要: 利用自制的煤体表面瞬变电荷与微震信号测试实验系统,对型煤试样在单轴压缩破坏过 程中的应力变化、瞬变电荷、微震信号进行了监测和分析。 实验结果表明:在单轴压缩破坏过程 中型煤试样表面会产生瞬变电荷,电荷信号呈瞬时、单脉冲变化,持续时间较长,为5~12s;微震 信号则呈现出较为明显的阵发性,持续时间较短,为0.2~0.4s。 表面瞬变电荷和微震信号与应 力变化关联性较强,其总体变化趋势在时间尺度上具有较高的同步性,两者峰值时间差为0.08~ 0.5s。 试样破坏过程中存在一个能量释放临界点,对应于应力突变时刻,利用表面瞬变电荷和微 震信号时间尺度上的一致性及能量释放临界点特征,可对煤岩体失稳破裂过程进行更准确的预 测和分析。Abstract: Thestresschanges,transientchargesandmicroseismicsignalsofbriquettesamplesduring uniaxialcompressionfailureweremonitoredandanalyzedbyusingtheself-madeexperimentalsystem formeasuringtransientchargesandmicroseismicsignalsonthesurfaceofbriquette.Theexperimental resultsshowthatthesurfaceofbriquettesamplewillproducetransientchargeduringuniaxialcompression failure,and the charge signal changes instantaneously and monopulse,and lasts for a long time,about5~12s.However,themicroseismicsignalsshowobviousparoxysmaloccurrencewithashort durationofabout0.2~0.4s.Surfacetransientchargesandmicroseismicsignalsarestronglycorrelated withstresschanges,andtheiroveralltrendofchangehasahighsynchronizationintimescale.Thetime differencebetweenthepeakvaluesofthetwosignalsisabout0.08~0.5s.Thereisacriticalpointof energyrelease in the process of sample failure,which corresponds to the time of sudden stress change.Byusingthetimescaleconsistencyofsurfacetransientchargeandmicroseismicsignalandthe characteristicsofthecriticalpointofenergyrelease,theprocessofcoalandrockmassfailurecanbe predictedandanalyzedmoreaccurately.
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