煤与瓦斯复合体受载变形破坏特征及微震-电荷感应规律

Deformation and failure characteristics and microseismic-charge induction rules of coal and gas complex under loading

  • 摘要: 针对冲击地压-煤与瓦斯突出复合动力灾害预测手段欠缺、前兆信息监测方法不完善这一工程现状,利用自主研发的高频微震全波形实时监测系统和电荷感应监测系统开展了煤与瓦斯复合体受载变形破坏试验,分析了不同瓦斯压力下煤与瓦斯复合体变形破坏特征及微震信号和电荷感应信号显现规律的关系,以及瓦斯压力对3者的影响。 结果表明:煤与瓦斯复合体变形破坏可分为3个阶段,即弹性阶段、屈服强化阶段和破坏阶段,随着瓦斯压力的增大,煤与瓦斯复合体的抗压强度、弹性模量和软化模量减小,冲击倾向性降低,弹性和屈服强化阶段持续时间缩短;煤与瓦斯复合体变形破坏过程中有微震信号和电荷感应信号产生,且两种信号的峰值振幅均出现在煤与瓦斯复合体的破坏阶段;随着瓦斯压力的增大,微震信号和电荷感应信号数量增加且越来越分散,振幅增大,峰值振幅对应的应力降速率增大,同时,微震信号峰值振幅所在波形的起始振幅增大,峰值振幅前移,且越来越接近起始振幅。 煤与瓦斯复合体中瓦斯压力越大,越容易发生冲击地压-煤与瓦斯突出复合动力灾害,通过微震信号和电荷感应信号的监测能够在一定程度上判断复合体所处的变形破坏阶段,结合瓦斯压力大小可预判复合动力灾害的类型和危险性。

     

    Abstract: In view of the current situation that the prediction means on the composite dynamic disasters of rockburst-coal and gas outburst are limited and the monitoring method of precursory information is not sufficient,the deformation and failure monitoring test of coal and gas complex under loading was carried out by using a high-frequency micro-seismic full waveform real-time monitoring system and a charge induction monitoring system with independent research and de- velopment. The relationship between the deformation and failure characteristics of coal and gas complex and the rules of micro-seismic signals and charge induction signals under different gas pressures was analyzed. Also,the influence of gas pressure on them was analyzed. The results show that the deformation and failure of coal and gas complex can be divided into three stages:elasticity stage,yield and strengthening stage,and failure stage. With the increase of gas pressure in coal and gas complex,the compressive strength,elastic modulus and softening modulus of coal and gas complex de- crease,the bursting tendency reduces,the duration of elastic and yield strengthening stage shortens. There are microseis- mic signals and charge induction signals generated in the deformation and failure process of coal and gas complex,and the peak amplitudes of two signals both appear in the failure stage of coal and gas complex. With the increase of gas pressure,the number of microseismic signals and charge induction signals increases,the signals become more and more dispersed,the amplitudes increase,the stress drop rate corresponding to peak amplitude increases. At the same time,the initial amplitude of microseismic signal waveform containing peak amplitude increases,the peak amplitude moves for- ward,and more and more closes to the initial amplitude. The higher the gas pressure in coal and gas complex is,the easi- er the rockburst-coal and gas outburst composite dynamic disaster is to occur. The deformation and failure stage of com- plex can be estimated through monitoring of microseismic signals and charge induction signals to a certain extent,and in combination with the gas pressure,the type and hazard of composite dynamic disasters can be estimated.

     

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