颗粒煤岩破裂过程声发射与电荷感应试验

考虑颗粒间摩擦和黏结力作用，建立了基于颗粒物质力链失稳的煤岩体破裂判据。分析颗粒煤岩单轴压缩试验结果，得到了颗粒煤岩抗压强度、弹性模量随颗粒煤岩粒径增加而降低的变化规律，从细观尺度证明了煤岩单轴压缩张拉破坏的根源为剪切破坏。分级和循环2种加载试验研究结果表明：颗粒煤岩破裂过程中的声、电荷信号与力链中颗粒摩擦及粘结情况密切相关，声、电荷信号的产生机理存在本质上的差别。从破裂类型看，微裂隙的张拉破坏和颗粒摩擦错动均可导致声发射出现，而煤岩颗粒间的摩擦和微破裂面的相互错动是产生大量自由电荷、发生电荷感应现象的主要原因。可以利用声信号高-低-高的周期变化次数预测采动煤岩体经历的分级和循环加卸载次数；电荷信号首次突变-平稳-突变的出现时间是采动岩体应力阶段的划分标准。声、电荷信号幅值突变的剧烈程度是采动煤岩体失稳的重要前兆物理信息，可由此预测煤岩体稳定性，以便及时做出预警和相应的防护措施。

Experiment of acoustic emission and charge induction in granular coal rock failure

With the consideration of friction and adhesion，a coal rock fracture criterion was developed based on granular substance force chain instability.By analyzing the results of granular coal rock uniaxial compression，it was found that the compressive strength and elastic modulus of granular coal rock become lower with the increase of granular size，which verifies that the root of granular coal rock uniaxial compression tensile failure is shear failure in microscopic aspect.The study of uniaxial cyclic load and step stress shows that：acoustic emission and charge induction signals are closely related to the granular friction and adhesion in force chain and the mechanism of acoustic emission and charge induction signals have essential differences.From failure types，both tensile failure of micro-fracture and granular friction dislocation can cause acoustic emission and the friction of granular coal and the dislocation of micro-fracture face are the main reason of free electrons and charge induction.The authors can use the period frequencies of acoustic emission “High-low-high” signs to forecast the mining coal rock mass classification and cyclic loading and unloading times.The time of the first charge induction “mutation-smooth-mutation” signs is the standard for the division of mining coal rock mass stress stage.The severe level of acoustic emission and charge induction signals mutation is an important prognostic physical information of instability in mining coal rock mass，thus the authors can forecast the stability of coal rock mass，provide warning and take corresponding protective measures in time.