煤岩体拉伸失稳破坏电荷感应规律研究

 为研究不同类型煤岩试样拉伸破坏过程自由电荷运移规律，以巴西圆盘劈裂试验为基础建立煤岩拉伸失稳破坏全程电荷监测系统。试验中分别对砂岩、泥岩及煤体拉伸失稳动态破坏过程进行实时电荷监测，得到煤岩体拉伸破坏过程中的力学特征和自由电荷运移规律。研究结果表明：煤岩体拉伸过程中有自由电荷产生，电荷信号异常区域对应于煤岩劈裂试验中应力突变阶段，煤体拉伸破坏所产生的自由电荷相对于砂岩、泥岩更为丰富，煤体断裂后的残余强度依旧使得电荷信号有较大波动，而砂岩、泥岩试样断裂后的残余强度却使得电荷信号波动较小。煤岩体拉伸与压缩破坏电荷感应规律不同，拉伸失稳破坏过程中拉应力造成裂纹扩展进而导致损伤局部化是电荷信号异常的重要原因之一。

STUDY OF CHARGE INDUCTION LAW OF COAL AND ROCK MASS DURING TENSILE INSTABILITY AND FAILURE

In order to study the free charge migration law of different types of coal and rock samples during the process of tensile failure，the charge monitoring system for coal and rock tensile instability and failure is developed under the frame of the Brazil disk splitting test. The mechanical characteristics and free charge migration law are obtained through the real-time monitoring process of sandstone，mudstone and coal samples during tensile instability and failure. The results show that there exist free charges during the tensile process of coal and rock mass. Charge signal abnormal area is corresponding to the stress mutation process in the samples splitting test；and the free charges produced by coal is richer than that produced by sandstone and mudstone during tensile failure. Compared with sandstone and mudstone，the residual strength of coal after fracture still makes the charge signal have larger fluctuation. Charge induction law is different between tensile and compression failure of coal and rock. One of the important reasons for the abnormal charge signal is the damage localization caused by crack propagation under the tensile stress during the tensile instability and failure of coal and rock mass.