利用自主研制的电荷感应仪,建立单轴压缩条件下煤岩电荷感应试验系统.研究了煤、花岗岩、砂岩在不同加载速率下的电荷感应规律.试验结果表明:煤岩电荷感应最大值在应力达到极限强度前出现,且随加载速率增加,电荷最大值比应力极限强度提前出现时间有减短趋势.不同性质煤岩体,电荷感应最大值有较大区别,花岗岩电荷最大值大于煤电荷最大值,煤电荷最大值大于砂岩电荷最大值.当应力较小时,煤岩只产生微量的电荷信号,当应力达到煤岩极限应力的90%左右时产生大量的电荷信号,说明煤岩电荷感应存在应力阈值.因此,电荷感应方法作为预测预报动力灾害是可行的,值得深入研究.
The coal rock charge induction test system under the condition of uniaxial compression is established by use of the self-developed charge induction instrument. And the charge induction laws under different loading rate of coal, granite, sandstone are researched. The experiment results show that the maximum value of coal rock charge induction appears before the stress reaches its peak, and with the increase of loading rate, the time of maximum charge value preceding the strength limit tends to be shorter. The maximum value of coal rock charge induction differs greatly among the coal rock of different properties. The maximum value of granite charge is greater than that of coal charge, and maximum value of coal charge is greater than that of sandstone. Weak charge signals are generated when the stress is small; when the stress reaches about 90% of the ultimate stress of coal rock a large amount of charge signals are generated, it illustrates that stress threshold exists in the coal rock charge induction. So the charge induction method is feasible for the forecast of dynamic disaster and it worth to be researched deeply.