预制裂纹岩板破坏电位与电磁辐射特征的实验研究

Experimental study of characteristics of surface potential and electromagnetic radiation of pre-cracked rock plate during fracture

为了研究预制裂纹岩板破坏电位和电磁辐射变化规律,对不同裂纹倾角花岗岩板进行了不同加载速率单轴压缩实验.结果表明:预制裂纹岩板电位和电磁辐射随载荷的变化而变化,破坏前出现电磁辐射能量峰值和一定的电位峰值,电位和电磁辐射能量增量与变化率一般会出现突变;电位变化幅度及其破坏前均值与距离主破裂的位置有关;预制裂纹倾角越大,载荷峰值越小,其出现时间越早,电磁辐射能量峰值越靠近载荷峰值,破坏前电磁辐射能量均值越低;加载速率越大,电磁辐射能量超前破坏时间越短.电磁辐射能量与电位增量、变化率、标准差、均值、变异系数可以作为研究煤岩破坏前兆特征的指标.

To study the variation of surface potential and electromagnetic radiation（EMR） dur- ing the fracture of pre-cracked granite rock plate, the uniaxial compression tests for samples with different pre-crack inclination under different loading rates were carried out. The results show that surface potential and EMR change with the load. Before failure there are EMR energy peak and certain surface potential peak, and the increment and change rate of surface potential and EMR energy will generally show sudden change. The change increment and pre-rupture mean of surface potential are related to the distances between main rupture and electrodes. With the increasing of pre-crack inclination, the load peak will be smaller, the time of load peak will be earlier, and the EMR energy peak will be closer to the load peak, the mean of EMR energy before rupture become smaller. The increase of the loading rate can shorten the time of the EMR energy peak ahead of the rupture. The increment, change rate, the mean, standard deviation and coefficient of variation of EMR energy and surface potential can be used as the indexes of the precursor to rock failure.