组合煤岩冲击破坏电磁辐射规律研究

RESEARCH ON ELECTROMAGNETIC RADIATION RULES OF COMPOSED COAL-ROCK BURST FAILURE

大量理论研究和物理试验已经证实煤岩变形破裂过程中会产生宽频带的电磁辐射信号,因此研究坚硬顶板–煤体–底板所构成的组合煤岩变形破裂电磁辐射规律对于预测预报煤岩动力灾害具有重要的意义。采用MTS815伺服加载以及Disp–24声电测试系统对组合煤岩变形破裂所产生的电磁辐射及声发射信号进行了测定,试验结果表明,试样在发生冲击破坏前,电磁辐射强度呈小幅度上升的波动趋势,且冲击破坏前兆会产生突变;而声发射信号计数率在试样冲击破坏时将急剧增加并达到最大值,随后产生突降。电磁辐射与声发射信号峰值位置出现的时间并不同步,电磁辐射信号的最大值出现在试样变形破坏的峰后阶段,而声发射信号的最大值位置则出现在试样的峰值强度处。电磁辐射信号出现峰值时声发射相对较弱,且声发射信号出现峰值时其电磁辐射强度也相对较弱。依此规律,可以对冲击矿压的危险性进行正确地评价和预测预报。

It is known that wide frequent electromagnetic radiation（EMR） signals can be produced in the processes of deformation and failure of coal and rock by many theoretical researches and physical experiments. So, the EMR rules of deformation and failure of coal and rock body composed of hard roof, coal body and floor are important to predict and forecast the coal and rock dynamic calamity. The EMR and acoustic emissions（AE） phenomenon in the rock burst process are investigated by using the Disp-24 acoustic-electromagnetic system and MTS loading system in the laboratory. The results show that the intensity of EMR signals rises slowly before burst failure but increases suddenly when burst failure occurs. The counts of AE signals increase suddenly to maximum value before failure, and suddenly decline. During the period of impact rupture of combined samples, the time when signal peaks of EMR and AE appear are not synchronous, and the maximum EMR signals appear at stage after peak stress. However, the maximum AE signals appear at the peak stress. The AE signals are comparatively weak when EMR signals reach to peak values; and EMR signals are comparatively weak when the AE signals reach to maximum values. With the achieved rules, the danger of rock burst can be evaluated and forecasted.