冲击矿压危险预测的电磁辐射原理

Monitoring rock burst by electromagnetic emission

由于煤岩冲击破裂过程中,裂缝的形成和颗粒的摩擦会产生电磁辐射,因此,可采用电磁辐射技术来预测煤矿的冲击矿压危险.研究表明,电磁辐射基本上随着加载及变形速率的增加而增强;在发生冲击性破坏以前,电磁辐射强度一般在某个值以下,而在冲击破坏时,电磁辐射强度突然增加;煤体应力越大,变形破裂越强烈,电磁辐射信号也越强.煤岩变形破坏的弹塑脆性模型分析表明,煤岩体的损伤速度与电磁辐射脉冲数、声发射事件数成正比,与瞬间释放的能量、变形速度成正比.对具有强冲击危险工作面进行的研究表明,电磁辐射完全可以预测煤矿冲击矿压危险,检验卸压爆破效果,而且准确率高,效果明显.

The Electromagnetic Emission (EME) will be formed because of the formation of cracks and the friction between granules during rock and coal's burst failure. So, EME can be applied to forecast the rock burst in coal mine. Studies show that EME usually becomes stronger with the increase of load and the rate of deformation. EME amplitude is usually below a certain value before the burst failure, while it suddenly increases during the burst failure of the loaded coal specimen. The analysis of elasticity, plasticity, and brittleness model shows that the damage speed of coal and rock is in direct proportion to the EME impulse, the number of acoustic emission (AE), the instant released energy, and the deformation speed. According to the study of the working face with a strong probability of rock burst, the EME can be used to forecast the rock burst and to check the effect of unloading blasting in coal mine.