薄煤层动静组合诱发冲击地压的机制

Mechanism of dynamic and static combined load inducing rock burst in thin coal seam

理论分析了动静组合诱发冲击地压的应力条件和能量转化过程,揭示了动静组合诱发冲击地压机制,数值计算分析了工作面应力分布特征与煤厚之间的关系,采用微震监测数据分析了卸压爆破产生的应力波传播规律,并分析研究了薄煤层动静载特征及诱发冲击地压过程。结果表明:薄煤层工作面应力集中程度较厚煤层高,峰值应力区距离煤壁较近,应力梯度较大;采动动载直接与高应力叠加,且开采导致的应力降以及单位体积煤体释放的弹性变形能远高于厚煤层,在动静组合作用下,薄煤层工作面易于达到动静组合诱发冲击地压的应力和能量条件,显著符合动静组合诱冲机制。最后基于动静载组合诱发薄煤层冲击地压的机制,探讨了薄煤层冲击地压防治原则和技术方法。

The stress condition and energy conversion of rock burst caused by dynamic and static combined load were theoretically analyzed. Accordingly the mechanism of rock burst induced by dynamic and static combined load was proposed. In addition,the stress features around the workface under different coal seam thicknesses were numerically studied. Subsequently,the transmitting law of stress wave caused by stress releasing blasting was analyzed using micro-seismic monitoring system. The dynamic and static combined load characteristics of thin coal seam and the rock burst induced were studied. The results show that the stress concentration at thin coal seam is much higher than that at thick one,and the peak stress zone is much close to coal wall,and the stress gradient is larger. As the dynamic load caused by mining directly acts on the high stress zone,and the stress drop caused by mining,and the elastic energy releasing density in volume is higher than that of thick one,as a result of the combined effects of stress and energy,the rock burst risk liability of thin coal seam mining work face is higher than that of thick one,and the rock burst mechanism ofthin coal seam obviously corresponds with that of dynamic and static combined load inducing. Based on the mechanism of rock burst caused by the interaction of dynamic and static load,the principles and technologies in controlling rock burst were developed for thin coal seam.