考虑上覆岩层压力的深部岩体块系介质超低摩擦效应理论分析

Theoretical analysis of ultra-low friction effect in deep block rock mass considering overlying rock pressure

深部开采条件下,岩体块系介质超低摩擦效应与深部岩体动力灾害密切相关。基于我国矿山深部开采的实际情况,建立了法向荷载冲击作用下,考虑上覆岩层压力的深部岩体块系介质模型,理论推导了含岩层深度参数h的块体运动函数和位移时间函数的解析表达式,据此给出了地下800m煤系地层,岩体超低摩擦效应发生的最大载荷降速率为1.06×105N/s,岩体法向荷载波动周期为0.1 s。研究结果表明:随着岩体法向荷载的显著波动,岩体相对压紧程度趋于减弱,岩体超低摩擦效应易于触发,载荷降速率急剧增大,这可以作为岩体超低摩擦效应的重要表征指标之一。

Under the condition of deep mining, ultra-low friction effect in deep block rock mass is related with dynamic disaster in deep rock mass. Based on practical situation of deep mining in China, the model of deep block rock mass under normal impact load action and considering overlying rock mass pressure was established. The analytical expression of relationship between block kinetic function and displacement-time function was derived and the relationship involves rock depth parameter h. Based on this, it is deduced that the maximum load drop rate is 1.06 ~ 105 N/s when uhr-low friction effect generates at - 800 m coal and rock mass, and the fluctuation period of normal load in rock mass is O. 1 s. The results show that, with the obvious fluctuation of normal load in rock mass, relative blocks compaction tends to weaken, the ultra-low friction effect is easy to be triggered, and the load drop rate sharply increase. This can be one of the characteristic indices of the ultra-low friction effects in rock mass.