深部条件下的煤岩钻孔喷孔试验研究

摘要

In order to study the characteristics of dynamic behavior of coal and rock mass under deep conditions,the borehole blowout experiments under different loads were carried out by using an experimental system of borehole blowout,and the parameters such as stress,strain,drill cuttings quantity and acoustic emission of coal specimens were tested and analyzed.The results showed that the borehole blowout would occur only when the loading pressure exceeded a critical value.The larger the loading pressure,the larger the drill cuttings quantity,and the greater the number of borehole blowout.Meanwhile,the larger coal and rock particles ejected in the borehole blowout,which was a process of instantaneous release of energy,and the lateral stress and strain would undergo a process of sudden decrease or sudden decrease after short increase in the moment of energy release,which corresponded to the borehole blowout events.The acoustic emission events distributed more densely around the borehole,and each specimen had the region with the stripped distribution.The number of acoustic emission events,the number of ringing and the energy would increase with the increase of loading time,especially in the blowout stage.The experimental results reveal the borehole blowout process effectively.%为了研究深部条件下的煤岩体动力显现特征规律,运用钻孔喷孔试验系统进行了不同载荷作用下的钻孔喷孔试验,测试并分析比较煤试样在试验过程中的应力、应变、钻屑量、声发射等参数.结果表明:只有当煤样加载压力超过某一临界值后,才会发生钻孔喷孔现象;加载压力越大,煤试件的钻屑量越多,钻孔喷孔次数越多;同时,喷孔时伴随较大煤岩颗粒喷出,钻孔喷孔是一个能量瞬间释放的过程,侧向应力和应变在能量释放瞬间会经历突然减小或经过短暂的增加后骤然减小的过程,与钻孔喷孔事件相对应;声发射事件除在钻孔周围分布比较密集外,每个试件也有呈条带状分布的区域.声发射事件数、振铃数、能量等都随着加载时间的增加而增加,在喷孔阶段更加明显.试验结果有效揭示了钻孔喷孔过程.