Effective evaluation of pressure relief drilling for reducing rock bursts and its application in underground coal mines
Effective evaluation of pressure relief drilling for reducing rock bursts and its application in underground coal mines
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煤矿井下泄压钻孔减爆效果评价及应用
DOI：
10.1016/j.ijrmms.2018.12.010
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发表时间：
2019-02-01
影响因子：
7.2
通讯作者：
Gao, Liqun
中科院分区：
文献类型：
--
作者：
Zhang, Shichuan;Li, Yangyang;Gao, Liqun
冲击地压是煤矿地层中的一种极端行为，可造成人员伤亡和严重的经济损失。卸压钻孔是煤矿中广泛使用的一种释放高应力集中，有效降低岩体体积弹性势能的方法，可以有效地减少煤矿井下冲击地压的发生。根据阳城煤矿冲击地压发生区的实际地质条件，采用不同卸压孔数和钻孔结构的石膏型煤质材料，进行了一系列力学性能试验研究。研究了钻孔煤质材料在单轴压缩下的强度、耗能指数等参数的变化，并分析了实验中钻孔围岩中的裂纹扩展特征。利用断裂力学原理预测岩石中的显式破裂过程的数值程序FRACOD被用来模拟实验室试验，并将数值结果与试验结果进行了比较。并利用该程序研究了三个不同几何构型的钻孔的起裂效果，从而研究了局部裂缝在钻孔周围的萌生和扩展。结合钻孔围岩应力变化特点，确定了阳城煤矿卸压钻孔的最佳布置形式。结果表明，钻井密度越大，钻孔周围岩石裂隙发育程度越高，释放的能量越大，卸压效果越好。最后，本研究为卸压钻井最佳布置参数的选择提供了一种新的方法，可为今后相关领域的研究提供参考。
Rock bursts are an extreme behaviour in coal mine strata that can cause fatalities and severe economic losses. Pressure relief drilling is a widely used method in coal mines to release high stress concentrations and effectively reduce the rock mass volumetric elastic potential energy; thus, this method can effectively reduce the occurrence of rock bursts in underground coal mines. Based on actual geologic conditions in the area of a rock burst that occurred in the Yangcheng Mine, a series of experimental studies on mechanical properties are conducted using gypsum-type coal-like materials with different numbers and configurations of pressure relief boreholes. The change in parameters, such as the strength and energy dissipation index of bored coal-like materials under a uniaxial compression, is studied, and the fracture propagation characteristics in the rock surrounding the boreholes in the experiments are analysed. FRACOD, which is a numerical code that predicts the explicit fracturing process in rocks using fracture mechanical principles, is then used to simulate the laboratory tests, and the numerical results are compared with the experimental results. The code is also used to study the relief effect of three boreholes with different geometrical configurations; thus, local fracture initiation and propagation around the boreholes are investigated. Combined with the characteristics of the stress change in the rock surrounding the boreholes, the optimal configurations of the pressure relief boreholes for the Yangcheng coal mine are determined. The results have shown that the larger the drilling density is, the more the rock fracture development around the boreholes, the greater the energy release and, hence, the more effective the relief effect. Finally, this study presents a new methodology for choosing the optimal layout parameters for pressure relief drilling, which could aid future research in related fields.