上覆局部采空下冲击危险工作面煤柱留设宽度研究

Research on the width of coal pillar in the face of impact danger under the overlying partial goaf

为研究上覆局部采空下冲击危险工作面区段煤柱的布置问题,以某矿I010203工作面为工程背景,通过现场监测、数值模拟、理论分析等方法对工作面区段煤柱冲击危险和合理宽度进行研究。现场监测和数值模拟结果表明:I010203工作面回采过程中,15 m宽区段煤柱微震事件频繁,能量释放剧烈,增大了工作面冲击危险;15 m宽煤柱在工作面回采后不能完全破坏,仍可承受较高应力并向下部煤层传递,增大了下伏煤层回采工作面的冲击危险。理论分析结果表明:当宽度为0~6 m时,煤柱破碎程度较高,不利于隔绝采空区及巷道稳定;当宽度大于10 m时,煤柱内出现弹性核区,应力增加迅速,冲击危险性增高;8 m宽煤柱既能隔绝采空区预防瓦斯,又能使应力最低,降低冲击危险的临界煤柱宽度,因此更合理的区段煤柱宽度为8 m左右。研究结果可为该矿井接续工作面和相似条件工作面回采的煤柱宽度留设提供理论依据。

In order to study the layout of coal pillars in the working face with impact risk under the overlying partial goaf, the coal pillar impact risk and reasonable width in the working face are studied by field monitoring, numerical simulation and theoretical analysis with the I010203 working face as the engineering background.The numerical simulation and field monitoring results show that during the mining process of I010203 working face, the microseismic events in the 15 m wide section of coal pillar are frequent and the energy is released violently, which increases the impact risk of working face.Moreover, the 15 m wide coal pillar can not be completely destroyed after the mining face, but can still bear the higher stress and transfer to the lower coal seam, which increases the impact risk of the mining face of the underlying coal seam.The numerical study shows that when the width is 0-6 m, the coal pillar crushing degree is higher, which is not conducive to the isolation of goaf and the stability of roadway.When the width is greater than 10 m, the elastic core zone appears in the coal pillar, the stress increases rapidly and the impact risk increases.8 m wide coal pillar is the critical coal pillar width that can not only isolate goaf to prevent gas, but also minimize stress and reduce impact risk.A more reasonable coal pillar width is about 8 m.The research results can provide a theoretical basis for setting the width of coal pillar in the joint working face and similar working face.