基于深孔预裂爆破的厚硬顶板控制实践

Control practice of thick and hard roof based on deep-hole pre-splitting blasting

针对厚硬顶板工作面开采强矿压问题,以潘北矿11313工作面为工程背景,通过理论分析基本顶破断特性,制定了厚硬基本顶深孔预裂爆破方案,利用数值模拟研究了厚硬基本顶在不同深孔预裂爆破厚度下围岩应力演化规律及有效深孔预裂爆破厚度下超前支承压力分布。模拟结果表明;应力拱向运输巷侧旋移且应力拱拱高随爆破厚度的增大而增大,应力拱形态由勺状转变为椭圆状;当基本顶预裂爆破厚度为12 m时,工作面超前支承压力影响范围和超前支承压力峰值距工作面煤壁的距离与爆破前相比分别增大了8.5,18.8 m,超前支承压力集中系数由爆破前的1.67减小为爆破后的1.3。现场监测结果表明:厚硬基本顶预裂爆破后,工作面下部支架最大载荷和平均载荷降低,支架动载系数发生明显波动,煤壁片帮得到有效控制。

In view of problem of strong mine pressure on working face with thick and hard roof,taking 11313 working face of Panbei Mine as engineering background,based on theoretical analysis of breakage characteristics of main roof,deep-hole pre-splitting blasting scheme of thick and hard main roof was formulated,and stress evolution law of surrounding rock under different thickness of deep-hole pre-splitting blasting and distribution of advancing abutment pressure under effective thickness of deep-hole pre-splitting blasting were studied by numerical simulation.The simulation results show that stress arch rotates to the side of transport roadway,stress arch height increases with the increase of blasting thickness and stress arch shape changed from spoon to ellipse.When thickness of main roof pre-splitting blasting is 12 m,influence range of advancing abutment pressure and distance between peak abutment pressure and coal wall of the working face increase by 8.5 m and 18.8 m respectively compared with that before the blasting,and advancing abutment pressure concentration coefficient decrease from 1.67 before blasting to 1.3 after blasting.The field monitoring results show that after the pre-splitting blasting of thick and hard main roof,the maximum load and average load of support in lower of working face decrease,dynamic load coefficient of support fluctuates significantly,and rib spalling of coal wall is effectively controlled.