地面深孔水压爆破弱化厚硬顶板技术研究

Research on weakening thick and hard roof by ground deep hole hydraulic blasting technique

浅埋深、厚硬顶板、特厚煤层开采时,为避免初次来压时顶板大面积垮落在巨大体积采空区形成强冲击波事故,提出地面深孔水压预裂爆破弱化厚硬顶板技术。采用理论分析和数值模拟方法验证了水压爆破的可行性、确定了合理的炮孔间距,并在口前煤业4302综放工作面成功进行了工业性试验。数值模拟结果显示,相同装药情况下,水耦合装药爆破岩石孔壁最大等效应力是空气不耦合装药的1.45倍,且爆生裂隙区范围扩大了38%。在炮孔直径180 mm、装药直径120 mm情况下,水压爆破岩石裂隙区直径能够达到11.06 m;现场试验成功解决了装药及堵塞等技术难题,实现了工作面初次来压提前,工作面继续推进时上覆岩层实现了正常周期性破断,验证了地面深孔水压爆破的可行性。

To prevent accidents caused by the strong shock waves resulting from large-scale roof caving during the first pressure in conditions of shallow burial depth,thick and hard roof,and ultra-thick coal seam mining,this paper proposed a ground deep hole hydraulic pre-fracture blasting technique to weaken the thick and hard roof.By using theoretical analysis and numerical simulation methods,the feasibility of hydraulic blasting was verified and the reasonable interval of holes was determined.Industrial tests in the 4302 comprehensive workface of Kouqian Coal Industry were then successfully conducted.Numerical simulation results showed that for the same charge,the maximum equivalent force of the borehole wall was 1.45 times higher and the explosive fissure zone was expanded by 38%when water-coupled charge blasting was used in comparison with air-uncoupled charge blasting.In the case of a borehole diameter of 180 mm and a charge diameter of 120 mm,hydraulic blasting could create a rock fissure zone with a diameter reaching 11.06 m.The field experiment effectively resolved the technical challenges related to charging and stemming,achieved an earlier occurrence of first pressure on the working face,and realized the normal periodic fracturing of the overlying rock with the continuous advancing of the working face,which confirmed the viability of the ground deep hole hydraulic blasting.