基于高压水力顺层钻割技术的冲击地压防治实践

Practice of rock burst prevention and control based on high-pressure hydraulic drilling and cutting technology along bedding

为提高回采工作面高应力区防冲卸压效率和效果,针对煤层注水、煤体钻孔卸压、爆破卸压等传统卸压方法存在的应用缺陷,运用高压水力顺层钻割技术对综放工作面冲击地压显现危险区域进行提前卸压处理,从理论上分析了该技术的卸压原理和可行性,在现场进行了实践应用,并用数值模拟和电磁辐射方法对卸压效果进行验证。结果表明:①高压水力顺层钻割技术钻孔沿工作面倾向顺煤层层理布置,以压力高于30 MPa高度聚能的水射流束切割破碎煤体,形成卸压空间,同时浸润弱化煤体,钻孔由内而外形成破裂区、塑性区、弹性区,并随着塑性区及破裂区煤体变形量的不断增加,塑性区及破裂区煤体变形、垮落,积聚的弹性能得到释放,煤岩体中的静载荷降低,消除冲击地压发生条件,防止冲击地压发生;②高压水力顺层钻割技术钻割时采用定点与反复动态相结合钻割方式,钻杆轴向与径向运动相结合,既保证钻进稳定性,又可形成多段圆盘状卸压空间和连续卸压孔洞,在煤层内可形成半径为300~400 mm的卸压空间,出煤量可达2.0~3.5 t;③数值模拟结果显示,采用高压水力顺层钻割技术卸压后煤体内部应力平均降幅达68.6%,电磁辐射现场监测钻孔施工前、后平均幅达60.92%,实施后巷帮应力降低区明显扩大,煤体内部应力显著降低,卸压效果良好。

In ocler to improve the efficiency and effectiveness of pressure relief in prevention and control of rock burst in the working face’s high stress area,it has put forward the use of bedding drilling technology of high pressure water for unloading process in advance in rock burst danger area of fully-mechanized top-coal caving mining face.It has avoided defects of drill hole pressure relief and coal seam water injection and blasting pressure relief and so on and analyzed theoretically unloading principle and feasibility of the technology.This has also verified pressure relief effect of numerical simulation and electromagnetic radiation.Results show that:①the layout of drill of bedding drilling technology of high pressure water is along the tendency of mining face and the coal layers of bedding.It cuts and breaks the coal by highly shaped water jet which pressure is higher than 30 MPa,and forms pressure relief space.It also infiltrates and weakens the coal body.The drill has formed rupture zone,plastic zone and elastic zone by inside and outside,and as the amount of deformation and the plastic zone and ruptured zone continuously increased,the zone has deformed and caved leading to accumulated elastic energy releasing,and the static load of coal and rock has become lower.The condition of rock bursts has eliminated,and rock burst has be prevented.②The bedding drilling technology of high pressure water has adopted the combination of fixed point and repeated dynamic drilling and the combination of axial and radial movement of the drill pipe,which not only guarantees the stability of drilling,but also forms multi-segment and discshaped pressure relief space and continuous relief holes.In the coal seam,pressure relief space with radius of 300-400 mm can be formed,and the output of coal can reach 2.0-3.5 t.③The numerical simulation results show that the average decrease of the internal stress value of the coal body is 68.6% and the average decrease value of the electromagnetic radiation monitoring is 60.92% by using bedding drilling technology of high pressure water.After use,the stress reducing area of lane has dramatically expanded and the internal stress value of coal has significantly reduced.The unloading effect is good.