陕西煤炭

陕西瑞能煤矿采用免爆破的密集钻孔切顶卸压沿空留巷工艺，以瑞能煤矿203工作面为研究背景，对密集钻孔切顶高度、定向切缝钻孔角度、钻孔孔径以及钻孔间距等密集钻孔切顶卸压沿空留巷工艺的关键参数开展数值模拟研究并进行现场监测。研究结果表明，孔径增加对于密集钻孔之间塑性区贯通影响较小；切顶角度的增加可以在一定程度上减弱采空区顶板的水平约束，确保采空区顶板的顺利垮落；适当增加切顶高度可在确保切顶成功的同时减小巷旁支护阻力；较小的孔间距有利于钻孔间塑性区贯通。综上确定密集钻孔切顶关键参数为切孔倾斜角度15°、切顶高度8 m、孔径48 mm、孔间距200 mm。工作面回采过后，后巷顶底板中部最大移进量为250 mm,切顶侧顶底板最大移进量为170 mm,留巷段矿压显现缓和。切顶卸压以及成巷效果满足矿井使用需求。从而验证了密集钻孔切顶卸压沿空留巷关键参数的确定方法，为该工艺在同类型矿井进行使用提供了工程参考经验。

Blasting-free dense borehole roof cutting technology is increasingly used in gob-side roof cutting self-forming roadway.Taking the 203 working face of Ruineng Coal Mine as the research background, the key parameters of the dense borehole roof cutting and pressure relief gob-side entry retaining process, such as the height of the dense borehole roof cutting, the angle of the directional slit drilling, the borehole aperture and the borehole spacing, were studied.The results show that the increase of the aperture has a larger effect on the plastic zone connecting between dense boreholes; the increase of top-cutting angle can in a certain extent weaken the horizontal restriction of goaf roof, ensuring the timely collapse of goaf roof; the reasonable increase of top cutting height can reduce support resistance of roadway side while ensuring the success of top cutting; and the smaller spacing of borehole is conducive to the connecting of plastic zones.The roof cutting parameters with a roof cutting height of 8 m, a hole inclination angle of 15°,a hole diameter of 48 mm, and a hole spacing of 200 mm were determined.The roof of the goaf can fall in time and form the roadway side with stable bearing capacity.After mining of the working face, the maximum displacement of the roof and floor in the middle of the roadway is 250 mm, and the maximum displacement of the roof and floor on the roof cutting side is 170 mm.The pressure behavior of the retention section is stable.The effect of roof cutting and pressure relief and roadway formation meets the needs of mine.The method of determining the key parameters of gob-side entry retaining with dense borehole roof cutting and pressure relief is verified, which provides engineering reference for the same type of mines.