密集钻孔切顶技术主要通过对采场侧向顶板围岩结构进行改造，利用覆岩载荷和顶板自重切落基本顶，能够有效降低巷道顶板压力。通过统计国内部分矿井密集钻孔切顶卸压沿空留巷技术的应用案例，对钻孔关键参数及留巷效果进行了分析，并对密集钻孔切顶关键参数主要影响因素进行研究。研究结果表明：密集钻孔切顶适用于不同厚度的煤层，切顶效果取决于切顶高度、切顶角度、钻孔直径与间距是否合理。由于密集钻孔切顶时顶板在回采前未完全破断，在回采后，煤层厚度越大，顶板下沉回转在钻孔周围产生的拉伸应力就越大，密集钻孔顶板就越容易发生破断，煤厚的增加有利于顶板的自主破断。密集钻孔切顶高度随煤厚及基本顶厚度增加而增加；随煤厚增加切顶钻孔角度对切顶的影响逐渐减小，切顶角度呈现降低的趋势；密集钻孔孔径与孔间距二者共同作用影响密集钻孔顶板破断效果，D/B值(孔间距与孔径之比)在一定范围内随煤厚而增加，随基本顶强度增加而减小。根据统计结果采用工程类比法，并结合切顶钻孔主要影响因素研究结果，提出了密集钻孔切顶关键参数确定方法，并在赵家寨矿11210工作面回风巷进行了密集钻孔切顶留巷试验，现场留巷效果较好，证明该方法实用有效，具有一定的工程参考价值。

The technology of roof cutting by dense drilling is mainly through the transformation of the surrounding rock structure of the lateral roof of the stope, and the use of overburden load and roof weight to cut off the basic roof can effectively reduce the roof pressure of the roadway. This paper analyzes the key parameters of drilling and the effect of retaining roadway by analyzing the roof cutting and pressure relief by dense drilling technology along the empty roadway in some mines in China, and studies the main influencing factors of the key parameters of roof cutting by dense drilling. The results show that the technology of roof cutting by dense drilling is suitable for coal seams with different thicknesses, and the effect of roof cutting depends on whether the cutting height, cutting angle, drilling diameter and spacing are reasonable. Because the roof is not completely broken before recovery when the roof is cut by dense drilling, after recovery, the greater the thickness of the coal seam, the greater the tensile stress generated by the roof subsidence and rotation around the drilling, the more easily the roof with the dense drilling is to break, and the increase of coal thickness is conducive to the independent breaking of the roof. The roof cutting height of dense drilling increases with the increase of coal thickness and main roof thickness. With the increase of coal thickness, the influence of drilling angle on roof cutting gradually decreases, and the drilling angle shows a decreasing trend. The combined effect of dense drilling aperture and spacing affects the fracture effect of roof with dense drilling. The D / B value ( the ratio of drilling spacing to drilling diameter ) increases with the increase of coal thickness within a certain range, and decreases with the increase of main roof strength. According to the statistical results, the engineering analogy method is adopted, and combined with the research results of the main influencing factors of roof cutting by dense drilling, the method for determining the key parameters of roof cutting by dense drilling is put forward. The test of roof cutting by dense drilling and retaining roadway is carried out in the return laneway of 11210 working face in Zhaojiazhai Mine. The effect of roadway retaining is good, which proves that the method is practical and effective, and has certain engineering reference value.