厚硬顶板切顶留巷最优参数及围岩稳定性分析

Optimal Parameters and Surrounding Rock Stability Analysis for Roof Cutting and Entry Retaining with Thick Hard Roof

为确定厚硬顶板切顶留巷最优技术参数,选取5 m、10 m、15 m切顶高度和0°、10°、15°、20°切顶角度,通过理论分析和3DEC数值模拟,对厚硬顶板切顶成巷形态和围岩稳定性进行研究。研究结果表明:切顶后巷道顶板形成“短臂梁”结构,当切顶高度和切顶角度一定时,切落顶板对巷道顶板“短臂梁”支撑力越大,其顶板所需的支护力F则越小,因此在切顶成巷时,需尽量使切落顶板充分接顶;随切顶高度增大,巷道实煤体一侧水平位移值随之增大、垂直位移随之减小,而巷道低位顶板水平位移几乎均为0;对厚硬顶板切顶成巷时需保持倾斜切缝,而随着切顶角度增大,巷道顶板垂直位移和实煤体一侧水平位移随之增大。基于此,综合确定10 m切顶高度、10°~15°切顶角度的最优切顶参数。

In order to determine the optimal technical parameters of roof cutting and entry retaining with thick hard roof, the cutting heights of 5 m, 10 m and 15 m and the cutting angles of 0°, 10°, 15° and 20° were selected. Through theoretical analysis and 3DEC numerical simulation, the shape of the roadway formed by the thick hard roof and the stability of the surrounding rock are studied. The results show that the roadway roof forms a “short arm beam” structure after roof cutting. When the roof cutting height and the roof cutting angle are constant, the greater the supporting force of the cut roof on the “short arm beam” of the roadway roof, the smaller the supporting force F required by the roof. Therefore, when cutting the roof into the roadway, try to make the cut roof fully connect to the roof;With the increase of the roof cutting height, the horizontal displacement value of the solid coal body side of the roadway increases and the vertical displacement decreases, while the horizontal displacement of the low roof of the roadway is almost zero;When the thick hard roof is cut into the roadway, it is necessary to maintain the inclined cutting seam. With the increase of the roof cutting angle, the vertical displacement of the roadway roof and the horizontal displacement of the solid coal body side increase. Based on this, the optimal roof cutting parameters with a roof cutting height of 10 m and a roof cutting angle of 10° to 15° were comprehensively determined.