长城六矿中硬顶板倾斜工作面切顶留巷关键参数研究

Study on key parameters of roof cutting and retaining roadway in medium-hard roof of the inclined working face in Changcheng No.6 Mine

针对长城六矿1301S工作面沿空巷道围岩破坏失稳控制难题,首先,采用UDEC数值模拟方法揭示了1301S工作面侧向覆岩破断运动规律,发现侧向覆岩破断位置均位于巷道上方,且直接顶悬臂结构长度约为1.8m;其次,通过构建侧向覆岩结构力学模型,获得了切顶前后实体煤和矸石支撑体支承应力解析表达式,根据表达式进行算例分析得到切顶前后实体煤支承应力保持不变,均为1.27MPa,靠近巷道左侧矸石支撑体支承应力降低了56.89%;再次,通过理论计算确定了巷旁切顶参数,即切顶高度11m、切顶角度20°、切缝孔间距500mm;最后,设计了1301S工作面运输顺槽切顶留巷技术方案并开展了工业性试验。研究结果表明:切顶后巷道顶底板移近量和两帮移近量分别为1240mm和265mm,与未切顶相比分别降低了12.68%和70.22%,围岩整体稳定性较好。该研究可为相同或相似条件下切顶留巷技术应用及关键参数设计提供参考和借鉴。

In order to control the destabilization of surrounding rock along the roadway of 1301S working face of Changcheng No.6 Mine,firstly,the numerical simulation method of UDEC is adopted to reveal the movement law of lateral overburden breakage of 1301S working face,and finds that the locations of lateral overburden breakage are located in the upper part of the roadway,and the length of cantilever structure of immediate roof is about 1.8 m;secondly,through the construction of the lateral overburden structural mechanics model,the analytical expressions of supporting stresses in the solid coal and gangue support before and after roof cutting have been obtained,and according to the expression of the case analysis,the solid coal supporting stress before and after the roof cutting is kept unchanged,both of which are 1.27 MPa,and the supporting stress in the gangue support body near the left side of the roadway is reduced by 56.89%;thirdly,the parameters of the roadway side roof cutting are determined by theoretical calculations,the height of the roof cutting is 11 m,the angle of the roof cutting is 20°,and the spacing of the cut-off holes is 500 mm;finally,roof cutting and retaining roadway technical program of 1301S working face transporting roadway is planned and carried out in industrial test.The research results show that after roof cutting,the displacement of roof and floor two sides of the roadway is 1240 mm and 265 mm,respectively,compared with the non-roof cutting are reduced by 12.68%and 70.22%,and the overall stability of the surrounding rock is good.This study can provide reference for the application of the technology and design of key parameters of roof cutting and retaining roadway under the same or similar conditions.