综放工作面充填过空巷顶板失稳机理及控顶研究

Study on instability mechanism and top control of overfilled roof in fully mechanized caving face

为了解决综放工作面过空巷时易造成压架、大面积冒顶等技术难题,以山西某矿4318综放工作面过空巷为背景,建立空巷基本顶力学模型,揭示空巷顶板稳定机理,确定顶板破断产生滑落失稳是造成压架的主要原因,进而确定维持空巷顶板稳定的最小支护阻力;采用FLAC3D软件对不同充填体强度下空巷围岩应力、塑性区宽度和巷道变形进行分析,确定了过空巷时的最佳充填体强度。研究结果表明:工作面空巷顶板所需支护阻力应大于4.5 MPa,合理的充填体强度为7.1 MPa。工业试验对比分析了木垛支护、锚杆(索)支护和高水材料充填3种方式,证明高水速凝材料充填支护效果最好,顶板未曾出现冒落现象,帮部也保持了稳定,能够保证综放工作面正常推进。

In order to solve such technical problems as support break-off, large area roof falling when the fully mechanized caving face crosses gobs, the basic top mechanical model of the empty alley is established with the background of the fully mechanized caving face 4318 in a mine in Shanxi, which reveals the stability mechanism of the roof of the empty roadway, identifies the major cause of crushing to be the sliding instability of roof fracture, and further determines the minimum value of supporting resistance to maintain roof stability in the abandoned roadway. Besides, the FLAC^3D numerical simulation software is adopted in this paper to analyze the stress of surrounding rock, the width of plastic zone and the deformation of roadway under different backfill strength, and to determine the optimum backfill strength. The theoretical analysis has shown that the roof support resistance of the abandoned roadway should be greater than 4.5 MPa, and the optimum strength of the filling body is 7.1 MPa. Furthermore, three types of pigsty timbering, bolting (cable) support and filling with high-water quick-setting material are compared and analyzed in industrial trials. The results have shown that the high-water quick-setting material has the best filling and support effect, and the roof does not appear to fall, and the gang also maintains stability, which can ensure the normal advancement of the fully mechanized caving face.