深井岩巷空顶区失稳及安全空顶距研究

Study on instability and safe empty roof distance of deep rock roadway empty roof area

为解决深井岩巷掘进过程中空顶区冒顶、片帮的安全问题,以吕家坨矿-950四采区回风道为工程背景,综合采用理论分析与数值模拟相结合的方法开展研究。运用卡斯特纳公式计算了巷道开挖之后塑性区半径为3.19 m,以此为基础建立了一端简支一端固支的空顶区岩梁力学模型,推导出了最大空顶距表达式。研究结果表明,-950四采区回风道的安全空顶距为2.6 m;运用GDEM模拟分析了不同工况下围岩的应力和损伤情况,模拟结果表明前方岩壁的支撑作用要明显高于后路锚杆对顶板的支撑作用,Ⅲ型工况下围岩的应力和损伤情况与Ⅱ型工况相差不大,考虑炮孔深度受限,空顶距为2.4 m时较为合适。

In order to solve the safety problems of roof fall and rib spalling in the hollow roof area during the excavation of deep mine rock roadway,the return air duct of-950 fourth mining area in Lvjiatuo Mine was taken as the engineering background,and the research was carried out by combining theoretical analysis with numerical simulation.The radius of the plastic zone after the excavation of the roadway is calculated to be 3.19 m by using the Castner formula.Based on this,a mechanical model of the rock beam in the empty roof area with one end simply supported and one end fixed is established,and the expression of the maximum empty roof distance is derived.The research results show that the safe empty top distance of the return air duct in the-950 fourth mining area is 2.6 m;gDEM was used to simulate and analyze the stress and damage of surrounding rock under different working conditions.The simulation results show that the supporting effect of the front rock wall is significantly higher than that of the rear anchor rod on the roof.The stress and damage of the surrounding rock under the type III working condition are not much different from those under the type II working condition.Considering the limited depth of the blast hole,it is more appropriate when the empty top distance is 2.4 m.