Study on instability and safe empty roof distance of deep rock roadway empty roof area
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.
empty roof areaempty top distanceplastic zoneroof instabilityrock beam modelGDEM simulation
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