巷道卸压法应力迁变规律及卸压参数的确定

Stress Migration and Destressing Parameters of Roadway

北洺河铁矿-95 m 水平4#采场进路联巷及回采进路在掘进过程中或成巷后不久就发生片帮冒顶,采用密集的 U 型可缩式金属拱架仍未能控制住巷道围岩的变形与破坏。利用 flac3d 数值模拟的方法研究了不同卸压高度和宽度下采场进路应力分布状态,模拟结果表明,卸压对巷道不同部位的不同应力具有不同程度的卸压效果,卸压可有效降低仰拱处剪应力及巷道仰拱、两帮和底角的最大主应力,巷道顶底板的最大主应力随卸压工程的开挖而增加,卸压宽度对卸压效果影响显著,在北洺河铁矿条件下卸压工程超出巷道边界1～2 m 为宜。根据数值模拟结果和-80 m 分段回采界线的位置,确定卸压工程范围,采用房柱法进行卸压后,采场的应力集中程度得到有效降低,安全回采矿石15万 t,并为高应力矿山开采提供了卸压开采的新思路。

The rib spalling and roof falling were encountered during tunneling process of the-95 m sublevel drifts in 4 # stope of Beiminghe iron mine.Although lots of plastic U-shaped arches was mounted,the large deformation and failure of the drift were not under control. Numerical simulation by flac3D was utilized to study the stress distribution in the stope route under different distressing parameters.Results showed that destressing is effective in different part of the drift.The shear stress in the invert and the maximum principal stress in invert,side walls and bottom angle in the drift are decreased by destressing.While the maximum principal stress in the roof is increased during destressing.Destressing width affect the distress result obviously.The destressing width should exceed the boundary of the drift by 1 ~2 m.The destressing method in this project reduced the stress concentration effectively and 150 000 tons of ores were mined safely,which contributed a new idea for mining in high stress rock mass.