深井不同层位底板岩巷与煤巷相互影响研究

Mutual influence between floor rock roadway and coal roadway in different strata for deep mining

深井煤巷掘进突出危险性高,布置底板岩巷条带预抽煤层瓦斯是降低煤层瓦斯压力、掩护煤巷安全掘进的有效方法。底板岩巷的层位布置及其与上部煤巷之间的相互影响是值得研究的问题。本研究通过数值分析方法,以首山一矿为工程背景,基于采面地质条件建立了离散元数值模型;根据巷道掘进先后关系,从岩层应力变化、围岩变形、损伤分布分析了不同垂距下底板岩巷与上部煤巷之间的相互影响。研究结果表明:底板岩巷对上部煤层有一定的卸压作用,随着两巷垂距的增加,煤体应力降低幅度减小;煤巷掘进对底板岩巷围岩变形有较大影响,增加垂距会降低影响程度;底板岩巷的围岩损伤受底板岩巷层位选择的影响较大,损伤区域主要发生在软岩层、薄岩层附近。首山一矿工作面最终确定底板岩巷与煤巷的垂距为12 m,现场考察结果表明此垂距下底板岩巷和煤巷稳定性良好。

Due to the high risk of coal and gas outburst in deep roadway tunneling,gas pre-extraction from the floor rock roadway strip is an effective way to reduce coal seam gas pressure and protect the safety of coal roadway tunneling.It is worthy to study floor rock roadway horizon location and effects with upper coal roadway.Taking the Shoushan No.1 mine as an engineering example,a corresponding discrete element model was established based on the rock strata in numerical analysis.According to the sequence of roadway excavation,the effects between floor rock roadway and upper coal roadways in difference vertical distance were analyzed in rock stress,rock deformation and the damage distribution aspects.Results show the floor rock roadway has a certain unloading effect on the upper coal seam.With the increase of the vertical distance between floor and upper roadways,the reduction of coal body stress is getting small.The floor rock roadway wall rocks will get deformation as tunneling.The increase of vertical distance results in less effect.The damage of the floor rock roadway is mainly affected by the roadway position,and the soft or thin rock layers are not conducive to roadway stability.The vertical distance between the coal roadway and the floor rock roadway at Shoushan No.1 mine is finally determined as 12 m and the field investigation results show the floor rock roadway and coal roadway have good stability.