深部采动巷道顶板稳定性分析与控制

深部采动巷道冒顶事故是当前煤炭资源开采中面临的重大难题。基于深部采动巷道围岩应力环境,分析了双向非等压条件下巷道围岩塑性区形成的力学机制及其形态特征,并对顶板稳定性影响因素进行了探讨。结果表明:1深部采动巷道围岩双向压力比值λ(0λ1)较小时,围岩塑性区形态不再是圆形和类椭圆形,而呈现出蝶形分布的特征,当碟叶位于巷道顶板上方时,容易发生冒顶;2采动应力方向决定围岩最大破坏深度的位置,并控制潜在冒落区的范围,当围岩最大破坏深度与潜在冒落高度相同时,顶板稳定性最差。要保持顶板围岩稳定,支护体必须要有足够的长度和延伸性能,据此,提出了可接长锚杆支护技术,现场试验结果表明,可接长锚杆较好地适应了顶板围岩的剧烈下沉,取得了良好的支护效果。

Stability analysis and control technology of mine roadway roof in deep mining

Roof caving accidents of mine roadway in deep mining is a major problem faced with the exploitation of coal resources.Based on the stress environment of the mine roadway surrounding rock in deepmining,the formative mechanics and morphological characteristics of the plastic zone of surrounding rock on bidirectional non-constant pressure were analyzed,and the factors affecting the stability of the mine roadway roof in deep mining were discussed.The results indicate that: ① When the two-way pressure ratio λ(0<λ<1) of the surrounding rock of mine roadway is less,the morphology of the plastic zone of roadway surrounding rock is no longer circular or ovaland shows the characteristics of butterfly distribution;when the butterfly leaf is above the roadway roof,the roof caving is easy to occur;② The location of the maximum damage depth is determined by the direction of mining-induced stress,which also determines the height and the range of potential caving zone;when the maximum damage depth of the surrounding rock is equal to the potential caving height,the roof is most unstable.To ensure the roof stability,the support must have enough length and extension performance,accordingly,the long-extension bolt support technology is put forward;the field tests indicate that: the long-extension bolt adapts to the intense subsidence of roof surrounding rock,and better supporting results are obtained.