高强度开采邻空工作面覆岩裂隙及能量演化规律研究

    Study on overlying rock fissure and energy evolution law of high intensity mining working face adjacent to gob

    • 摘要: 西部矿区高强度开采导致工作面上覆岩层结构及地表严重破坏,进而导致地表生态环境恶化。以大柳塔矿为工程背景,通过现场监测和理论分析研究了高强度开采邻空工作面覆岩裂隙及能量演化规律;采用FLAC3D数值模拟分析得出邻空12203工作面垂直应力、覆岩破坏范围和能量积聚特征及不同回采阶段关键层能量演化规律。研究结果表明:初次来压后地表开裂并产生塌陷,裂缝可见深度为0.1~0.7 m,周期来压步距为7~17 m,平均步距12 m;12203工作面上覆岩层破坏范围随回采速度增大,覆岩裂隙发育范围、地表破坏范围均与工作面推进速度呈正相关关系,回采速度对邻空工作面覆岩破坏范围影响较大;区段煤柱应力随回采速度增大而增大,工作面前方50 m仍受较高静载应力作用,巷道易冲击失稳;12203工作面邻空端头处能量密度值及能量积聚区域,采场围岩扰动强烈,覆岩能量积聚来不及释放,易造成顶板围岩冲击失稳。

       

      Abstract: The high-intensity mining in the western mining area has led to severe damage to the overlying rock structure and surface of the working face, resulting in the deterioration of the surface ecological environment. Taking Daliuta Mine as the engineering background, the study investigated the overlying rock fractures and energy evolution laws of high-intensity mining adjacent to the working face through on-site monitoring and theoretical analysis; using FLAC3D numerical simulation analysis, the vertical stress, range of overlying rock failure, and energy accumulation characteristics of the 12203 working face and the evolution law of key layer energy in different mining stages were obtained. The results showed that after the initial compaction, the surface cracked and collapsed, with visible depths ranging from 0.1 m to 0.7 m. The periodic compaction step distance was 7-17 m, with an average step distance of 12 m; the range of overlying rock damage on the 12203 working faces increases with the increase of mining speed. The development range of overlying rock fractures and the range of surface damage are positively correlated with the advancing speed of the working face. The mining speed has a significant impact on the range of overlying rock damage on adjacent working faces; the stress of the coal pillar in the section increases with the increase of the mining speed, and 50 m in front of the working face is still subjected to high static stress, and the roadway is prone to impact instability; the energy density value and energy accumulation area at the adjacent goaf end of the 12 lower 201 working face are strongly disturbed by the surrounding rock of the mining area, and the energy accumulation of the overlying rock cannot be released in time, which can easily cause instability of the roof surrounding rock due to impact.

       

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