沟谷地形浅埋煤层开采覆岩形态演化规律研究

    Study on evolution law of overburden morphology in shallow coal seam mining of gully terrain

    • 摘要: 以转龙湾煤矿231采区公涅尔盖沟区域Ⅱ-3煤层开采为研究背景,基于岩层控制的关键层理论,运用相似物理模拟实验研究浅埋煤层开采覆岩破坏场、位移场及采动裂缝演化规律。研究结果表明:受沟谷地形载荷分布影响,主关键层周期破断距随着载荷层厚度的增大而减小,模型1、模型2、模型3中主关键层周期破断距分别为7~17、12~24、11~23 cm;模型1、模型2、模型3中主关键层垂直位移最大值分别为22.77、24.42、20.98 mm,结构缺失的关键层破断后不易形成稳定的“砌体梁”承载结构,是导致模型2主关键层垂直位移最大值大于模型1和模型3的主要原因;随着工作面的推进,覆岩运移影响范围在竖直和水平方向逐渐增大;主关键层处于周期破断阶段,采动裂缝形成和发育进入活跃期,其数量和间距与主关键层破断规律有关;采动裂缝具有动态变化特征,沟谷底部及两侧坡脚裂缝容易受挤压影响,裂缝宽度较小甚至闭合,地表平坦区域裂缝形态相对稳定。

       

      Abstract: Taking the mining of II-3 coal seam in Gongniergaigou area of 231 mining area of Zhuanlongwan Coal Mine as the research background, based on the key strata theory of strata control, the similar physical simulation experiment is used to study the failure field, displacement field and mining-induced fissures evolution law of overburden strata in shallow coal seam mining. The results show that the periodic breaking distance of the main key strata decreases with the increase of the thickness of the load layer due to the influence of the valley terrain load distribution. The periodic breaking distance of the main key strata in model 1, model 2 and model 3 is 7-17 cm, 12-20 cm and 11-23 cm, respectively. The maximum vertical displacement of the main key strata in model 1, model 2 and model 3 is 22.77 mm, 24.42 mm and 20.98 mm, respectively. It is not easy to form a stable “masonry beam” bearing structure after the key strata of the missing structure is broken, which is the main reason why the maximum vertical displacement of the main key stratum of model 2 is greater than that of model 1 and model 3. With the advancement of the working face, the influence range of overburden migration gradually increases in the vertical and horizontal directions. The main key stratum is in the stage of periodic breaking, and the development and formation of mining-induced fissures enter the active period. The number and spacing of mining-induced fissures are related to the breaking law of the main key stratum. The mining-induced fissures have dynamic change characteristics. The mining-induced fissures at the bottom of the valley and the slope foot on both sides are easily affected by extrusion. The fissures width is small or even closed, and the fissure morphology in the flat surface area is relatively stable.

       

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