含硬夹矸大采高仰采综放面煤壁稳定性机理研究

Coal Wall Stability Mechanism of Up-dip Mechanized Top-coal Caving Face Mining with Large Mining Height and Harden Dirt Band

为了分析含硬夹矸对大采高仰采综放面煤壁稳定性的影响,采用理论分析与现场监测相结合的方法,建立了煤壁片帮的力学模型。通过控制变量法,依次变化顶板压力、夹矸层赋存高度以及仰采角度,控制其余变量不变,依据煤壁破坏的安全余量判别准则,观察变量变化对煤壁破坏的影响。结果表明:硬夹矸给上部煤层提供了向上的支撑力以及横向的摩擦力,上部煤壁失稳时,煤层沿着硬夹矸层面产生滑移破坏;安全余量与顶板压力和夹矸层赋存高度呈负的线性变化,安全余量与仰采角度呈三角函数余弦曲线变化,仰采角度越大,煤壁安全余量越小。

In order to analysis coal wall stability of up-dip mechanized top coal caving face with large mining height and harden dirt band, theory analysis and field monitoring were used, then mechanical model of coal wall spalling was built. According to control vari- ate method, roof pressure, dirt band thickness and up-dip mining angle were changed successively, and other variables were con- stant, according to safety margin criterion of coal wall broken, then the influence that variables to coal wall broken. The results showed that upper supporting pressure and lateral friction were provided by harden dirt band, the upside coal wall instability, coal seam ap- peared sliding broken along harden dirt band, negative linear variation appeared between safety margin, roof pressure and dirt band thickness. The relation between safety margin and up-dip mining angle wascosine curve, safety margin became smaller with up-dip an- gle increase.