覆沙层下大采高工作面覆岩运移规律

大采高开采的方法是提高煤炭资源回收、实现矿井高产高效的重要发展方向,但也造成工作面覆岩破坏严重。为此,文中以宁东煤田赋存的覆沙层下特厚煤层为背景开展大采全高工作面覆岩运移研究,运用相似模拟的方法并综合多种监测仪器从模拟现象、力源两个角度对大采高工作面覆岩运移、下沉乃至垮落的特征进行了全程监测与分析。研究表明:大采高工作面覆岩垮落初次来压步距较大,支架带压移架后极易发生直接顶乃至老顶的突然垮落,工作面来压强烈、伴随有明显的支架动载现象;延伸至地表的裂隙有诱发地表覆沙层弯曲、有溃入工作面的可能;模型开采结束后形成了6条贯穿至地表且与工作面推进方向成60°的垮落裂缝;模型内部各岩层下沉范围随着工作面的推进而不断扩大,呈U字型下沉趋势。

Overlying strata movement regularity in large mining height working face under sand covering layer

Large mining height mining is an important development direction of increasing coal recovery and achieving high production and high efficiency mine, but the destruction in the overlying strata is se- rious. In this paper, the law of overlying strata movement is researched for the sand covering and ex- tremely thick coal seam in Ningdong coalfield. The simulation and a variety of monitoring instruments are used, the characteristics of overlying strata migration, subsidence and collapse are analysed at the whole process of mining from the simulated phenomenon and force resource on the working face with large min- ing height. Research shows that：the first weighting step distance is relatively big in large mining height working face, the suddenly collape of immediate roof and main roof can easily occur when the support moves with pressure ,frame shift after intense pressure, the behavior of working face is strong, accompa- nied by obvious support dynamic phenomenon; the cracks extending to the surface have an possibility of inducing sand bending and bursting into the working face mining; 6 crack of running through the surface and having a 60 degree angle with the mining direction of working face ; the range of each stratum subsidence expands within model along with the working face advancing and forms a downward trend of ＂U＂.