厚煤层综放工作面覆岩运移规律研究

Overburden Movement Law of Fully Mechanized Top Coal Caving Face in Thick Coal Seam

针对厚煤层综放工作面覆岩突然性断裂垮落导致动力灾害的问题,根据煤岩层赋存条件和开采布局,考虑工作面顶板裂隙分布规律和开采扰动影响,采用现场勘察、岩石力学实验、数值计算等分析方法,综合分析厚煤层综放工作面覆岩运移活动规律。结果表明:受重力作用,覆岩垮落自采空区中心向四周均匀发展,岩层在拉伸应力作用下拉伸应力区呈U形破坏分布;随着掘进深度与层位的延伸,工作面顶板破坏区相互铰接形成稳定结构,阻碍了顶板运动;工作面来压步距较大,覆岩垮落冲击矿压载荷量级较大,工作面中上部区域覆岩运移量大于下部区域。

According to the occurrence condition and mining layout of coal seams, considering the distribution laws of roof cracks and the influence of mining disturbance, this paper comprehensively analyzes the movement laws of overlying strata in fully mechanized caving working face in thick coal seams by means of on-site investigation, rock mechanics experiment and numerical calculation. The results show that the overburden caving develops uniformly from the center of the goaf to all sides under the action of gravity, and the tensile stress zone of the rock stratum presents U-shaped failure distribution under the action of tensile stress. With the extension of tunneling depth and level, the roof failure zone of the working face is hinged with each other to form a stable structure, which hinders the roof movement. The pressure step distance of the working face is larger, the magnitude of overburden caving and rock burst load is larger, and the overburden movement in the middle and upper part of the working face is larger than that in the lower part.