特厚煤层开采主亚关键层活动特征及其对覆岩移动的控制规律研究

主亚关键层的活动特征及其对覆岩移动的控制规律是研究特厚煤层开采顶板控制的主要依据。本文依据老三沟井田地质条件和赋存状况,通过物理相似模拟试验的方法,分析研究准格尔中部矿区老三沟井田煤层开采中主亚关键层活动特征及其对覆岩移动的控制作用。研究表明,基本顶(亚关键层)初次来压步距在45m左右,周期来压步距在15～20m之间;当工作面向前推进约130m,主关键层弯曲下沉量增大,且在两端发育纵向裂纹,而采空区中部覆岩压实,裂隙逐步闭合;由于关键层位结构的存在,使得开采过程中覆岩的大范围剧烈活动降低了对工作面的影响。

Main and sub-key strata activities characteristics and their control laws on movements of overburden stratum in mining of especially-thick coal seam

Main and sub-key strata activities characteristics and their control laws on movements of overburden stratum are the main basis of studying the roof control in mining of especially-thick coal seam.According to the geological and the occurrence conditions of Laosangou mine field,with method of physical simulation experiment,the paper analyzes the main and sub-key strata activities characteristics and their control laws on movements of overburden stratum in coal mining of Laosangou mine field in central part of Zhungeer.The result shows that the first weighting interval of basic roof(sub-key stratum) is 45m or so,and the periodic weighting interval is between 15~20m;when the working face advances about 130m,the bending subsidence of the main key stratum will increase,and the longitudinal cracks will happen at its two ends,while the overburden stratum in the central part of the gob is compact,and cracks are gradually closed;the existence of the key strata structure decreases the impact of wide ranging severe activities of overburden stratum in the mining process on the working face.