综采工作面覆岩压实区演化采高效应分析及应用

Analysis and application on the mining height effect of evolving law of compaction area at fully mechanized face

采用相似材料物理模拟试验及理论分析,研究在不同采高条件下覆岩压实区的动态演化规律及形态特征。研究结果表明:在煤层开采之后,采动覆岩离层量分布呈"马鞍"状,采空区底板在一定区域内存在应力集中,结合两者可作为压实区底部边界判定依据;采空区覆岩压实区的形态及时空演化规律受采高与工作面推进距离的共同影响,得到了压实区宽度、高度及垮落角度的演化规律与采高的关系;同时,结合冒落带岩体的碎胀特征与底板应力集中的特点,分析了压实区压实程度的采高效应,即在一定范围内,采高越高,压实程度越大。基于采动裂隙椭抛带理论,在试验结果分析的基础上,建立了采动裂隙椭抛带压实区的数学表达方程,为卸压瓦斯抽采系统的布置及参数优化提供借鉴。

Dynamic evolution law and fissure forms of overlying strata compaction area were studied by using similar materials physical similarity simulation and theory analysis.The research results show that the separation values are distributed with the shape of ＂saddle＂and there is a stress concentration in a certain area in gob floor and the bottom boundary of compaction area can be determined by combining both theories. Fissure forms and the dynamic evolution law of goaf overburden rock compaction area are affected by both mining height and advanced distance,which provides the relationship between the evolution law of the width,high of compaction area,caving angel and mining height.Meanwhile,the mining height effect of the compaction degree in compaction area has been analyzed by combining the bulking factor characteristic of caved rock area and the feature of stress concen-tration in bottom. In a certain range,the higher of the mining height is,the larger compaction degree will be.Based on the theory of elliptic paraboloid zone and the analysis of experiment results,the mathematical expression equation of mining fracture compaction area is established which provides a theoretical basis for the distribution and parameter optimization of pressure relief gas extraction system.