复合顶板高瓦斯厚煤层综放工作面覆岩“两带”动态发育特征

以余吾煤业为试验矿井,采用钻孔两端封堵分段注水装置和钻孔电视系统,探测综放开采上覆岩层"两带"高度,对采动前后裂隙倾角、数量与深度关系、数量与宽度关系进行数字化分析,并就采动过程裂隙演变情况进行相似模型与数值模拟试验。结果表明:余吾煤业综放开采冒落带高度为27～32 m,裂隙带高度为58～61 m,采动前裂隙以高角度、低宽度为主;随着采煤工作面的逐步推进裂隙数量呈直线上升,且增加的裂隙以小角度、中宽度为主;采动过程中裂隙的主要聚集区在煤壁前后,覆岩裂隙密度分布曲线呈两端和中间高,如"波浪"型。

DYNAMIC DEVELOPMENT CHARACTERISTICS OF TWO ZONES OF OVERBURDEN STRATA UNDER CONDITIONS OF COMPOUND ROOF, HIGHLY GASSY AND THICK COAL SEAM IN FULL-MECHANIZED TOP COAL CAVING FACES

Taking Yuwu coal company as the experimental mine,by using the equipment which is sealed two ends by capsules in borehole,affused measurable water between the two capsules and borehole televiewer system,overburden two zones height of fully-mechanized top caving are monitored and analyzed through the digital relationship of fractures around mining such as change of dip angle,numbers and depth,numbers and width.At the same time,similarity model and numerical model experiment of fissure development evolution are carried out.The results show that:(1) Caving zone height changes from 27 m to 32 m and fractured zone height changes from 58 m to 61 m;(2) The fracture characteristics are mainly with high angle and low width before mining,with small angle and middle width after mining;with the mining of working face,the numbers of fractures increase with straight line;(3) The fractures cluster region mainly focuses near the coal wall,and the fractures density distribution curves of overlying strata are high at two ends and middle of working face,just like wave-shapes.