浅埋煤层开采覆岩破坏与导水裂隙带发育高度研究

Study on overburden failure and development height of water conducting fracture zone in shallow coal seam mining

浅埋煤层覆岩破坏规律及裂隙发育特征与煤矿安全开采密切相关。为了研究浅埋煤层开采上覆岩层的扰动破坏规律与导水裂隙带发育特征,以柠条塔井田南翼2;煤S1233工作面为研究对象,通过相似材料模拟与数值模拟方法,对覆岩破坏规律及裂隙发育特征进行了研究。相似模拟实验表明,S1233工作面的初次来压步距约为60m,周期来压步距约为16m,导水裂隙带高度发育至地表,达165m,裂采比为27.5。数值模拟实验表明,导水裂隙带发育过程分为孕育、发生与缓增、突增及稳定4个阶段,导水裂隙带最终发育至地表,达165m,裂采比为27.5。参考柠条塔煤矿北翼现场钻孔实测结果,综合确定南翼2;煤开采裂采比大于27.5。研究成果可为浅埋煤层开采矿井水害防治和水资源保护提供指导。

The failure law and fracture development characteristics of overlying strata in shallow coal seams are closely related to the safe mining of coal mines.In order to study the disturbance failure law of overlying strata and the development characteristics of water conducting fracture zone in shallow coal seam mining,taking 2-2 coal S1233 working face in the south of Ningtiaota mine field as the research object,through similar material simulation and numerical simulation,the failure law of overlying rock and the characteristics of fracture development are studied.Similar material simulation show that the initial weighting interval of S1233 face is about 60 m,the periodic pressure step distance is about 16 m,the height of water conducting fracture zone is 165 m,and the mining-fracturing ratio is 27.5.Numerical simulation experiment shows that the development process of the water conducting fracture zone can be divided into four stages:gestation,occurrence and slow increase,sudden increase and stabilization.The water conducting fracture zone finally develops to the surface,reaching 165 m,and the mining-fracturing ratio is 27.5.With reference to the measured results of boreholes in the north of Ningtiaota Coal Mine,it is comprehensively determined that the mining-fracturing ratio of 2-2 coal in the south wing is more than 27.5.