综采工作面顶板次生离层水害形成机理分析

Mechanism of water hazard caused by the secondary separation in the overburden stratum of the fully mechanized coal face

为了提高顶板离层水害防治效果,分析了离层水害形成的必要条件。采用力学分析的方法,结合关键层理论,推导出主采煤层覆岩中产生离层的判别式。研究表明:离层水害的形成取决于离层的形成、离层发育位置、离层补给水源和可积水离层空间持续时间。离层沿工作面推进方向的长度、离层发育高度、离层与煤层垂向距离、离层中心距工作面开切眼距离及工作面推进距离等5个参数确定了离层空间尺寸,该尺寸的大小控制了离层水的水量。以宁夏某煤矿综采工作面为例,分析了该矿顶板次生离层水形成的层位、储水空间大小。

To increase the effect of prevention and control of water hazard formed by overburden stratum separation,the necessary conditions for the formation of the hazard were analyzed.Combining the critical layer theory,a discriminant for the production of overburden stratum separation is deduced through mechanical analysis.The research results have shown that the formation of water hazard formed by overburden stratum separation depends on the appearance of the separation,the position of the separation,the source of water supply,and the duration of water standing in the separation space.The space size of the overburden stratum separation,which controls the water quantity therein,is determined by five parameters：the length along working face advance,the height of overburden stratum separation,vertical distance between separation and coal seam,the distance between the center of separation and open-off cut,and the length of working face.With a fully mechanized coal face of a coal mine in Ningxia Autonomous Region as an example,the stratigraphic horizon and the size of water-bearing spaces of separation were analysed respectively.