浅埋煤层覆岩关键层结构分类

Classification of key strata structure of overlying strata in shallow coal seam

以神东矿区浅埋煤层开采为工程背景,对浅埋煤层覆岩关键层结构的类型及其破断失稳特征进行了研究.结果表明,浅埋煤层覆岩关键层结构类型可分为单一关键层和多层关键层结构;单一关键层结构又分为厚硬单一关键层结构、复合单一关键层结构、上煤层已采单一关键层结构3种类型.单一关键层结构是导致浅埋煤层特殊采动损害现象的地质根源,浅埋煤层单一关键层结构采动破断运动不仅对工作面矿压产生影响,同时会影响顶板涌水溃沙和地表沉陷.关键层破断块体结构承担的载荷层厚度大而不能满足砌体梁结构不发生滑落失稳的条件,从而导致关键层破断块体滑落失稳,这是导致神东矿区浅埋煤层单一关键层结构工作面易出现台阶下沉和压架出水等采动损害问题的力学机理.确定了神东矿区浅埋煤层覆岩关键层结构类型的判别方法.

Based on the engineer background of shallow coal seam extracted in Shendong coal field in China, both the structure type and the breakage and unbalance character of overburden key stratum （KS） were studied as the condition of shallow coal seam. The results show that the structure type of overburden KS can be classified into four groups within two types, single KS structure and multi-KS structure. Single KS structure is divided into thick-rigid group, compound group and over seam extracted group. The unbalance of single KS structure is the geologic season to the unusual mining subsidence phenomenon as in shallow coal seam, and its breakage process not only engenders huge effect to underground pressure around work face but also causes the water or sand rush from the roof and the surface subsidence. The block structure formed by the breakage of KS bears too much self-load to come to the sliding criteria of voussoir beam, so that the blocks slide down and the structure is unbalanced, which is the dynamic mechanism of frequent sidestep subsidence, water and sand rush, and mechanized supports crushing happened around workface covered by single KS in shallow coal seam extracted in Shendong coal field. The distinguishing method of overburden KS types in shallow coal seam extracted in Shendong coal field was defined.