关键层对煤层群开采瓦斯卸压运移“三带” 范围的影响

采用相似模拟、数值模拟和理论分析的方法，就覆岩关键层对煤层群开采瓦斯卸压运移“三带”范围的影响进行深入研究。研究结果表明：覆岩导气裂隙带内是否存在关键层将对覆岩瓦斯卸压抽采范围起到十分明显的影响作用。在相同开采条件下，覆岩裂隙带内存在关键层时，该关键层的破断将引起导气裂隙带高度突增，其高度明显高于经验公式计算高度并止于该关键层上方另一层关键层之下；卸压解吸带高度止于覆岩中尚未发生破断且下方存在离层空间的关键层之下，其最大高度止于主关键层之下。

Effects of key stratum on the scope of the "three zones" of gas pressure relief and migration in coal seam group mining

Similar material physical simulation and numerical simulation and theoretical analysis were adopted to study the impact of key stratum on the scope of the “three zones” of gas pressure relief and migration in coal seam group mining.The results show that，whether there exists a key stratum within the overlying gas conductive fracture zone will obviously affect the scope of the “three zones” of gas pressure relief and extraction.In the same mining conditions，if there exists a key stratum within the fracture zone of overlying strata，the failure of the key stratum will lead to an uprush in the height of gas conductive fracture zone，which is higher than empirical formula result，and the gas conductive fracture zone height will reach the bottom of the upper key stratum.Gas pressure relief and desorption zone develops to the unbroken key stratum under which exist much bed separation space，and its maximum height reaches the bottom of the primary key stratum.