覆岩主关键层位置对导水裂隙带高度的影响

 采用理论分析、模拟实验和工程探测等方法，就覆岩主关键层位置对导水裂隙带高度的影响进行深入研究。研究结果表明：覆岩主关键层位置会影响顶板导水裂隙带高度，当主关键与开采煤层距离较近并小于某一临界距离时，顶板导水裂隙带将发育至基岩顶部，导水裂隙带高度明显大于按我国《建筑物、水体、铁路及主要井巷煤柱留设与压煤开采规程》(以下简称“规程”)中的顶板导水裂隙带高度确定方法得到的结果。对导水裂隙带高度产生影响的主关键层与开采煤层临界距离主要与煤层采高、顶板碎胀压实特性、主关键层破断块度等因素有关，可以粗略按7～10倍煤层采高计算该临界距离。当覆岩主关键层与开采煤层距离小于7～10倍采高时，不能按规程中的方法确定顶板导水裂隙带高度；当覆岩主关键层与开采煤层距离大于7～10倍采高时，仍可按规程中的方法确定顶板导水裂隙带高度。上述结果能很好地解释部分煤矿顶板异常突水灾害的发生机制，并指导神东矿区补连塔煤矿顶板突水灾害防治实践，取得显著的经济效益。

EFFECTS OF PRIMARY KEY STRATUM LOCATION ON HEIGHT OF WATER FLOWING FRACTURE ZONE

Theoretical analysis，simulation experiment and engineering exploration are adopted to study the impact of the location of primary key stratum(PKS) on the evolution range of water flowing fracture. The final result shows that，as the distance from PKS location to coal seam is shorter than a certain value，the fracture extends to the top of bedrock，while the height of water flowing fracture is obviously larger than its value calculated by the conventional estimation method based on “Regulations of buildings，water，railway and main well lane leaving coal pillar and press coal mining”(Regulations for short). The height of coal seam，the dispensability and compressibility of broken roof gangue，and the size of the broken block of PKS are the main evaluating factors of water-flowing fracture，which are concerned with the critical distance between PKS location and mining seam. The critical value can be generally concluded in the value 7–10 times as the height of coal seam. As the distance from PKS to coal seam is shorter than the critical value，the method based on the Regulations is unreasonable；as the distance from PKS to coal seam is larger than the critical value，the method based on Regulations is available. Therefore，the above research result is the certain explanation to the mechanism of irregular water inrush accident in some coal mines. The achieved results have been employed to conduct the water inrush protection in Bulianta coal mine，Shendong coal field；meanwhile，the significant benefits have been obtained.