倾斜特厚煤层综放带压开采底板破坏特征研究

Failure characteristics of floor under predssure inclined and extra thick coal seam in full-mechanized top coal caving faces

采动底板破坏特征，对于带压开采具有重要意义。以文明矿为试验矿井，采用分段注水装置、钻孔电视系统、地质雷达对大采深特厚倾斜煤层综放开采底板破坏深度进行探测，并对采动前后底板裂隙数量与钻孔深度、裂隙宽度与数量进行数字化分析，并就采动后底板应力变化和塑性区特征进行数值模拟试验，数据结果表明：文明矿大采深倾斜特厚煤层综放开采底板破坏深度为30．1m；采动前裂隙数量较小，而采动后裂隙数量呈上升～下降一不变的形态分布；采动前底板裂隙宽度以小于5mm为主，采动后裂隙宽度以16--20mm为主；工作面下方支承压力集中系数大于上方；底板垂直应力曲线在倾斜方向上呈“勺形”分布且卸压程度随着底板深度增加而逐渐降低并形成了较大的塑性破坏区。

Characteristics of floor failure is very significance for mining under pressure. Taking Wenming coal as the experimental mine, by using the equipment which is sealed two ends by capsules in borehole, affused measurable water between the two capsules and borehole televiewer system and ground penetrating radar, height of floor under large mining depth inclined and extra thick coal seam in fully-mechanized top coal caving face is monitored and analyzed through the digital relationship of fractures around mining such as numbers and depth, numbers and width. At the same time, numerical model experiment of stress change and characteristic of plastic zone are carried out. The results show that： （1） Height of floor under large mining depth inclined and extra thick coal seam in fully-mechanized top coal caving face is 30.1 m; （2） The fracture width is mainly with less than 5 mm before mining and the fracture width is mainly 16 - 20 mm after mining; （3） The number of fractures is small before mining, with the mining of working face, the number of fractures is on a rising-down-invariant trend： （4） The abutment pressure concentrated coefficient of working face inferior is greater than the above~ （5） Floor verticalstress curve on the tilt direction distribution is ＂spoon＂ shapes, with the depth of floor increased the pressure release level is decreased and to form the large plastic failure zone.