断裂结构面对回采工作面矿压及顶板稳定性的影响

Influence of fracture structure plane on underground pressure and roof stability of working face

通过对现场观测和数值模拟分析，系统研究了断裂结构面对回采工作面矿压分布和顶板稳定性的影响。研究结果表明，回采工作面顶板断裂结构面有3种典型组合类型，即“正三角形”结构、“川字形”结构和“倒三角形”结构。在工作面开采过程中，“正三角形”结构顶板稳定性差；“倒三角形”结构顶板稳定性好；而“川字形”结构顶板能形成结构平衡且稳定。由于断层使介质不连续，导致初始应力场挠动，局部产生附加应力，在断层带附近形成低压力区和高应力集中区带，比较明显的影响范围距断层面大约10-30m。当工作面推进到高应力集中区带时，工作面前方煤（岩）体中支承压力明显增大，支承压力峰值位置向前方煤岩体中转移，易于发生冒顶事故和其他矿井动力地质现象；当工作面推进到低应力区带时，压力峰值降低，顶板稳定性差。

By using field observation and numerical simulation method, the influence of fracture structure plane on the underground pressure and the roof stability of working face are systematically studied. The research results show that the fracture structure plane of coal roof has three kinds of typical combination styles, namely ＂regular triangle＂ structure, ＂Ⅲ shape＂ structure and ＂inverted triangle＂ structure, During coal mining, the coal roof of ＂regular triangle＂ structure is unstable, but the ＂inverted triangle＂ structure is stable and the roof of ＂Ⅲ shape＂ structure is able to form structure equilibrium and reaching stability. Because of fault inducing medium discontinuous and changes of initial stress field and additional stress in some areas, there are the low stress area and high stress concentration zone in the fault and its surrounding zone, the much obvious effect range is about 10 ～ 30 m far away the fault surface. In the high stress concentration zone of fault, the abutment stress in front of working face increases obviously and the peak value position of abutment stress migrates to the inside of coal mass with reduction of distance away from the fault. In the zone, the roof accident and other dynamic phenomenon are prone to happen. In the low stress zone of the fault, the strength of coal and rock is lower, the abutment stress decreases and the stability of coal roof is weak.