采动应力效应下的煤层底板裂隙演化规律研究

煤层底板突水的实质是采动应力诱发煤层底板裂隙失稳、扩展和贯通,形成突水通道,进而引发突水灾害。根据回采工作面前后支承压力分布规律,笔者建立了煤层底板应力计算模型,分析了随着回采工作面的推进煤层底板中的垂直应力和水平应力分布规律以及煤层底板的破坏形式;对煤层底板岩体进行了破坏分区,根据断裂力学理论给出了不同区域内,裂纹不同破坏模式下的张开位移表达式;采用震波检层技术验证了煤层底板采动裂隙动态的演化规律,有利于煤矿底板突水预测和突水防治措施的制订。

Research on Evolution Rules of Coal Seam Floor Crack under Mining Stress Effect

The essential of coal floor water-inrush is a kind of disaster induced by instability, extension and penetration of floor crack due to mining stress. According to distribution rules of abutment pressure of coal face, a coal floor stress calculation model was established which was used to analyze the vertical and horizontal stress distribution and failing forms of the coal floor during working face advances. Based on classifying zones of crack failure, the opening displacement expression in different zones and under different failure modes of the crack is given according to fracture mechanics theory. The rules of the coal seam floor mining-induced fractures dynamic evolution are verified by the shock wave inspection layer technology. The research result is helpful for coal floor water inrush forecast and water inrush prevention and control measures development as well.