不同倾角隐伏断层条件下的底板突水模拟研究

Simulative Study on Floor Water Bursting in Conditions of Buried Fault with Different Dip Angles

为了揭示不同倾角隐伏断层条件下的底板突水机理,运用剪切破坏理论建立了隐伏断层导水机理的力学模型。根据某实际矿井地质条件构建了倾角分别为15°、30°、45°、60°和落差为3m的隐伏逆断层模型,运用FLAC3D数值模拟方法分析了不同倾角隐伏逆断层在开采条件下的塑性区、垂直应力、孔隙水压力分布情况。结果表明:承压水的理论极限值受工作面埋深、采高、隐伏断层产状及其与底板距离等因素的影响,其中隐伏断层倾角的影响最为显著。当断层倾角较大、且与塑性区相交后断层下盘就会发生大面积破坏,破坏深度可达到23m;当隐伏断层靠近底板破坏区或完全位于采空区下方,隐伏断层末梢垂直应力大幅度降低,且沿断层方向岩层应力也大幅下降;孔隙水压力的压差高度随着隐伏断层倾角的增大而逐渐减小,但底板孔隙水压力的变化趋势则相反,隐伏断层上端末梢的揭露位置越靠近切眼,其孔隙水压力值越大,对开采工作影响越大。

To reveal floor water bursting mechanism under conditions of buried fault with different dip angles,through shearing failure theory has established a buried fault water conduction mechanism mechanical model.On the basis of a real mine geological condition has established buried reverse fault model with dip angles 15°,30°,45°,60°and throw 3m,using FLAC3D numerical simulation analyzed different dip angle reverse faults plastic zone,vertical stress,pore water pressure distribution under mining condition.The result has shown that confined water theoretical extreme is impacted by factors of working face depth,shear height,buried fault occurrence and its distance to floor,in which,the impact from buried fault dip angle is most distinctive.When the dip angle is larger and intersected with plastic zone,fault footwall will be happened large area failure;the failure depth can be up to 23m.When buried fault close to floor failure zone or totally under gob area,its distal vertical stress will be considerably reduced,and stress in strata along the fault direction the same.Pore water pressure differential height will be gradually reduced along with buried fault dip angle increasing,but floor pore water pressure variation trend on the contrary.The revealed position of buried fault upper distal end would be the closer to open-off cut,the larger the pore water pressure,and the larger the impact from mining.