倾角对煤岩组合体力学及冲击倾向性影响的颗粒流分析

摘要

With the increase of coal mining depth,the interaction between coal seam and top and bottom rock layer is more obvious.This paper establishes the rock-coal numerical model of “roof-coal” structure based on the particle discrete element program PFC,and the influence of 0°,15°,30°,45°,60° dip angle on failure mode and impact tendency of composite body are studied.The macroscopic fracture of the composite is basically a shear crack of type V,and the damage mainly concentrates on the part of the coal,and the ends of the V coincide with the interface of the model.With the increase of dip angle,there are the more active particles,especially when the dip angle of the composite is greater than 45°,and the displacement and activity of the particles at the interface of coal and rock are the biggest.With the increase of dip angle,the impact energy index of the composite body decreases gradually,especially when the inclination angle is greater than 45°,the impact energy index decreases greatly.%随着煤矿开采深度的增加,煤层与顶底板岩层的相互作用更加明显.基于颗粒离散元程序PFC建立了“顶板-煤层”结构的“岩-煤”数值模型,通过设定煤岩交界面的倾角分别为0°、15°、30°、45°、60°,研究了不同倾角对组合体破坏模式及冲击倾向性的影响.研究结果表明,组合体的宏观破坏裂纹基本上呈“V”型的剪切裂纹,破坏主要集中于煤体部分,且“V”型破坏面的两端与煤岩交界面的两端重合;随着倾角的增大,活跃的颗粒数量越多,尤其当组合体倾角大于45°时,煤岩交界面处的颗粒位移量和活跃程度最大;随着倾角的增大,组合体的冲击能量指数逐渐减小,尤其当倾角大于45°时,冲击能量指数大幅度减小.