基于PFC的覆岩破坏高度数值模拟及实测分析

Numerical simulation and actual measurement analysis of overburden failure height based on PFC

为了直观、清晰地掌握煤层开采覆岩裂隙发育演化情况,确定覆岩破坏高度,归纳相对应的演化规律,以伊犁矿区为试验研究对象,采用离散元颗粒流软件PFC 3D建立数值模拟三维模型,依据现场测得的宏观参数,模拟工作面推进160 m时各煤层采高范围覆岩破坏情况,并采用钻孔实时彩色成像技术对PFC 3D模拟情况进行全面验证。研究结果表明:煤层采高与上覆岩层垮落强度呈正相关关系,煤层采高越大,上覆岩层垮落高度越大,上覆岩层垮落发生时期基本相同,垮落强度有所增加;PFC 3D模拟显示覆岩内部裂隙以竖向裂隙为主,其裂缝倾角达到50°以上,而且具有高角度直逼垂直岩层层面裂隙的发育特点。

In order to intuitively and clearly grasp the development and evolution of overburden rock fractures in coal mining,determine the failure height of overburden,and conclude the corresponding evolution law,taking Yili mining area as the experimental research object,using discrete element particle flow software PFC 3D to establish the three-dimensional model of numerical simulation,according to the macroscopic parameters measured on site,simulating the damage of the overburden rock in each coal seam when the working face is advanced 160 m,and adopting real-time color TV imaging technology of drilling to fully verify the PFC 3D simulation.The research results show that:the coal seam mining thickness has a positive correlation with the overburden collapse strength,the greater the coal mining thickness,the greater the overburden collapse height,the overburden collapse occurs during the same period,and the collapse intensity increase;PFC 3D simulation shows that the internal fissures in the overburden are mainly vertical fissures,and the inclination angle of the fissures has reached more than 50°,and the fissure development characteristics with a high angle close to the vertical rock layer.