远距离下保护层开采上覆煤岩层采动应力场数值模拟研究

Numerical simulation research on mining stress field of overlying coal-rock seam under far distance lower protective seam mining

为了研究开采下伏8号煤层能否缓解赵庄煤矿主采3号煤层开采过程中的强矿压显现问题,采用FLAC^(3D)软件模拟远距离下保护层开采方案,分析了下保护层8号煤层开采前后被保护层3号煤层采掘过程中的应力峰值、应力分布及塑性范围。结果表明,随着下保护层8号煤层工作面的推进,被保护层3号煤层工作面在倾向上的应力整体呈"M"型分布,煤体两端呈现应力集中,中部区域应力较低,使布置于中部卸压区的3号煤层工作面巷道围岩产生不同程度的卸压;下保护层8号煤层开采后,被保护层3号煤层工作面的煤体应力峰值减小约18%,采动影响距离减小约10m,且应力集中程度减弱,工作面煤体基本未出现新的塑性区域。

In order to research the problem that mining underlying No.8 coal seam can alleviate strongstrata behavior during mining No.3coal seam or not,a far distance lower protective seam mining scheme was simulated by use of FLAC^3D software,and stress peak value,stress distribution and plastic range were analyzed during mining process of the protected No.3 coal seam before and after mining the lower protective No.8 coal seam.The research results show that with the lower protective No.8 coal seam advancing,inclined stress of working face of the protected No.3 coal seam represents ＂ M＂ shape,namely both ends of coal body shows stress concentration,and stress in middle region is lower,so as to make surrounding rock of the No.3 coal seam working face roadway,which is arranged in central pressure relief area,get pressure relief with different degree.After mining the lower protective No.8 coal seam,the stress peak value of the protected No.3 coal seam working face is reduced about 18%,and mining influence distance is shorted about 10 m.Meanwhile,stress concentration degree is weakened,and new plastic zone does not appear in coal body of the working face.