特厚煤层综放工作面沿空掘巷小煤柱留设与支护研究

Research on the Setting and Support of Small Coal Pillars in the Driving Roadway Along Goaf of Fully Mechanized Caving Face in Extra Thick Coal Seams

为研究特厚煤层综放工作面沿空掘巷留设小煤柱的合理宽度,以塔山煤矿8117工作面回风巷为研究对象,采用理论计算、数值模拟和现场实测相结合的研究方法进行研究。研究表明:相邻工作面采空区稳定后煤体侧向支承应力降低区范围为0~13.7 m,煤柱宽度在8 m以下可确保8117工作面回风巷处于应力降低区,有利于巷道围岩的稳定;煤柱宽度大于8 m时,煤柱内弹性区随煤柱宽度的增加而增大,煤柱中部垂直应力开始超过原岩应力;最终确定采用8 m小煤柱。现场观测表明,留设8 m煤柱时,8117回风巷在掘进和回采阶段巷道两帮移近量和顶底板下沉量较小,煤柱可以有效支撑顶板、控制围岩变形。

In order to study the reasonable width of small coal pillars setting in the driving roadway along goaf of the fully mechanized top coal caving face in extra thick coal seams,the return air roadway of the 8117 working face of Tashan Coal Mine is taken as the research object,and a combination research method of theoretical calculation,numerical simulation,and on-site measurement is used for research.The research shows that after the adjacent working face goaf is stabilized,the range of the lateral support stress reduction zone in the coal body is 0 to 13.7 m,and the width of the coal pillar below 8 m can ensure that the return air roadway of the 8117 working face is in the stress reduction zone,which is conducive to the stability of the surrounding rock of the roadway;When the width of the coal pillar is greater than 8 m,the elastic zone inside the coal pillar increases with the increase of the coal pillar width,and the vertical stress in the middle part of the coal pillar begins to exceed the original rock stress;The final decision is to use an 8 m small coal pillar.The on-site observation indicates that when an 8 m coal pillar is set,the displacement amount of the two sides of the roadway and the subsidence amount of the roof and floor of the 8117 return air roadway are relatively small during the excavation and mining stages.The coal pillar can effectively support the roof and control the deformation of the surrounding rock.