煤柱下极近距离特厚煤层沿空掘巷合理位置确定研究

Research on Determination of Gob-side Entry of Close-distance Extrathick Coal Seam under Coal Pillars

合理的巷道位置是煤柱下极近距离特厚煤层沿空掘巷成功的关键。针对中煤塔山煤矿特厚煤层沿空巷道大变形、支护体失效等强矿压显现问题,采用极限平衡理论、FLAC3D数值模拟及现场实测等方式,研究煤柱下极近距离特厚煤层沿空掘巷的合理位置。结果表明:沿空掘巷在上覆煤柱下位置不合理是造成塔山沿空掘巷大变形的主要原因;由于上覆煤柱的作用导致下伏岩层内产生了应力集中,并且随着测点距煤柱水平距离增加,应力集中程度迅速降低;塔山沿空掘巷段煤柱宽度小于5 m时,煤柱垂直应力呈三角形分布;煤柱宽度为8~10 m时,应力呈梯形分布;煤柱宽度大于10 m时,应力呈马鞍形分布;经过对比塔山煤矿选择8 m煤柱能满足工程要求。研究结果可为类似条件下沿空掘巷合理位置的确定提供理论依据和工程参考。

The reasonable location of the roadway is the key to the success or failure of roadway excavation along the goaf in a short distance and extra-thick coal seam under the coal pillar.Aiming at the emergence of strong underground pressures such as large deformation of the roadway along the goaf in the 15 m extra-thick coal seam of China coal Tashan coal mine,failure of supporting bodies,etc.,the method of limit equilibrium theory,FLAC3D numerical simulation and field measurement are used to study the short distance and extra thick coal seam under the coal pillar reasonable location of the tunnel.The results show that:the unreasonable location of the roadway along the gob under the overlying coal pillar is the root cause of the large deformation of the roadway along the gob in Tashan;the overlying coal pllar has caused stress concentration in the underlying rock,as the horizontal distance between the measuring point and the coal pillar increases,the degree of stress concentration decreases rapidly;when the protection coal pillar of Tashan roadway driving along the goaf is less than 5 m,the stress on the coal pillar appears triangular distribution;when the width of the coal pillar is between 8 m and 10 m,it presents a trapezoidal distribution;when the coal pillar width is greater than 10 m,it presents a saddle-shaped distribution;after comparing with Tashan,choosing 8 m coal pillar can meet the engineering requirements.The research results can provide theoretical basis and engineering reference for driving along goaf under similar conditions.