中厚煤层窄煤柱沿空掘巷围岩稳定性研究

Surrounding rock stability during gob-side entry driving with narrow coal pillar in medium-thick coal seam

以恒源煤矿487工作面窄煤柱沿空掘巷为工程背景,基于该矿工程实况采用理论计算、数值模拟等手段综合确定487工作面回风巷最优护巷煤柱宽度为5m;基于数值模拟分析了487工作面回采后沿空掘巷超前段顶板、实体煤以及煤柱内围岩应力分布、围岩变形与塑形区演化特征,针对性提出了高强锚杆索组合非对称支护技术,并分析了巷道支护应力场的合理性。工程实践表明:工作面回采动压影响下沿空掘巷围岩剧烈扰动范围存在于超前工作面30m内,顶底板及两帮移近量最大分别为574mm、759mm;超前工作面30m后巷道围岩变形趋于稳定,顶底板及两帮移近量平均分别为190mm、315mm,5m护巷煤柱和高强锚杆索组合非对称支护技术有效控制了沿空掘巷围岩变形。

Based on the engineering background of gob-side entry driving with narrow coal pillar in 487 working face of Hengyuan Coal Mine,the optimal roadway pillar width of tailgate in 487 working face is determined to be 5 m by means of theoretical calculation and numerical simulation.Based on numerical simulation,the stress distribution,surrounding rock deformation and plastic zone evolution characteristics of roof,solid coal and coal pillar in advance roadway after mining in 487 working face are analyzed.The combined asymmetrical support technology with high-strength bolt and cable is proposed,and the rationality of roadway support stress field is analyzed.The engineering practice shows that,under the influence of mining dynamic pressure the surrounding rock of gob side entry is disturbed severely by the working face within 30 m of the advance working face.The maximum displacement of roof and floor and side walls are 574 mm and 759 mm,respectively.The of deformation surrounding rock tends to be stable after 30 m ahead of working face,the average roof-to-floor convergence and side-wall convergence are 190 mm and 315 mm separately,which means the 5 m coal pillar and bolt-cable combined asymmetric support technology can control the surrounding rock deformation in gob-side entry driving.