顶强帮弱半煤岩巷道围岩变形特性及控制对策

Deformation properties and control measures of surrounding rock in strong roof and weak wall semi coal-rock roadway

针对“顶强帮弱”半煤岩巷道巷帮围岩塑性破坏范围大、锚杆支护强度不足等围岩控制难题,以某矿8#煤层回采巷道为工程背景,在围岩力学性能测试、钻孔可视化观测及声波法实测巷帮不同高度松动圈的基础上,对该类巷道围岩的力学及宏观变形特征进行了研究,得出巷帮煤层既是影响巷道整体稳定的“短板”,又是支护的“关键”。建立数值模型分析了“顶强帮弱”半煤岩巷道围岩受采动影响的变形特征、应力分布规律及承载特性,提出了强化帮部薄弱部位的围岩控制对策,并进行了工业性试验。结果表明:对“顶强帮弱”半煤岩巷道帮部煤层采用“锚杆+斜拉穿层锚索+强护表构件”的支护对策可使其处于三向压缩受力状态,约束其向巷道内挤出变形,发挥封闭及主动促稳作用。

Aiming at the difficulties of large plastic failure range of surrounding rock and insufficient strength of bolt support system of the“strong roof and weak side”semi coal-rock roadway,taking 8#coal seam mining roadway of a certain mine as the engineering background,based on the test of surrounding rock mechanical performance,visual observation of drilling and loose zone test at different lane heights,the surrounding rock mechanics and macroscopic plasticity of the roadway are summarized.It is concluded that the coal seam of the roadway is not only the weakest point affecting the overall stability of the roadway,is also the most important part of supporting.By establishing numerical analysis model,deformation and bearing characteristics,stress distribution of surrounding rock of this kind of roadway are analyzed.The surrounding rock control measures for strengthening the weak part of the wall are proposed and carried out.The results show that the support measures of“bolt+tilted and crossing layer cable+strong protective surface component”can make the coal seam placed in a triaxial state of stress,restrained its extrusion deformation,and exerted an active stabilizing effect.