巨高巷道帮不稳定三角块滑移及控制

 为解决超高巷道围岩控制难题，选取五家沟煤矿5201主运巷超高段(断面尺寸：5.25 m×8 m)为研究对象，采用UDEC和平衡拱理论分析帮不稳定三角块的响应特征。结果表明：(1) 帮受力状态如单侧无侧限单轴压缩，其破坏形式以侧壁夹角为45°－?/2方向上的三角块剪切滑移为主；(2) 帮深部垂直应力与水平应力差逐渐升高，构成帮不稳定三角块滑移的主要力源；(3) 帮沉降和水平位移曲线存在明显拐点，且拐点随巷高增加逐渐向深部转移；(4) 不稳定三角块最大宽度和顶压随巷高增加而增加，稳定性逐渐降低。认为：(1) 高性能、高预紧力锚杆可更好提高围岩力学性质，减小三角块顶压，保持帮不稳定三角块的完整性，帮中下部锚杆穿过主剪切滑移面可抵抗帮不稳定三角块的剪切滑移；(2) 斜拉锚索梁结构可发挥锚索抗拉强度大的优势，锚固在冒落拱迹线外的肩角和底角稳定区内，增大帮不稳定三角块滑移面的摩擦力。基于此提出高强高预紧力锚带网和帮斜拉锚索梁联合控制技术，掘出后顶底板相对最大移近速度4.1 mm/d，两帮相对最大移近速度4 mm/d，顶底板相对移近量104 mm，两帮相对移近量150 mm，顶板累计离层3.5 mm，支护完成后10 d实现自稳，帮不稳定三角块完整性好且无明显滑移迹象。

SLIP AND CONTROL OF COAL SIDE UNSTABLE TRIANGLE BLOCK IN SUPER-HIGH ROADWAY

To solve surrounding rock control problem in super-high roadway，the ultrahigh segment(section size is 5.25 m×8 m) of No. 5201 main transport roadway in Wujiagou mine was selected as research object. Response characteristic of coal side un-stable triangle block was analyzed by UDEC and balance arch theory. The results showed that：(1) Coal side force state is like unconfined uniaxial compression，the failure form is triangle block shear slip，whose angle is 45°－?/2 in the direction for lateral wall. (2) The vertical stress and the horizontal stress difference increases gradually in deep part，which constitutes main force source of un-stable triangle block slip. (3) Subsidence curve and horizontal displacement curve in coal side both have obvious inflections，which transfers to outside gradually with roadway height increasing. (4) Maximum width and roof pressure of un-stable triangle block add with roadway height increasing，stability gradually drops. It proves that：(1) High performance，high pre-stress bolt could enhance surrounding rock characteristics，decrease roof pressure and keep integrity of un-stable triangle block，and with middle and lower bolt in coal side pass through the shear slip face，also could resist shear and slip of un-stable triangle block. (2) Diagonal cable beam structure could be anchored in the shoulder and floor stable area out the caving arch，develope advantage of high strength，increases friction of un-stable triangle block. Based on this，the support technology of high strength and high pre-stressing bolt net bar and sides diagonal cable beam is proposed. During the period of driving influence，roof-to-floor relative convergent velocity is 4.1 mm/d，both sides maximal relative convergent velocity of sides is 4 mm/d，roof-to-floor relative convergence is 104 mm，both sides relative convergence is 150mm，the total roof separation was 3.5 mm，roadway self-stable period after it was dig out for 10 days，integrity of un-stable triangle block is well and slip sign is not obvious.