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为解决厚煤层大断面切眼支护难题,选取某煤矿5206切眼为研究对象,采用UDEC模拟研究了切眼宽度为6~10 m的过程中,围岩主应力差、变形、裂隙场的响应特征,结果表明:顶、底、两帮主应力差分布形态均呈浅部逐渐升高、深部降低特征;随着切眼宽增加,顶板主应力差峰值呈先恒定后降低,底板主应力差呈先降低再恒定,而两帮主应力差逐渐升高的趋势;主应力差峰值向深部转移幅度:两帮>顶板>底板。顶板和两帮深部位移曲线呈指数关系向深部递减,而底板深部变形曲线有明显拐点,呈台阶式降低,表面最大位移呈顶板>两帮>底板;围岩裂隙场分3个区:裂隙贯通区、裂隙发育区、微裂隙区,半椭圆状分布,裂隙贯通程度呈中间大于两侧、浅部大于深部。认为:高性能锚杆可以更有效地限制裂隙滑移,双桁架锚索可锚固在顶板肩角无裂隙区和深部预应力叠加区,可有效加强支护顶板,抵消部分主应力差。基于此,提出了高强、高预紧力锚带网和双桁架锚索联合控制技术,支护完成后10 d自稳,顶板累计离层3 mm,顶底板相对移近量125 mm,两帮相对移近量94 mm。
In order to solve the problem of large cross-section cut support in thick coal seam, 5206 cut eyes of a coal mine are chosen as the research object. The UDEC simulation is used to study the main stress difference, deformation and fracture field of surrounding rock in the process of 6-10 m cutting width The results show that the distributions of the principal stress differences of the top, bottom and the two groups all gradually increase in the shallow part and decrease in the deep part. As the width of the cut eye increases, the peak value of the principal stress difference of the top plate decreases first and then decreases, First decreased and then constant, while the two main stress gradually increased the trend; the main stress difference to the depth of the peak transfer rate: two gangs> roof> floor. The top plate and the two deep displacement curves decrease exponentially to the depth, while the bottom plate deformation curve has a significant inflection point, which is stepped down. The maximum displacement of the top plate is the top plate> two gangs> bottom plate. The fractures of the surrounding rock are divided into three zones: Zone, fissure development zone, micro-fissure zone, semi-elliptical distribution, fissure penetration is greater than the middle of the two sides, shallow greater than the deep. It is considered that the high performance anchor rod can limit the slippage of slips more effectively, and the double truss anchor cable can be anchored in the no crack zone and the deep prestressed superposition zone at the roof shoulder angle, which can effectively reinforce the supporting roof and offset some of the main stress difference. Based on this, a joint control technology of high strength and high prestressing anchor net and double truss and anchor cable is proposed. Self-stabilization is achieved 10 days after the support is completed. The cumulative total roof separation is 3 mm, the relative displacement between roof and floor is 125 mm, Relatively close to the amount of 94 mm.