二次采动下沿空留巷围岩变形及其控制研究

针对二次采动下沿空留巷围岩变形控制困难问题，揭示了沿空留巷围岩变形规律，建立了二次采动下沿空留巷围岩变形力学模型，推导出了围岩变形的理论公式，据此分析了围岩变形的影响因素，提出了支护对策，并进行了工程实践。结果表明:围岩变形理论公式与现场实测值基本一致；顶底板移近量以底鼓为主，底鼓量为直接底压曲量与老底挠曲量的最大值；各因素对围岩变形影响程度依次为巷旁支护体宽度、迭加应力集中系数、采高、采深、老底弹性模量。围岩变形控制对策应围绕关键性影响因素进行，据此提出“锚网索+高强度墩柱+老底注浆”耦合支护对策，工程实践表明，沿空留巷围岩变形稳定，得到了有效控制。

Deformation of surrounding rock and its control of gob-side entry retaining during the second mining stage

Aiming at the problem of difficult controlling on surrounding rock deformation of gob-side entry retaining during the second mining stage, the deformation laws of surrounding rock of gob-side entry retaining were revealed, and a mechanics model on surrounding rock deformation of gob-side entry retaining during the second mining stage was established. The theoretical formulas of surrounding rock deformation were deduced, and the influencing factors of surrounding rock deformation were analyzed. The support countermeasures were proposed and put into practice. The results showed that: the outcome of theoretical formulas of surrounding rock deformation was in general accord with that measured in field. The floor heave accounts for most of displacement from roof to floor, and the quantity of floor heave is the maximum value of direct floor buckling and hard floor deflection. The influence extent of each factors to surrounding rock deformation was sorted as width of supporting body on entry side, superposition stress concentration coefficient, mining height, mining depth, elastic modulus of hard floor, direct roof thickness and support resistance in entry. The control countermeasures of surrounding rock deformation should be performed according to the key influence factors. The control countermeasure of "bolt-net-anchor + high strength pier + hard floor grouting" coupling support was put forward. The engineering applications demonstrated that the surrounding rock deformation of gob-side entry retaining during the second mining stage was stable and controlled effectively.