为了解决西部矿区中生代软岩特大型硐室的围岩控制难题,以沙吉海煤矿皮带卸载硐室工程为研究对象,采用现场调研、室内试验、数值计算及现场试验相结合的方法,研究了硐室的变形破坏机理及控制对策.结果表明:硐室断面特大、围岩自承能力不足、膨胀及松动压力高、支护设计及施工存在缺陷是围岩变形破坏的主要原因.应用软岩工程力学理论,确定了围岩IAIIBCDIIIE复合型变形力学机制.基于恒阻让压、刚柔并济、协同控制的支护理念,合理地将复合型变形力学机制转化为单一型,并提出了"恒阻大变形锚杆(索)+离壁U型钢架+底角锚管注浆+浇筑砼"的控制对策.工程实践表明该对策有效控制了特大型软岩皮带卸载硐室的变形,保证了工程稳定,应用效果良好.%In order to solve problem on the surrounding rock control for extra-large chamber in Mesozoic soft rock in western mining area, taking the belt unloading chamber engineering in Shajihai coal mine as research object, the methods of field investigation, laboratory test, numerical calculation and field test were used, and con-trol strategies and failure mechanism of chamber were studied. The results shows that the main reasons for defor-mation and failure of surrounding rock are extra-large section, insufficient self-bearing capacity, high expansive and loose pressure, defects with support design and construction. The mechanics mechanism of surrounding rock deformation is determined as composite type, i.e., IAIIBCDIIIE type through mechanics theory of soft rock engi-neering. Based on the supporting philosophy of constant resistance with yielding, combination of softness and hardness, and cooperative control, the compound mechanics mechanism is reasonably transformed into some sin-gle types, then the control measures with "constant resistance with large deformation bolt (cable) & U shaped steel frame off wall & bottom anchor pipe with grouting & pouring concrete" are put forward. The engineering practice shows that the measures can effectively control the deformation of the super large soft rock chamber for belt unloading, which ensured stability of the project, and the application effect is good.
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