目前大变形隧道的有效支护成为了地下工程中必须面对的一个问题。在隧道发生大变形的条件下，采用普通的锚杆支护方法，不仅工程成本上升，而且支护效果差，甚至出现锚杆支护体系失效的现象。而预应力锚索具有初锚力高，杆体强度高，锚固长度大，对围岩条件依赖性低的特点，是一种主动支护手段。故探索大变形隧道的预应力锚索支护方法，有效控制隧道的变形，具有重要的工程实际意义。 本文在已有的理论基础上，对大变形隧道预应力锚索支护技术进行了深入研究，具体的研究内容与取得的主要研究成果如下： （1）对大变形隧道围岩变形特征进行深入分析后认为，大变形隧道的形成主要原因是围岩的挤出和膨胀，且挤出起主导作用；大变形隧道围岩破坏的主要特征是隧道开挖后径向收敛变形量大，围岩支护前期自稳时间短，塑性破坏范围大；影响隧道发生大变形的主要因素是隧道所处位置的地质结构，地应力大小及围岩自身的物理力学性质； （2）对预应力锚索支护机理进行了深入分析后认为预应力锚索可有效控制大变形隧道的收敛位移，并改善围岩的应力状态，并基于岩石力学中的弹塑性理论，在考虑预应力锚索预紧力损失，锚索锚固段剪应力非均匀分布及锚固剂的摩擦角对锚固效果的影响前提下，提出了预应力锚索支护参数的计算公式，并通过算例进行了验证； （3）借助FLAC3D模拟软件，分析了预应力锚索的间距、直径、预紧力大小的变化对埋深750m，洞径6m，围岩条件为V级的大变形隧道位移控制的影响后认为，预应力锚索参数中对大变形隧道位移的控制起主要作用的参数是锚索的间距和预紧力；然后对这两个参数和喷射混凝土参数（强度等级和厚度）分别进行两两正交组合优化后认为，预应力锚索支护最优参数是：间距为1.1m，钢绞线根数为4根，钢绞线规格为φ15.24强度1860MPa的钢绞线、长度为20m，预紧力大小为369kN；喷射混凝土最优参数是：强度等级为C25，厚度为25cm。

With the traffic construction having the higher requirement of road line features and the quantity of the long tunnel has the continuous increasing; the effective support for the tunnel with large deformation is one of the issues which underground engineering must face. With the tunnel with large deformation, if the supporting method is normal bolt supporting, it will make the project cost rising, the bad supporting effect, and even bolt supporting system is failure. While, the prestressed anchor cable support is the active support method, because it has lots of advantages, such as high anchorage force, long anchorage length, and low dependence to surrounding rock. Therefore, it is urgent to seek the prestressed anchor cable support methods of the tunnel with large deformation, which can effectively control the displacement of the tunnel and ensure long-term security and stability of tunnel, which has important practical significance. Base on the related researches, the prestressed anchor cable support technique for the tunnel with large deformation is studied in this paper. The concrete research contents and main achievements are as follows: (1)Deeply analyze the deformation features of surrounding rock mass of the tunnel with large deformation, obtain the results as follows: The most important factors of forming the tunnel with large deformation are the expressing and expanding of the surrounding rock mass, and the expressing of the surrounding rock mass often leads the tunnel to form the large deformation; The most important features of the destroying of the surrounding rock mass of the tunnel with large deformation are the large radial deformation is formed after the excavation of tunnel, the steady period of tunnel is short when the supporting of the tunnel is finished just recently and the plastic region of the rock mass is large; The most important factors which affect the large deformation tunnel to form are geological structure, ground stress and mechanical properties of rock mass. (2)Deeply analyze the support mechanism of prestressed anchor cable, the result is prestressed anchor cable can effectively control the large deformation of the tunnel and improve the stress status of surrounding rock mass. Then basing on elastic-plastic theory of rock mechanics, put forward the calculation equations of the supporting parameters of prestressed anchor cable by considering the prestressing loss of the prestressed anchor cable, the non-uniform distribution of the shearing stress of anchorage segment of the cable and the influence caused by the internal friction angle of anchor agent to the anchorage effectiveness. Then proving these calculation- equation correctness by the calculation example. (3)By using the software FLAC3D, the influences caused by changing the parameters of prestressed anchor cable such as interpretable spacing, diameter and prestressing force to the displacement of the tunnel with large deformation which depth is 750m，diameter is 6m，surrounding rock mass intensity degree is five are analyzed. Then determine the interpretable spacing and prestressing force are the parameters of the prestressed anchor cable which mainly control the displacement of the tunnel. Finally, optimize the parameters of prestressed anchor cable which mainly control the displacement of the tunnel with large deformation by orthogonally combine them. Then optimize the parameters of shotcrete, which are the strength grade and thickness, by orthogonally combine them. Finally, basing on the tunnel with large deformation, obtain the optimal prestressed anchor cable and shotcrete parameters. The optimal prestressed anchor cable parameters are interpretable spacing is 1.1m, the number of roots of teel strand which the diameter is 15.24mm and strength 1860MPa is four, the length is 20m, the prestressing force is 369kN. The the optimal shotcrete parameters are the strength grade is C25, the thickness is 25cm.