中文摘要：

随着软岩大变形公路隧道支护体系中衬砌开裂、钢支撑扭曲、锚杆拉断等各种灾害问题的凸显，传统的强支护体系在大变形隧道处治中受到了极大的挑战，基于此，从围岩形变能合理释放、进而优化支护结构受力的这一思想出发，提出及时-强-让压支护的新型设计理念，并依据该设计理念提出基于让压锚杆＋可缩性钢拱架＋带变形槽或让压控制器的喷射混凝土组成的让压支护系统。以此支护系统为基础，结合杜家山公路隧道的大变形特征，对该体系中起始让压点及让压量等关键技术问题进行研究，结果表明：采用让压支护体系时，起始让压点越晚或让压量越大，围岩应变能释放越多，支护结构承受荷载亦即越小。但若让压量较小或起始让压点过早，则不能达到有效释放围岩形变能、改善支护结构受力的目的。若起始让压点过晚或让压量较大，虽充分释放了围岩位移，但因释放量过大而有可能导致围岩的破坏甚至塌方风险，故让压支护体系中起始让压点及让压量的设置应结合具体工程合理选择。

英文摘要：

With the outburst of various disasters in large deformation highway tunnel in soft rock,such as lining cracking, steel twisted and bolt broken, the traditional strong support system in the treatment of large deformation tunnel is now under great challenge. Considering the idea of releasing deformation energy and optimizing the structure stress, a new design idea named timely-strong-yielding support is presented in this paper. According to this design concept, the yielding support system that consists of yielding bolt, collapsible steel arch and sprayed concrete with deformable slot or pressure controller, was proposed. On the basis of this support system and the characteristics of large deformation of Dujiashan highway tunnel, this paper studied the key technical problems of the system, including yielding point, yielding amount and so on. The results shows that when using yielding sup-port, the later of yielding point, the more deformation energy will be released, and things are the same with more yielding amount. However, the purpose of releasing rock deformation energy and improving structure stress effec- 〈br〉 tively couldn＆#39; t be achieved if there is less yielding amount or earlier yielding point. More deformation energy would be released with greater yielding amount or later yielding point. On the other hand, the release of deforma-tion energy will result in surrounding rock failure even collapse. Therefore, the yielding point and the yielding a-mount shall be combined with specific engineering to help us to make reasonable choices.