让压支护体系在软岩大变形公路隧道中的应用研究

发布时间：2018-11-20 06:23

【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。
[Abstract]:Along with the cracking of lining, the distortion of steel support and the breaking of bolt, the traditional strong support system is facing great challenge in the treatment of large deformation tunnel. Based on the idea that the deformation of surrounding rock can be reasonably released and the stress of supporting structure can be optimized, a new design concept of time-strong pressure support is put forward. According to the design concept, a pressure-transfer support system is proposed based on the shrunken steel arch frame with deformable groove or pressure-transfer controller. On the basis of this support system, combined with the large deformation characteristics of Dujiashan highway tunnel, the key technical problems of the system, such as the initial pressure point and the pressure yield, are studied. The results show that: when the supporting system is adopted, The later the initial pressure point is or the greater the pressure is, the more the strain energy of surrounding rock is released, and the smaller the load of supporting structure is. However, if the pressure is small or the initial pressure point is too early, the purpose of effectively releasing the deformation energy of surrounding rock and improving the stress of supporting structure can not be achieved. If the initial pressure point is too late or the pressure is large, the displacement of the surrounding rock can be fully released, but it may lead to the destruction of the surrounding rock or even the risk of collapse because of the excessive amount of release. Therefore, the setting of the initial pressure point and the pressure yield in the supporting system should be reasonably selected in combination with the concrete project.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;杭州丰强土建工程研究院;浙江省交通规划设计研究院;
【基金】：国家自然科学基金资助项目(51378434,51578456);国家自然科学基金高铁联合基金资助项目(U1134208)
【分类号】：U455.7

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