不同围岩情况下特大断面公路隧道施工变形监测与控制

 以目前国内规模最大的广州龙头山隧道为背景，详细介绍特大断面公路隧道施工过程中变形现场监测的项目、方法及手段，对洞口边坡及不同围岩情况下的隧道变形规律进行分析，并提出控制大变形的工程措施。研究结果表明：(1) 右导洞上台阶、左导洞下台阶和核心土上台阶开挖引起围岩较大变形，是隧道施工主要控制点；(2) 特大断面隧道围岩变形与洞周半径近似成指数函数关系；(3) 封闭支护结构及对拉锚杆的使用是改善结构受力和抑制隧道变形的有效途径，应尽早施作仰拱以形成封闭环。研究成果可为日后类似工程的设计、施工和研究提供有益的借鉴和参考。

DEFORMATION MONITORING AND CONTROL OF SUPER LARGE SECTION HIGHWAY TUNNEL WITH DIFFERENT SURROUNDING ROCKS

Based on Longtoushan tunnel which is the largest in China at present in Guangzhou,the contents,technique and method of deformation monitoring of super large section tunnel are descried. The deformation law of the slope,surrounding rock and support system with different surrounding rocks are analyzed;and the engineering measures to control the deformation are put forward. The result shows that:(1) the construction of the up-stage in the right hole,the down-stage in the left hole and the up-stage of the core soil,which cause large rock deformation,are the main points for controlling the rock deformation;(2) the deformation has a exponential relationship with the radius of tunnel;and (3) the enclose of lining and using of cross anchor is effective method to improve the performance of lining and to restrain the deformation of the tunnel;and it is important to construct the inverted arch and close the lining. The study results can be for reference in the design,construction and research of similar tunnels.