连霍高速杏花村1号大跨扁平超大断面隧道开挖方案研究

为研究大跨扁平超大断面隧道围岩和支护结构受力变形影响，以连霍高速杏花村1号隧道为工程背景，采用有限元软件FLAC3D对V级围岩进行数值模拟，对双侧壁导坑法和三台阶四部开挖法在隧道开挖时的位移、塑性区、初期支护应力的影响规律进行了研究，提出适用于大跨扁平超大断面隧道不同地质条件下安全经济的开挖方法。对比分析结果表明：隧道开挖时，采用三台阶四部开挖法的隧道拱顶位移、临时支护结构的应力、隧道岩体周边位移较采用双侧壁导坑法大。双侧壁导坑法安全性更高，对围岩位移的控制效果更好，为今后此类工程的施工提供经验和理论指导。

Study on The Excavation Scheme of The Large-span Flat and Super-large Section Tunnel of Lianhuo High-speed Xinghua Village No.1

In order to study the effect of force deformation on the surrounding rock and support structure of large-span flat and super-large section tunnel, based on the engineering background of Lianhuo High-speed Xinghua Village No.1 tunnel, numerical simulation of class V surrounding rock was conducted using the finite element software FLAC3D. The influence laws of displacement, plastic zone and initial support stress during tunnel excavation were investigated for the double-side heading method and the three steps and four steps excavation method. A safe and economical excavation method applicable to large-span flat super-large section tunnels under different geological conditions is proposed. The comparative analysis results show that the displacement of the tunnel vault, the stress of the temporary support structure, and the displacement around the tunnel rock are larger for the three steps and four steps excavation method than for the double-side heading method. The double-side heading method is safer and has better control of the surrounding rock displacement. The study is expected to provide experience and theoretical guidance for the construction of such projects in the future.