依托重庆轨道交通某软岩地铁车站扩大拱脚初支拱盖法施工过程，对围岩位移、应力及初期支护结构的受力特征进行了分析。扩大拱脚的开挖对拱脚和拱顶的围岩变形都有较大的影响，车站隧道直墙中部、隧道直墙与隧低交接处、扩大拱脚处和拱顶都是比较薄弱的部位，设计和施工过程中应加强支护。研究成果为软岩地铁车站扩大拱脚初支拱盖法信息化设计、施工提供了依据。
Relying on the construction process of initial arch-cover method of expanding arch in a metro station in soft rock stratum of Chongqing Rail Transit, the displacement and the stress of the surrounding rock, and the mechanics characteristics of the initial supporting structure were analyzed. The excavation of the expanded arch has a great influence on the deformation of the arch and the vault of the surrounding rock. The middle of the straight wall of the station tunnel, the intersection of the tunnel’s straight wall and the bottom of the tunnel, the expanded arch and the vault are relatively weak. Therefore, the support should be strengthened during the design and construction. The research results provide a basis for the informatization design and construction using the initial arch-cover method of expanding arch in the metro station in soft rock stratum.
