大连地铁兴工街站复合地层超大跨浅埋暗挖施工关键技术

大连地铁一期工程203标段兴工街站开挖断面为343.8 m2，洞顶埋深7.1~11.1 m，采用暗挖顺作法施工。为有效控制地表、地下管线及周边建筑物等变形或沉降，同时确保支护结构受力稳定，防止掌子面及隧道坍塌，采取在车站拱部全长范围设置超前大管棚+小导管，增加二次初期支护及纵梁，加强拱部支护结构刚度，形成拱盖，设置边墙锚索维护直墙稳定，并按照双侧壁导坑法分6部组织拱部开挖、台阶法分层分块组织中下部开挖，特别是中下部开挖采取竖向松动爆破拉中槽、边墙光面爆破跟进支护的方式，减小了对拱部支护体系稳定性的影响，全面确保了施工安全。

Key Construction Technologies for Mined Metro Station Tunnels with Super-large Span and Shallow Cover Located in Complex Ground:Case Study on Xinggong Street Station of Dalian Metro

Xinggong Street station of 203 bid section of the 1st phase of Dalian Metro is constructed by bottom up mining method. The excavation cross section area of the station tunnel is 343.8 m2 and the thickness of the cover of the station tunnel ranges from 7.1 m to 11.1 m. During the construction of the station tunnel, technologies, including installing advance large pipe roof + small duct at the arch of the station tunnel, adding the second layer of the primarysupport and longitudinal beam, improving the rigidity of the arch support structure, using side wall anchor to protect the stability of the straight walls, adopting six step double side drift method for top heading excavation, adopting bench cut method, adopting vertical loosening blasting method and smooth blasting method for the central and lower part excavation, are used, so as to control the settlement and deformation of the ground surface, the underground pipe lines and the surrounding buildings, to guarantee the stability of the support structure and to prevent collapse of the working face and the tunnel. In the end, the influence on the stability of the support system of the arch is reduced, and the construction safety is guaranteed.