盾构法与浅埋暗挖法结合建造地铁车站站厅隧道二衬施作时机的研究

摘要

采用盾构法与浅埋暗挖法结合建造地铁车站时,站厅隧道二衬施作时机有横通道开挖之前和之后2种方案.以北京地铁10号线三元桥站为例,采用FLAC3D有限差分软件,对2种方案进行三维数值模拟,从地表沉降和隧道结构内力两方面进行对比分析.结果表明:在6个施工阶段,方案1的最大地表沉降均比方案2的显著减小,方案1的最终地表沉降为48 mm,仅为方案2的最终地表沉降(166 mm)的29％,而且站厅隧道初支内力和需要的配筋量均小于方案2.因此,在车站施工过程中,站厅隧道二衬应在横通道开挖之前施作.%There are two options for selecting the proper construction time of secondary lining in station hall tunnel during the construction of metro station by shield method combined with shallow-buried tunneling method, I. E. Before/after the completion of connecting passage. These two schemes were simulated by three-dimensional numerical method using FLAC3D for the Sanyuan Bridge metro station of Line 10 in Beijing, ground surface settlement and structural internal force in the two schemes were compared and analyzed. The results indicate that> during six construction stages, the final ground surface settlement is 48 mm in option 1, which is only 29% of the total settlement in option 2 (166 mm), so it is concluded that the ground surface settlement can be greatly reduced if option 1 is applied. Moreover, the structural internal force of the initial support in the station hall tunnel and the required reinforcement of option 1 are less than that of option 2. Therefore, the connecting passage should be completed before installing secondary lining in station hall tunnel during the construction of metro statioa