Study on Excavation Method of Tunnel with Super Cross-Section and Super Large Section Area Underpass Extra-High Building

Because double side drift excavation method named eye excavation method has been a mature and reliable excavation method, it has normally been used in tunnels with super cross-section and super large section area. However, the construction speed using this method is very slow. One of reasons is that the construction technology of this method would be more and complex. The other is that all construction workers, materials, equipment would be extremely difficult for their up and down, and that the ballast rock would have to be moved by artificial when the upper step of the middle guide hole would be excavated. In this paper, to speed up the process of excavating tunnel with super cross-section and super large section area underpass extra-high building, the elastic-plastic numerical simulations for the tunnel named Industry and Trade Station of the third line in Chongqing Rail Transit were made in four excavation methods conditions. The four excavation methods is respectively the double side drift excavation method to the first excavation in main building side, the double side drift excavation method to the first excavation in podium side, the single side drift excavation method in the upper step to the first excavation in main building side and the single side drift excavation method in the upper step to the first excavation in podium side. The main building is named Industry and Trade building with 22 floors. The results showed that the single side drift excavation method in the upper step could Insure the building and tunnel when the support measures were reasonable, that the guide hole beside the little surface load should firstly be excavated by whether double side drift excavation method or single side drift excavation method, and that these would provide a reference for some similar engineering.