Study On Optimizing Construction Schemes For Single-arch Railway Tunnel With Exceptionally Large Cross-section

New Beijing-Zhangjiakou Inter-city railway Badaling underground station is built in the badaling scenic spot in the mountain. As the high-speed railway station, this project in the domestic and global are extremely rare. As the station and external connection, the interval tunnel structure of the building also is very important. Due to the lack of high speed railway tunnel as the reference for the similar project, this paper can only rely on relevant similar highway and railway tunnel as reference.Based on the engineering background of New Beijing-Zhangjiakou Inter-city railway Badaling underground station interval tunnel excavation, the problem of buried deep in large-span single arch structure excavation scheme launched research. This paper adopts "Midas" / GTS finite element analysis software to simulate calculation, and draw some basis and the law as reference in construction process. Major work as follows:(1) This thesis summarizes the domestic and foreign similar project summary and some basic large-span tunnel construction methods, for New Beijing-Zhangjiakou Inter-city railway Badaling underground station construction scheme providing reference.(2)For the four kinds of the Deep-buried Single-arch Large-span Metro Tunnel excavation program (one-side wall drift heading method,single-rock pillar method,CRD-4 holes method,CRD-6 holes method) and the numerical simulation,a detailed analysis of surface subsidence,the peripheral displacement of the tunnel,the scope of the plastic zone generated this number of indicators,and get some laws about the excavation process.(3)Contrasting the various indexes of construction scheme proposed, results showed that CRD-4 holes is superior to other construction scheme. It can offer direct guidance to the proposed Badaling interval tunnel and some reference to similar deep buried or large span projects.