Researched On Stability And Supporting Design Of Deep Foundation In Xi'an Metro

Design of the retaining structure and stability analysis of deep excavation in metro station is one of the key issues in metro construction. The study on the theory of deformation laws and monitoring of deep excavation in Xi'an has great significance. In this paper, it uses the method that combines with the theoretical analysis, in-situ monitoring and numerical simulation followed the background of Deep Excavation in DaMing-gong Station of Xi'an Subway Line. The main jobs are as follows:(1) The deform,ation modes of retaining structures to metro deep foundation have three ,which were bow deformation, forward tilting, kick-type deformation and Flat push type deformation. The influencing factors of deformation of deep foundation pit are discussed, and groundwater is one of the most important factors.The design of the deep foundation pit of the new excavation area is given. The results of the water level monitoring show that the design of the precipitation is reasonable and the purpose of the dry construction is reached.(2)The feasibility of the design of the deep foundation pit retaining structure is verified by the software calculation method in the deep foundation pit. The results showed that the design scheme of the retaining structure with the support pile & steel could ensure that the excavation process Safe and stable, the proposed envelope design is feasible.(4) The deformation monitoring scheme of deep foundation pit of DaMing-gong station is given and field monitoring is completed. The results show that the horizontal deformation of the retaining piles is not large and the maximum is 10.23mm. The steel support can limit the horizontal deformation of the pile in the process of large span excavation.(5) By comparing the numerical values and the field monitoring values, it can be seen that the deformation law and deformation trend of the deep foundation pit are basically the same, which indicates that the numerical calculation method is used to verify the feasibility of the design scheme of the deep foundation pit envelope.