Research on the deformation law of deep excavation supporting structure in metro station of Xi'an by FLAC simulation

The study on the theory of deformation laws and monitoring of deep excavation in metro station in Xi'an has great significance to guide informational construction in deep excavation in northwest.Taking the deep excavation of a metro station of Xi'an subway 2 line as the engineering background in this paper,the design of the monitoring plan on deformation of deep excavation of a metro station was completed,the simulation calculation on construction process of deep excavation was given by FLAC,and the pile deformation,the axial force of steel support and ground settlement around foundation were mainly studied.The results showed that when open excavation construction was carried out in deep excavation of city subway transfer station under complex environment,in-situ monitoring was a useful measure for safety guarantee to information construction.It was rational that compound maintenance program including bored pile and steel support should be adopted to be as supporting structure of deep excavation of metro station.Stratified excavation method of earthwork and applying prestress to steel support were the important measures of reducing spatial effect and guarantee safe construction.The horizontal displacement of pile body,especially pile top was a direct reflection of deformation of the retaining structure,the maximum deformation of supporting pile was from the middle to two-thirds of foundation depth.The ground heave around supporting structure of foundation was much less than the middle of foundation,and as the excavation depth was increasing,the amount of heave in the central part gradually shift from the pit on both sides of a large middle small type.