Study On The Deformation Law Of Retaining Structure In Subway Station Foundation-Pit In Loess Area With Monitoring And Numerical Simulation

The study of design and stability analysis of retaining structure in subway station deep foundation-pit in loess area is one of the key subjects of construction of subway station in loess area.The study of deformation law of retaining structure in urban subway station foundation-pit in loess area has important value. This article is based on some urban subway station foundation-pit project, use the manner of combine assume study of theory, deformation law of retaining structure in urban subway station foundation-pit is studied by in-situ monitoring and FEM simulation. The main jobs are as follows:(1)The deformation mechanics and destroy pattern of deep foundation-pit is studied; the main impact factor of deep foundation-pit stabilization is analysised. When the excavation begins, the deformation and earth pressure of the retaining structure in the foundation-pit will change accompany to the time and space's changes. It is to say that the process of the foundation pit excavation existences time and three-dimensional effect. The result indicates that: the main impact factors of retaining structure of retaining structure are earth press hydrographic geology condition, poling condition, retaining structure stiffness, strength of soil horizon, ground water condition and so on.(2)The design of monitor scheme and retaining structure in foundation-pit scheme is completed,in-situ monitoring of deformation law of retaining structure in deep foundation-pit is preceded.The deformation law of retaining structure construct process is emphasis analysised,alteration law of the veritical deformation of ground surface soil body follow the depth and time of deep foundation-pit excavation .the result indicates that the steel shotcrete and retaining structure have limite action to soil body lateral deformation.In the process of excavation of the foundation-pit, the horizontal displacement of fender post and vertical displacement of ground surface are all less than design value, it illustracts that the design scheme is comparatively conservatism, but it's safe to the engineering.(3)Elasto-plasticity finite element analysis method is given to model to simulate construction process for subway station deep foundation-pit excavation.Compare the calculation result to practice monitor result of retaining structure horizon deformation and vertical deformation of ground surface soil body, they are anastomotic, the result counted by FEM is credibility.(4) The FEM simulation is used to study the law of the effect of urban subway station deep foundation-pit stabilition in loess area by changing of the foundation-pit fender post depth in the soil, the position of the steel shotcrete and soil body mechanics character of loess .