Inner Support Mechanical Parameters Study of Open-cut Subway Station Supporting Structure

Through the combined monitoring and analysis of construction site data of a subway station deep foundation pit project in Beijing, the horizontal displacement of the retaining structure in relation to the depth and time of construction was studied. At the same time, a comparative analysis of calculation and monitoring results of the retaining structure was carried out using FLAC^3D finite element simulation. A quantitative analysis on the effects of the steel support under different pre-axial force and stiffness on the horizontal displacement and bending moment of the pile was conducted. The conclusions are as follows;1) pile measured and simulated values of the horizontal displacement curve trend are generally similar, exhibiting bracket shapes big in the middle and small at both ends, with maximum deformation occuring around the mid-depth of the pit at the right side; 2) pre-axial force has significant influence on the displacement of the pile, therefore, the pre-applied force of steel support should be reasonably chosen to limit deformation of retaining structure in the construction of foundation pit; 3) during excavation of deep foundation pit, pile top horizontal displacement can be reduced by increasing the rigidity of the steel support, in cases where requirement for deformation are high.