Deformation Characteristics Analyses Of Deep Foundation Pit In Shenyang Metro Station

The Current Situation of the research on the deep foundation pit enclosure structureand its surrounding ground surface deformation characteristics during the constructionof the subway stations in Shenyang is weak and superficial.To enhance the relative research in this area, utilized the existing methods for theresearch of soft soil foundation pit deformation to deeply study the foundation pitdeformation characteristics by theoretical analysis, construction site surveillance andmonitoring and numerical simulation with the engineering support of the deepfoundation pit construction of Xia Shengou subway station in Shenyang.Through the deformation analysis of foundation pits which have the completedeformation surveillance and monitoring information and which are similar to thefoundation pit mentioned at first in supporting structure and geological situation ofengineering, an empirical mathematical formula for determination of the location of themaximum ground surface subsidence and a method to calculate the value of themaximum surface subsidence are proposed. The results from the calculation with theapplication of the formula and method mentioned above in deformation of deepfoundation pit of Xia Shengou subway station show its accuracy and resemblance toreality.The survey data displays that both the deformation of exterior-protected constructionand the ground surface subside of around are well controlled under the shoring by thebored piles and the steel bracing supporting. The deformation of the exterior-protectedconstruction and the ground subside is building-up by the time effort. The pile bodydeformation is not very and randomness in the stage of earthwork. The sidesway fromthe top of pile to about13m deep under the ground is nearly the same and from13mdeep to the end of pile is gradually to0and the maximum vertical deformation of theground is found nearby10m of the foundation pit in the time of finishing excavatingafter45days.The deformation law of the ground surface is well reflected by the the FEM softwareMidas/GTS.The deformation of exterior-protected construction and the ground surfacesubside of around will have different levels effect in the change of the cast-in-place pile spacing and the pile buried depth. Comparatively speaking, a greater impact of thedeformation is made by the improved the cast-in-place pile spacing.