Abstract:Based on the elastoplastic theory,the three-dimensional finite element method is used to simulate the support structure deformation of a typical foundation pit with brace in the process of practical excavation with ANSYS. Comparing the simulated results with the test data,satisfactory results are obtained. A systematic analysis is done to research the influences of the several main factors on the support structure deformation of foundation pit,including support structure rigidity,support structure depth under the bottom of foundation pit,brace rigidity,brace position,foundation pit geometrical dimension and soil strength under the excavation face. The results indicate that the support structure rigidity and depth under the bottom of foundation pit have great influences on the displacement of support structure;and the brace position has more influence on the support structure deformation than that of brace rigidity. Besides,the changes of the brace rigidity,brace position and geometrical dimension of foundation pit have much influences on the displacement of support structure above the excavation face;the improvement of soils strength under the excavation face can control the deformation of the support structure effectively;and the influence of the foundation pit space should be considered. Finally the rational conceptions and suggestions on support structure deformation control are proposed to guide the design and construction.