带撑式基坑支护结构变形影响因素分析

利用有限元分析软件ANSYS对一典型带撑式基坑工程在开挖过程中的变形进行模拟分析,将模拟计算结果与实测值进行比较,验证该方法的可行性。并进一步对影响基坑变形的几个主要因素：支护结构的墙体刚度、墙体入土深度、支撑刚度、支撑位置、基坑平面尺寸效应及基坑底面以下土体强度等进行系统分析,提出带撑式基坑开挖变形控制的支护设计概念和建议。

ANALYSIS OF FACTORS AFFECTING SUPPORT STRUCTURE DEFORMATION OF FOUNDATION PIT WITH BRACE

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.