基础托换对基坑周边建筑物变形控制作用的三维有限元分析
Three-dimensional finite element analysis of effects of foundation underpinning on deformation control of existing buildings adjacent to a deep excavation
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摘要: 鼎鼎外滩深基坑工程紧邻上海市历史保护建筑,由于基坑挖深很大且建筑物距离基坑很近,采用锚杆静压桩基础托换技术对邻近的浅基础保护建筑进行了加固处理。采用Plaxis3D软件建立基坑及邻近建筑物的三维有限元模型,土体采用HS-small小应变本构模型,对基坑开挖过程进行了模拟。数值分析及与实测数据的对比表明:基于HS-small本构模型的三维有限元分析能较好地模拟基坑的变形和对邻近建筑物的影响,基础托换能够显著减小基坑开挖对周边浅基础建筑物的影响。Abstract: The excavation of Dingding Bund is adjacent to an existing heritage architecture. As the pit is as deep as 20 m and the heritage architecture is only about 3 m away from the excavation, foundation underpinning is adopted in order to minimize the influences of the excavation on the buildings. To investigate the effects of foundation underpinning on the deformation control of the existing buildings, a series of three-dimensional finite element analyses are carried out by using Plaxis 3D. The soils are modeled by using the HS-small model. By comparing the field monitoring and numerical results, it is shown that the three-dimensional finite element analyses based on the HS-small model can give fairly reasonable predictions of the excavation deformations and the settlements of the adjacent building. The foundation underpinning can effectively reduce the settlements of the additional building induced by the adjacent excavation.