软土地层基坑群周边地表沉降性状研究

Analysis of Characteristics of Ground Surface Settlement Caused by Excavation Group in Soft Soils

在上海软土地区乍浦路天潼路基坑群项目中,采用小应变本构模型,考虑土与结构共同作用的三维有限元方法,模拟基坑群的复杂施工过程,现场实测结果验证有限元分析的合理性。在此基础上研究因基坑群开挖引起地表沉降的空间效应,以及随着各基坑分区开挖地表沉降的渐次发展过程。结果表明,由基坑群开挖引起地表沉降空间效应显著,在各基坑分区叠加影响及基坑分区相互作用下,基坑群周边地表变形性状与软土单坑地表沉降规律明显不同。基坑群开挖过程中,由于各分区间土体宽度不同,地表沉降曲线呈对称的W形、不对称W形、U形、凹槽型、较平坦的凹槽型等复杂变形形态。

In the Zhapu Road,Tiantong Road foundation excavation group project in Shanghai soft soil area,a three⁃dimensional finite element method considering the interaction between soil and structure is proposed by using a small strain constitutive model,the complex construction process of foundation excavation group is simulated,field measurement results verify the rationality of finite element analysis.On this basis,the spatial effect of ground settlement caused by excavation,the gradual development process of ground settlement along with excavation of each foundation excavation area.The results show that,the spatial effect of ground settlement caused by foundation excavation is significant,the surface deformation behavior around the foundation excavation group is obviously different from the surface settlement law for soft soil single excavation,under the influence of superposition and interaction of each excavation area.During the excavation of foundation excavation group,due to the different soil widths between different foundation excavation zones,the surface settlement curve presents a complex deformation pattern,such as symmetrical W⁃shape,asymmetric W⁃shape,U⁃shape,groove type and relatively flat groove type.