深基坑降水与地面沉降变形三维全耦合模型及其数值模拟

针对第四纪松散沉积层地区深基坑降水引起的地面沉降问题，以比奥固结理论为基础，并将其推广应用于非线性问题。考虑到土的渗透性随应力状态的动态变化，将地下水渗流场和土体应力场相耦合，建立水土全耦合模型，并以上海市环球金融中心深基坑降水为例，采用三维有限元数值分析方法，详细模拟分析了降水引起的基坑内外地下水位和地面沉降变形的变化特征，据此获得的基坑中心水位降至-22m时基坑周围的地下水位与地面沉降变形量，经后续工程验证正确、可靠，该模型具有重要的工程实用价值。

Numerical simulation based on the three dimensional full coupling model between deep foundation pit dewatering and land-subsidence

To calculate the land subsidence caused by deep foundation pits dewatering in quaternary loose sediment layer,a mathematics model based on Biot's consolidation theory was built.Then Biot's consolidation theory was extended and applied to non-linear question.A 3D coupling-model of seepage and stress was established with considering the dynamic change of permeability coefficient by the different stress state.The three dimension finite element analysis method was used in Shanghai Huanqiu Finance Center foundation pit dewatering,to simulate and analyze the character of groundwater level and land subsidence distortion around the foundation pit by dewatering in detail,accordingly the groundwater level and the land subsidence distortion quantity around the foundation pit are achieved as the water table of the foundation pit center reduces to-22m,which was proved to be correct and reliable by follow-up project.The model has important significance in project practice.