通过采样试验获取了三峡工程二期上游围堰堰体结构材料 2 种主要成分的力学特性和基本性质，总结了其变形规律。根据试验成果和实测，提出了既可以描述材料的蠕变过程行为，又能描述材料应力松弛特性而且符合大多数材料的粘弹性力学特性的三参量堰体材料流变本构模型。基于 Duncan E- μ模型，编制了有限元分析程序。根据围堰运行部分实测变形数据，计算了堰体及防渗墙的变形。通过计算可知，在汛期高水头作用下，堰体及防渗墙结构在一次荷载作用下的瞬时变形呈现以下的规律：堰体大部分单元的垂直位移均表现为沉降位移，只有少数单元在高水头作用下出现向上的位移；防渗墙结构变形与堰体结构变形基本协调一致。这说明围堰结构在高水头作用下能够安全运行。

The mechanical properties and features of two main components of the Three Gorges Project's Phase II cofferdam are obtained based on sampling and experiments and the deformation law is found. Based on the experimental results and measurement, the 3 parameters rheological model is put forward, which can describe not only the behavior of creep, but also the feature of stress relaxation and that corresponding with the viscoelasticity of majority materials for the cofferdam material. The model meets the viscoelastic mechanical properties of most materials. Based on the Duncan E- μ constitutive model, the FEM analysis is programmed. According to the measured deformation data of the cofferdam, the deformations of cofferdam and cutoff wall are calculated. The computation result shows that under the high head in flood season and once load, the instantaneous deformation has the following law: the vertical displacement of most cofferdam elements is settlement, only a few are upward displacement. The structural deformation of the cutoff wall is consistent with that of the cofferdam, which proves that the cofferdam can operate safely under high head.