中文摘要：

对Q2黄土进行不同含水状态下的三轴蠕变试验，结果表明，随着含水率的增高，Q2黄土的流变性能增强。根据试验曲线形态特征，选用一个广义Kelvin模型串联一个非线性粘塑元件组成非线性粘弹塑性模型（改进的西原模型）。应用改进的西原模型对试验数据进行拟合求参，结果显示瞬时变形模量EH、粘弹性变形模量Ek、粘弹性粘滞系数ηk随含水率增加呈指数形式递减。引入含水损伤变量D（ω），计算得出各蠕变参数含水损伤演化方程，进而建立考虑含水损伤的非线性蠕变模型。应用试验数据对其进行验证，证明考虑含水损伤的非线性蠕变模型能够有效的描述Q2黄土的整体流变特征。

英文摘要：

Triaxial creep experiments were performed on Q2 loess with different moisture contents. The experimental results showed that the rheological properties of Q2 loess strengthen with the increasing of moisture content. According to the experimental curve shape characteristics, the nonlinear viscoelastoplastic model （improved Nishihara model） was constituted by connecting a generalized Kelvin model with a nonlinear viscoplastic body in series. The improved Nishihara model was used to fit the test data and analyze the model parameters, which suggested that instantaneous deformation modulus （EH）, viscoelastic modulus （Ek）, and viscoelastic coefficient of viscosity （ηk） decrease in the exponential form with the increasing of moisture content. The water damage parameter D（ω） was introduced to derive the damage evolution equation of each creep parameter, and the nonlinear viscoelastoplastic model with water damage effect was established. The experimental data were used to verify the model, and the results suggested that the nonlinear creep model considering water damage can characterize the overall rheological properties of Q2 loess effectively.