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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黏塑元件组成非线性黏弹塑性模型(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、黏弹性变形模量EK、黏弹性黏滞系数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。
Triaxial creep tests of Q2 loess at different water contents show that the rheological properties of Q2 loess are enhanced with the increase of water cut. According to the morphological characteristics of the test curve, a nonlinear viscoelastic-plastic model (modified Nishihara model) is constructed by using a generalized Kelvin model in series with a non-linear visco-plastic element. The experimental data were fitted by using the improved Nishihara model. The results show that the EH, EK and viscoelastic coefficient of viscosity ηK decrease exponentially with the increase of water content. The water damage variable D (ω) is introduced to calculate the water damage evolution equation of each creep parameter, and then a nonlinear creep model considering water damage is established. The experimental data are used to verify the nonlinear creep model considering water damage, which can effectively describe the overall rheological characteristics of Q2 loess.