中文摘要：

根据沥青混合料3阶段的蠕变特性和混合料全过程应力-应变曲线，对Burgers模型中的粘弹性弹簧进行改进，认为其弹性模量随应变增大而减小；推导了非线性蠕变模型的本构方程，给出了蠕变应变、蠕变速度和蠕变加速度的解析表达式；进行了模型稳定性分析，给出了模型稳定条件和蠕变破坏时间的定义；运用最小二乘法原理，建立了模型参数的确定方法；最后通过两个实例验证了模型的准确性和适用性。研究结果表明，非线性蠕变模型较好地反映了沥青混合料3阶段的蠕变过程，蠕变破坏时间也可作为研究沥青混合料蠕变性能的一个新指标。

英文摘要：

Based on the three-phase creep character and the complete stress-strain curve of asphalt mixture, the viscoelastic spring of Burgers model was modified and a nonlinear creep model was established, in which the viscoelastic spring module gradually decreased when the strain increased. Then, the constitutive relationship of nonlinear model was deduced, and the expressions of creep strain, creep rate and creep acceleration were also given. Meantime, the model stability condition and creep rupture time was defined by analyzing the stability of the nonlinear model, and the parameter determination method was established by the principle of least square. Finally, the proposed model was verified through two experimental examples. It is indicated that the nonlinear model can clearly describe the three-phase creep, especially the accelerating creep stage, and the creep rupture time can also be used as a new index to research the creep character of asphalt mixture. 2 tabs, 5 figs, 10 refs.