循环荷载作用下粉细砂累积变形的等效粘塑性本构模型

为了提出理论基础明确、计算方法简单有效的适用于长期交通荷载作用下粉细砂累积变形计算的本构模型及数值模拟方法，基于经典弹塑性理论框架，依据安定性基本理论，考虑砂性土材料的双屈服面及剪胀性特征，并引入Suiker（2002）模型中的塑性应变增量表达式，针对无粘性路基材料提出了预测长期累积不均匀变形的等效粘塑性本构模型。数值模拟结果表明，模型对于粉细砂长期循环累积塑性变形具有很好的模拟能力，而且计算步长可相当大，适于大数目循环加载的有限元计算。

An Equivalent Viscoplastic Model for Cumulative Deformation of Silty Sands under Long-term Cyclic Loading

In order to simulate the cumulative deformation of silty sand under long-term repeated loading efficiently and accurately, a new type of constitutive models with strong theoretical basis and high computational efficiency should be considered. An equivalent viscoplastic model basing on shakedown theory is proposed by adopting equations of double yielding surfaces and dilatancy. Moreover, the equation of plastic strain increment proposed by Suiker (2002) is also introduced into the model. By comparison with laboratory test results, it demonstrates that the proposed model is capable of predicting the long-term cumulative deformation successfully and efficiently. Since the step-by-step calculation is avoided, the proposed viscoplasticity framework will be used in the realistic boundary value problems under large cycle numbers.