土石混合体填筑路堤中的非线性蠕变模型探析

Study of nonlinear creep model of earth-rock aggregate embankment

针对土石混合体填筑路堤工后沉降的非线性蠕变特性,提出了一种能考虑材料非线性黏弹性变形的蠕变模型。基于目前对土石混合体蠕变机理研究,将路堤工后的蠕变沉降部分考虑为非线性的衰减蠕变过程,建立了修正的Kelvin模型、广义修正模型,且得到了模型参数的识别方法;通过对修正模型分析表明,非线性常数取值对蠕变曲线变化有较大影响,修正模型的蠕变长期应变值比Kelvin模型要小;结合相关文献中对土石体填料的蠕变试验研究资料,用修正Kelvin模型对试验结果进行拟合,并对参数进行了反演,反演效果良好。修正模型的建立可为编制非线性黏弹性数值计算软件提供理论基础。

According to the nonlinear creep properties of earth-rock aggregate embankment after construction,a modified Kelvin model that can express nonlinear viscoelastic deformation of material is presented.Based on the current research results of the creep mechanism of earth-rock aggregate embankment,the creep settlement after construction is considered to be an attenuation creep process;and the modified Kelvin model,generalized modified model and recognition method of model parameters are presented.Through analyzing the modified Kelvin model,the results show that： the nonlinear constant is an important influencing factor to the model;and long-term strain of the modified Kelvin model is smaller than that of Kelvin model.Based on the creep test data in the related literatures,parameters of modified Kelvin model are fitted;and the fitting effect is well.The modified Kelvin model will distribute theoretical basis for the numerical calculation program of nonlinear viscoelasticity.