粘弹塑本构模型及用于冻土数值计算的柔度矩阵

随着寒区经济发展及冻结法施工技术在工程中的推广应用,对冻土蠕变的深入研究显得尤为重要.对冻土单轴流变试验结果分析,用非线性牛顿体替代线性牛顿体,从而对西原模型进行了改进,得到了冻土三向应力状态下的本构方程;并利用D-P屈服准则推导出应用与数值计算的柔度矩阵.通过有限元程序的二次开发,将本构模型添加到大型非线性程序ADINA中.用三轴蠕变试验检验了粘弹塑本构模型,获得相应的试验拟合曲线.结果表明:三轴蠕变试验与理论计算结果吻合良好,说明粘弹塑本构模型可以描述冻土在高应力下反映的非衰减性蠕变变形特征.

Viscoelastic Plastic Model of Frozen Soil and Numerical Calculation Soft Matrix Applied

With the development of industry and agriculture in cold regions and spread of the construction technology of artificial freezing,study on the rheology of frozen soil becomes very important.In this paper,Lots of frozen clay specimens are used for the long-term creep tests under single-axial stress states.In order to replace the linear Newtonian body with non-linear Newtonian body,Nishihara Model must be improved.The improved Nishihara Model is proposed to describe the triaxial nonlinear creep constitutive function.Adopting Drucker-Prager(DP) yield model,a soft matrix is derived for numerically calculating.The improved Nishihara Model is added to ADINA FEM,through a secondary developing of finite element program.The improved Nishihara Model is verified by triaxial experiment.The final fitting curves and the theory calculation indicate that the calculated results coincide with the experimental ones very well.The model is able to describe the features of non-linear accelerative creep of frozen soil.