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.