Elasto-plastic behaviour of frozen soil subjected to long-term low-level repeated loading, Part II: Constitutive modelling

- Empirical functions on the long-term elasto-plastic behaviour are presented.
- A constitutive model is produced by empirical functions and elasto-plastic theory.
- A numerical scheme is developed to apply the constitutive model framed in FEM.
- The model is verified for frozen soil with the aid of the triaxial test results.
- The excellent performance and existing shortcomings of this model is discussed.

Based on the conclusions from the experimental investigation in Part I, empirical equations for the accumulated shear strain, accumulated direction ratio and elastic modulus of frozen soil are derived. The basic issues observed in the test results can also be observed in these empirical equations. Subsequently, an elaborate constitutive model for frozen soil subjected to long-term low-level repeated loading is produced by combining the empirical equations and classical elasto-plastic theory. This model accounts for the dependency of the accumulated behaviour on the initial stress state, repeated stress amplitude and frozen soil strength. In addition, the evolution behaviour of the elastic modulus with accumulated strain is also considered. The model is verified for frozen soil with the aid of the triaxial test results represented in Part I. This study is the first attempt to model the elasto-plastic behaviour under long-term low-level repeated loading for frozen soil.