Numerical Modeling of Rate-Dependence Behavior of Saturated Frozen Soil

The saturated frozen soil is composed of solid grains, ice and unfrozen water. The mechanical behavior of this engineering material is strongly associated with the amount of ice. Meanwhile, the amount of ice depends on the temperate and pressure and its existence is the main reason that induced the huge difference between the frozen and unfrozen soil. Furthermore, considering that ice is the highly rate-dependent material, the rate-dependency behavior of the frozen soil can be expected. A rate-dependent constitutive model based on the critical state theory is proposed for describing the rate-dependency of frozen soil. Being a variable parameter, the ice content is directly related to the temperature with can be correlated by the unfrozen water content curve. The tension strength and the pseudo-preconsolidation pressure can be expressed by the ice content. Meanwhile, the compression and recompression coefficient are related to the ice content and the values at the unfrozen condition. The rate-dependent behavior is considering by the over stress method. When the temperature is higher than 0°, the ice content will be null. Then, the model will reduce to the conventional elastic-viscoplastic model. The predictive ability of the model is validated by simulating the 3D undrained triaxial compression test.