A unified constitutive model for dual-yield surface for warm frozen soil and its verification

The constitutive model for warm frozen soil is crucial for accurately calculating the stress and deformation of frozen soil layers. Based on the modified Cambridge model and the dual-yield surface theory, taking into account the influences of cohesion and internal friction angle of warm frozen soil, the deformation characteristics of the specimens are described by the overall deformation curve ε_v-lnp. The hardening parameters of the current yield surface and reference yield surface are modified by stress path correlation factors. A unified constitutive model of dual-yield surface for warm frozen soil is proposed. The incremental form of the stress-strain relationship is obtained based on the elastic-plastic theory. A convenient method for determining the model parameters is provided. The consolidation parameters and potential strength parameters that reflect the current state of warm frozen soil are defined. An analysis of the dynamic cyclic relationship and interdependence between these parameters and hardening parameters is presented. The experimental data are used to validate the constructed constitutive model, and the results show that the proposed model can accurately predict the stress-strain behavior of warm frozen soil under conventional triaxial stress conditions.