Investigation on creep behavior of warm frozen silty sand under thermo-mechanical coupling loads

In cold regions, the creep characteristics of warm frozen silty sand have significant effect on the stability of slope and subgrade. To investigate the creep behavior of warm frozen silty sand under thermo-mechanical coupling loads, a series of triaxial creep tests were carried out under different temperatures and stresses. The test results reveal that the creep strains decrease as the consolidation stress increases, and finally tend to be equal under the same loading stress, regardless of whether the stress is isotropic or deviatoric. Additionally, warm frozen silty sand is highly sensitive to temperature, which greatly influences the creep strain both in the consolidation stage and loading stage. Furthermore, based on the creep test phenomena, a new creep model that considers the influence of the stress level, temperature, hardening, and damage effect was established and experimentally validated. Finally, the sensitivity of the model parameters was analyzed, and it was found that the creep curve transitions from the attenuation creep stage to the non-attenuation creep stage as the temperature coefficient and stress coefficient increases. The hardening effect gradually changes to the damage effect as the coupling coefficient of the hardening and damage increases.