Research and Verification of Unified Yield Surface SFG Model considering Temperature Influence

When unsaturated soils are affected by thermal radiation such as sunlight, geothermal heat, nuclear waste, and biochemical reactions, the soil temperature will increase and accelerate soil moisture migration, resulting in soil deformation. Therefore, in this paper, by extending the SFG model of the unified yield surface to consider the effect of temperature change on the unified yield surface, a yield surface constitutive model which can simultaneously reflect temperature-suction-stress is proposed. In order to verify the applicability of the model, the triaxial test of Jiangxi laterite at different temperatures is carried out to determine the calculation parameters of the model, and the fitting results of the model are compared with the experimental results, and the model is fitted and analyzed by referring to the test data of remolded clay used by Uchaipichat. The results show that the model can well reflect the stress-strain characteristics of soil during compression rebound, dehumidification and shear at different temperatures, which provides a theoretical support for predicting and solving the influence of temperature change on the stress deformation and shear strength of unsaturated soil in the corresponding engineering environment in the future, thus further enriching the constitutive theory of unsaturated soil under the influence of temperature.