ABSTRACT
In the cold zone of the Qinghai-Tibet Plateau, the coupled effect of freeze-thaw fluctuations and dynamic loads is pivotal in the dynamic response and meso-structure of subgrade saline soil. The dynamic triaxial test and CT scanning were performed to study the dynamic cumulative strain development and damage evolution of freeze-thawed gravelly saline soil (GSS). The results reveal that the cumulative dynamic deformation of GSS is susceptible to the freeze-thaw process, which grows markedly with the rise of freeze-thaw cycles. As the dynamic loading cycle count grows, the cumulative dynamic strain shows a three-stage feature expressing a logarithmic-linear relationship with several loading cycles at different stages. The soil structure tends to be loose, resulting from the freeze-thaw episodes and the remarkable rise in macropore amounts. Due to the combined impact of freeze-thaw episodes and dynamic stress on the soil framework, the CT value in the scanning layer will change in the final state.
