The freeze-thaw is an important research subject in frozen soil mechanics and engineering. Due to the effect of temperature periodic fluctuation, the land surface in cold regions will freeze and melt repeatedly, which will change the structure of soil and induce changes of physical and mechanical property of soil. These important factors are considered in the engineering construction of cold regions. 

The scientific research personnel from CAREERI used the silty clay from the Tibetan Plateau as the research object for evaluating the structural change induced by freeze-thaw. The electrical resistivity of saturated remolded soil was measured for analysis of change before and after freeze-thaw was carried out for quantitative analysis of the changes in bonding between particles. The strength parameters obtained by unconsolidated undrained triaxial (UU) tests were correlated with the resistivity and CT damage. It is found that the resistivity of soil increases after freeze-thaw due to the changes in pore distribution, which increase internal friction angle of soil. In the meantime, it is revealed that freeze-thaw leads to increase CT number and negative CT damage for all specimens. Correspondingly, the cohesion of specimens increases after freeze-thaw due to enhancement of bonding among soil particles. The variations of strength parameters are therefore closely related to the changes in bonding, redistribution of soil particles and the distribution ratio of porosity subjected to freeze-thaw.