Structural change of soil due to freeze-thaw is the primary cause for the variation of mechanical properties. In this paper, silty clay from the Tibetan Plateau was taken 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 of soil pore properties, while CT scanning of soil 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.

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