Evolution of multiscale pore structure in saturated silty clay under non-coaxial F-T cycles

This study investigated the critical boundary condition of non-coaxial freezing-thawing (F-T) action, using a custom-built intelligent unidirectional F-T apparatus to conduct unidirectional F-T cyclic experiments under varying F-T and consolidation angles, numbers of F-T cycles, and freezing temperatures. By integrating CT scanning and mercury intrusion porosimetry (MIP), the multiscale pore structure characteristics of saturated silty clay were evaluated. The results indicated that the F-T and consolidation angle significantly influenced the development of soil crack networks and the evolution of pore structure. Meanwhile, moisture migration patterns varied considerably under different freezing temperatures. The proposed multiscale void fractal dimension calculation method enabled a unified quantitative characterization of structural evolution across the entire pore-size spectrum in freeze-thawed soil under complex boundary conditions. These findings provided essential theoretical and experimental support for analyzing and preventing thaw-induced landslide mechanisms in seasonal frozen regions.