Degradation in liquefaction resistance: The impact of freeze-thaw on colloidal silica-stabilized sandy soil

This study investigated the liquefaction resistance of colloidal silica (CS)-stabilized sand after freeze-thaw cycles. Specimens were prepared with three CS contents (6 wt%, 8 wt%, and 10 wt%), and freeze-thaw (F-T) cycles of 1, 2, 4, 6, and 10 were used. Then undrained cyclic triaxial tests were performed to analyze the liquefaction resistance. The findings are: (1) F-T cycles significantly reduce the liquefaction resistance, to the extent that initially non-liquefiable specimens can become liquefiable; (2) the higher the CS concentration, the greater the post-freeze-thaw liquefaction resistance; (3) the first F-T cycle causes the sharpest decline in liquefaction resistance, with the damaging effect of freeze-thaw attenuating thereafter; (4) following the analysis of three different pore water pressure (PWP) models, a new model incorporating freeze-thaw damage effect is proposed; (5) SEM analysis reveals that freeze-thaw causes the development and expansion of micro-cracks, leading to the degradation of the bonding network and liquefaction resistance. The results offer a mechanistic understanding of how freeze-thaw cycles degrade liquefaction resistance, contributing to improved ground design for seasonally frozen environments.