In cold regions, the extensive distribution of silt exhibits limited applicability in engineering under freeze–thaw cycles. To address this issue, this study employed rice husk carbon and calcium lignosulfonate to stabilize silt from cold areas. The mechanical properties of the stabilized silt under freeze–thaw conditions were evaluated through unconfined compressive strength tests and triaxial shear tests. Additionally, scanning electron microscopy was utilized to analyze the mechanisms behind the stabilization. Ultimately, a damage model for rice husk carbon–calcium lignosulfonate stabilized silt was constructed based on the Weibull distribution function and Lemaitre’s principle of equivalent strain. The findings indicate that as the content of rice husk carbon and calcium lignosulfonate increases, the rate of improvement in the compressive strength of the stabilized silt progressively accelerates. With an increase in the number of freeze–thaw cycles, the deviatoric stress of the stabilized soil gradually diminishes; the decline in peak deviatoric stress becomes more gradual, while the reduction in cohesion intensifies. The decrease in the angle of internal friction is relatively minor. Microscopic examinations reveal that as the number of freeze–thaw cycles increases, the soil pores tend to enlarge and multiply. The established damage model for stabilized silt under freeze–thaw cycles and applied loads demonstrates a similar pattern between the experimental and theoretical curves under four different confining pressures, reflecting an initial rapid increase followed by a steady trend. Thus, it is evident that the damage model for stabilized silt under freeze–thaw conditions outperforms traditional constitutive models, offering a more accurate depiction of the experimental variations observed.
