A review of the synergistic effects and feedback mechanisms of freeze-thaw on soil sites under vegetation cover

Earthen heritage sites are vital components of cultural heritage with irreplaceable historical and cultural value. Most earthen heritage sites are located in regions with seasonal freezing. Therefore, addressing freeze-thaw damage is essential. Freeze-thaw damage to earthen sites is primarily driven by moisture migration, ice lens formation, and the coupled effects of salt, heat, and stress. Compared to bare soil, vegetation cover has different effects on earthen sites. Positively, root systems enhance soil mechanical stability. Plant canopies reduce erosion and buffer temperature and humidity fluctuations. Negatively, strong transpiration intensifies the formation of desiccation cracks. The physicochemical actions of roots accelerate structural deterioration. The coupling mechanism between vegetation and freeze-thaw cycles is complex. The overall impact varies significantly depending on the plant species and regional environment. Current research faces several challenges, including insufficient long-term monitoring data and a lack of models that integrate multiple physical fields. Future work should focus on several key areas: establishing a threshold system for vegetation-freeze-thaw damage is needed, and developing intelligent predictive models is crucial. The ultimate goal is to enable scientific monitoring and protection through interdisciplinary approaches.