# Effects of Cyclical Climate Change on Water Temperature Characteristics of Permafrost Slopes
## 4 Conclusions  
This study investigates the thermal and moisture characteristics of frozen soil during freeze-thaw cycles. By combining experimental data and numerical simulations, it reveals the distribution patterns of the temperature field, moisture migration, ice-water phase change mechanisms, and the indirect impact of water temperature changes on slope stability under freeze-thaw conditions. The study finds the following observations:  
1. During the freezing stage, the negative temperature gradient causes the water inside the slope to migrate towards the freezing front, thereby inducing the formation of segregated ice and the occurrence of frost heave. In the thawing stage, the latent heat released by the melting of segregated ice triggers the migration of water inside the slope towards the toe of the slope. Since there is a potential trend of increased water content at the toe of the slope during both the frost heave and thawing stages, this indirectly increases the risk of slope toe collapse and instability.
2. Under the action of freeze-thaw cycles, the variation in temperature with depth inside the slope can be divided into three stages, namely the initial freezing stage, the stable freezing stage, and the thawing stage.
3. In the initial freezing stage, the water content of the slope soil from \(-3\) m to \(-1\) m is relatively stable, and the number of freeze-thaw cycles has no significant impact on it. The difference in water content of the slope soil from \(-1\) m to \(1\) m gradually becomes apparent. When entering the stable freezing stage, the soil from \(-3\) m to \(-2\) m is in a relatively stable frozen state, and the number of freeze-thaw cycles has a relatively limited impact on its water content. However, the water content of the soil at a depth of \(-2\) m to \(0\) m is redistributed. In the thawing stage, for the soil at a depth of \(-3\) m to \(0\) m, the greater the number of freeze-thaw cycles, the larger the difference in water content.
4. The distribution of heat and water transfer inside the frozen soil slope with depth exhibits non-linear and dynamic characteristics. At the same time, there are differences between frozen soil slopes and frozen soil subgrades. Frozen soil slopes are characterized by one-way freezing, two-way thawing, and a thawing rate higher than the freezing rate. This is the key to understanding the mechanism of slope instability.  
Figure 12: Variation in ice content and temperature in slope.  
The model proposed in this study provides a new framework for analyzing deeply-related hydrothermal coupling. The proposed framework outperforms existing unidirectional models by resolving latent heat effects and bidirectional thawing, offering a robust tool for slope risk assessment. However, its applicability is limited by the assumption of simplified soil homogeneity. Future work should incorporate particle heterogeneity and the effects of organic matter to improve the prediction accuracy of natural slopes.  
Conceptualization, F.D. and B.T.; Methodology, L.Q.; Software, L.Q. and H.W.; Validation, L.Q.; Formal analysis, F.D. and B.T.; Investigation, F.D. and H.W.; Resources, F.D.; Data curation, H.W.; Writing--original draft, F.D. and B.T.; Writing--review & editing, F.D., L.Q., H.W. and B.T.; Supervision, B.T. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
This work was supported by College of Civil Engineering of Chongqing Jiaotong University The authors express their sincere gratitude for the experimental platform provided.  
The authors declare no conflict of interest.