# Effects of Cyclical Climate Change on Water Temperature Characteristics of Permafrost Slopes
## 3 Results and Discussion
### Freeze-Thaw Water Temperature Characteristics
(**a**) Initial freezing stage; (**b**) freeze stabilization stage; (**c**) thawing stage. Figure 9: Depth of central freeze–thaw front. layers. However, the deep layers warm more slowly, resulting in a gradual decrease in temperature with depth. Figure 11 shows the variation in moisture content with depth at different freeze-thaw stages of the slope. In the early freezing stage, the surface layer experiences a sharp decrease in moisture content due to the freezing and migration of water caused by low temperatures. The middle layer shows a smaller change with a reduced gradient, as the temperature effects are delayed. The deep layer remains relatively unchanged due to slower heat transfer and good thermal insulation. During the stable freezing stage, the surface layer undergoes minimal changes as most of the moisture freezes or reaches a stable mixed state. The middle layer stabilizes after adjustment, with little fluctuation in temperature. The deep layer remains unaffected by external influences and maintains its original state. In the thawing stage, the surface layer experiences a sharp increase in moisture content due to the melting of ice and gravity-driven infiltration [3]. The middle layer shows delayed changes with smaller amplitudes, as heat transfer is slower and the amount of ice is lower. The deep layer experiences the smallest changes due to slower heat transfer and gradual warming. The variation in maximum ice content and its corresponding temperature during the freeze-thaw process of frozen soil slopes is illustrated in Figure 12. From the figure, it is evident that during the freezing stage, as the temperature decreases, water gradually transitions from liquid to solid, forming ice crystals, which leads to an increase in the ice content of the soil. The advancement of the freezing front is accompanied by the accumulation of ice, causing the ice content in the frozen region to continue rising. Simultaneously, the volume expansion of ice induces frost heaving, which leads to the migration of pore water toward the freezing front or infiltration into the unfrozen areas. In contrast, the thawing stage exhibits an opposite trend: as the temperature increases, the ice begins to melt, and the ice content gradually decreases. The meltwater redistributes and infiltrates into other parts of the soil, with the ice content significantly reduced toward the end of the thawing process, approaching zero or the minimum value, indicating that the ice has fully melted, leaving only liquid water distributed within the pores. The bar chart further quantitatively analyzes the variation in maximum ice content, with the freezing stage showing a significant accumulation of ice, while the thawing stage shows a gradual loss of ice. This process may be accompanied by soil subsidence, leading to a significant reduction in soil strength. Overall, Figure 12 reveals the complex coupling relationship between temperature variations, latent heat release during phase changes, heat transfer, and the dynamic distribution of ice content during the freezing and thawing processes. Figure 11: Variation in moisture content with depth at different freeze–thaw stages of slope. (**a**) Initial freezing stage; (**b**) freeze stabilization stage; (**c**) thawing stage.