Foundation stability evaluation system for transmission towers on silty sand subjected to freeze–thaw cycles

The performance of transmission tower foundations in seasonally frozen regions is strongly influenced by multiple coupled fields. This study developed a numerical model of the interaction between silty sand and the stepped foundation of a transmission tower subjected to freeze–thaw cycles. The model was applied to analyzing soil–foundation interactions considering single and multiple factors including the initial moisture content, groundwater level, and freeze–thaw cycles. The results were used to clarify the macroscopic characteristics and leading causes of instability in seasonally frozen regions. A foundation stability evaluation system was established that integrates variable weights to consider subjective and objective factors and a cloud model to process fuzzy stochastic information. The evaluation system was applied to assessing the stability of the transmission tower, and its assessment was compared against those of experts. This study provides a theoretical basis for preventing and mitigating foundation-related disasters in seasonally frozen regions.