A Review on the Impact of Saline Soil Environments on Thermal Insulation Layers in Cold-Region Tunnels in China

Penglong Wang

doi:10.54097/5hnt6s70

Authors

Penglong Wang

DOI:

https://doi.org/10.54097/5hnt6s70

Keywords:

Cold-region Tunnels, Saline Soils, Thermal Insulation Layers, Frost Damage, Seepage Water Salinity

Abstract

With the advancement of the "Belt and Road" Initiative and the Western Development Strategy, the demand for tunnel construction in cold, high-altitude, and high-latitude regions of China has increased significantly. Frost damage poses a serious threat to tunnel structural safety in these areas, where installing thermal insulation layers is a key measure for prevention. Organic insulation materials such as polyurethane (PU) and expanded polystyrene (EPS) are widely used due to their excellent performance. This paper systematically reviews research progress on temperature field theory, experimental studies, and numerical simulations related to cold-region tunnels, with a focus on the impact mechanisms of saline soil environments on insulation layer performance. Studies indicate a significant positive correlation between Cl⁻ and Na⁺ content in seasonal frozen soil within western China, and water seepage containing salts affects the thermal conductivity of insulation materials by altering their pore structure and moisture content. These effects vary spatially due to regional differences in salinity. While new approaches such as machine learning are increasingly applied to predict material performance and optimize design, systematic research on the long-term impact of seepage water salinity on insulation layers remains limited, representing an important direction for future studies.

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