Seasonal freezing and thawing significantly influence the migration and distribution of soil hydrothermal salts. Understanding the dynamics of hydrothermal salt forces in canal foundation soils is crucial for effective canal disease control and optimization. However, the impact on rectangular canals remains poorly understood. Therefore, field-scale studies on water-heat-salt-force-displacement monitoring were conducted for the canal. The study analyzed the changes and interaction mechanisms of water-heat-salt-force in the soil beneath the canal, along with the damage mechanisms and preventive measures. The results indicate that the most rapid changes in temperature, moisture, and salt occur in the subsoil on the canal side, with the greatest depth of freezing. Heat transfer efficiency provides an intuitive explanation for the sensitivity of ground temperature at the junction of the canal wall and subsoil to air temperature fluctuations, as well as the minimal moisture migration in this region under the subcooling effect. The temperature-moisture curve suggests that current waterheat-force and water-heat-salt-force models exhibit a delay in accurately predicting water migration within the subsoil. Rectangular canals are more susceptible to damage under peak freezing conditions, requiring a combined approach of freezing restraint and frost-heaving force to mitigate damage. These findings offer valuable insights for canal design, maintenance, and further research.

With the development of the Chinese economy and society, the height and density of urban buildings are increasing, and large underground transportation hubs have been constructed in many places to alleviate the pressure of transportation. Commercial buildings are usually developed above the large underground transportation hubs, so the underground structures may have very shallow depths or no soil cover. The seismic response and damage mechanisms of such underground structures still need to be studied. In this paper, an example of a project in China is taken as an object to analyze the seismic response and damage mechanism of the structure after simplification. The spatial distribution of deformations and internal forces of such structures and the location of the maximum internal forces are obtained, and the effect of the frequency of seismic motions on the structural response is obtained. Finally, an elastoplastic analysis of such structures is carried out to assess the damage location and the damage evolution process.