Abstract:

The earthen sites in the arid areas of northwest China are widely affected by the salinization of foundation soils. Due to the lack of research on earthen site foundations, this study investigates the salt migration patterns of the foundation and wall roots at the Great Wall site during short-term heavy rainfall and natural drying cycles. Conductivity, moisture content, and other parameters are utilized in laboratory experiments to analyze surface deterioration, with NaCl as the migration salt. It is observed that as the number of rainfall-drying cycles increases, the facades of earthen sites exhibit phenomena such as basal collapsing (erosion), salt efflorescence, epidermal cracking, and hollowing. The phenomena of capillary rise, salt migration, and surface deterioration in earthen sites are interconnected. After several cycles, the salt supply pattern in the foundation was adjusted, the salt migrate at the root of earthen sites is limited in scope. These findings elucidate the salt migration mechanism at the foundation roots and earthen sites during the alternation of rainfall and evaporation. This study offers insights for preventing and protecting against salinity erosion in earthen sites.

Key words: earthen sites, salt expansion, rainfall infiltration, capillary rise, water and salt migration