A novel approach to water-salt migration prevention: foamed lightweight soil barrier layer technology

This study proposes a novel foamed lightweight soil (FLS) barrier layer technology to prevent water and salt migration and address subgrade diseases in seasonally frozen saline soil regions. A series of experiments were conducted to assess the feasibility and effectiveness of this approach. Initially, ten different ratios of FLS were selected, and the corresponding samples were tested for unconfined compressive strength (UCS) and durability characteristics to determine the optimal ratio for the FLS barrier layer. Subsequently, water-salt migration tests were performed under various conditions, including different salt contents and barrier layer positions. The results demonstrated the barrier layer's good performance in preventing salt-induced deformation of saline soil. In the soil with 3 % salt content, the vertical deformation of samples with a barrier layer was only 25.8 % of that observed in samples without the barrier. Further analysis of water-salt migration revealed that the barrier layer effectively prevented migration from the bottom of the sample toward the colder region, mitigating salt swelling caused by accumulation at the top. Scanning electron microscope (SEM) analysis revealed that the porous structure of the FLS can store salts and provide sufficient space for salt swelling.