Study on the influence of dry-wet cycles and salinity on the permeability characteristics of saline loess

Soil salinization is a significant challenge to land use in NW China, and the continuous dry and wet cycles in the region also have long-term effects on the engineering properties of saline soils. In this study, dry and wet cycles tests were conducted on artificially prepared salinized loess to analyze the hydraulic properties of saline soils under alternating dry and wet conditions. The saturated infiltration coefficient and soil–water characteristic curves of the soil specimens were measured after dry and wet cycling. Numerical simulation models were employed to quantitatively analyze the effects of dry–wet cycles and salt content on soil permeability properties. The study found that salt content had a significant effect on the saturated permeability coefficient of saline loess, and that the permeability coefficient of the soil decreased and eventually stabilized with an increase in the number of dry and wet cycles. The experimental results were used to establish a saturated permeability coefficient model and a soil–water characteristic curve fitting model, which take into account the number of dry and wet cycles and soil salt content effects, and the models were then used to predict and analyze the unsaturated permeability coefficient of the soil.