Soil and water characteristics analysis based on adsorption-capillary coupling

Unsaturated soils are widely distributed in Northwest China, and their mechanical properties are synergistically influenced by adsorption, capillarity, and solute effects, which are crucial to engineering safety. To address the limitation of traditional models featuring single-mechanism analysis, this study integrates Lu's adsorption model (2019) and the Young-Laplace equation to establish a multi-mechanism coupled analysis framework. The fractal dimension of soil pores was determined, and the soil-water characteristic curve (SWCC) was tested across the full suction range of 0-400,000 kPa. The model demonstrates high fitting accuracy, which can precisely reflect the relationship between water content and suction of unsaturated soils as well as the regulatory mechanism of permeability.