Work

Effect of soil volume changes on the volumetric water content and saturation degree of the soil-water characteristic curve

Year: 2026

Type: article

Abstract: The amount of water in terms of volume is directly represented by volumetric water content which is crucial for understanding the flow of water through the soil. As the soil suction increases and the water content decreases, volume changes potentially occur in the soil, especially in plastic soil. However, accurately measuring the total volume of soil samples is challenging. Accurate volume change measurement can be done using the three-dimensional (3D) scanner. The objective of this study is to combine an osmotic tensiometer and a 3D scanner to obtain an accurate volumetric water content and degree of saturation-based soil-water characteristic curve (SWCC). A comparison that was carried out between SWCC with and without considering the shrinkage curve (under constant-volume assumption) highlights significant differences. When the shrinkage curve is ignored, the volumetric water content is underestimated as soil volume changes are neglected. Ignoring the shrinkage curve also resulted in lower air entry values compared to those with the shrinkage curve. Including the shrinkage curve in SWCC analysis provides a more accurate representation of unsaturated soil behaviour by accounting for both water content and volume changes, resulting in better predictions of engineering properties such as shear strength and hydraulic conductivity , especially in high plasticity soils such as silt or clay.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2026.110112