Role of the pore-size distribution function on water flow in unsaturated soil

• Main Authors: Zhai, Qian, Rahardjo, Harianto, Satyanaga, Alfrendo, Priono, Dai, Guo-liang
• Other Authors: School of Civil and Environmental Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Civil engineering; Soil-water Characteristic Curve (SWCC); Hydraulic Properties
• Online Access: https://hdl.handle.net/10356/144384
• Institution: Nanyang Technological University

The hydraulic properties of soil (i.e. soil-water characteristic curve (SWCC) and coefficient of permeability) govern the moisture flow in it. Previous research has indicated that the hydraulic properties of soil are dependent on its pore-size distribution. An improved capillary model is now proposed to explain the concept of the pore-size distribution in soil and its relationship to SWCC. A new model, the “valve model”, is also proposed as the explanation for water flow in unsaturated soil. The pore-size distribution function is incorporated in the “valve model” and is used to calculate the relative coefficient of permeability for unsaturated soil. In this paper, the role of the pore-size distribution function in the estimation of SWCC and the permeability function are explained. Equations are proposed for estimating the pore-size distribution function from the experimental data of relative coefficient of permeability. The results from the proposed equations agree with the experimental data from laboratory measurement and published data.