Soil Water Characteristic Curve Analysis of Weathered Granite Soils with Various Fine Content

Determining the parameters related to unsaturated soil properties considering capillary and adsorption phenomena is challenging. In addition, the matric suction generated in unsaturated soil increases the stability of the slope; however, the decrease in matric suction owing to heavy rain causes a decrease in slope stability. Therefore, it is crucial to determine the parameters of unsaturated soil accurately. In this study, the engineering characteristics in the unsaturated state were analyzed using weathered granite soil, which is typically distributed in mountainous areas in Korea. Four samples were prepared in which the compositions of the fine contents of weathered granite soil were 0%, 10%, 20%, and 30%, and a soil characteristic curve test was performed on the samples. In the coefficient prediction method, the widely applied van Genuchten model was used to analyze the air entry value and parameter values according to the fine content of weathered granite soil in the range of the drying process. As a result, a correlation between the fine content in the weathered granite soil and the air entrainment value and parameter values was identified.