SWCC Based Prediction Model of Equilibrium Moisture of Clay Subgrade with High Groundwater Table

Abstract

To accurately calibrate the working range of equilibrium moisture of clay subgrade, according to unsaturated soil mechanics basic theories, the filter paper method was used to measure matrix suction and to establish soil-water characteristic curve (SWCC) model with reflecting function between moisture and metrics suction. The prediction method about the working range of equilibrium moisture of unsaturated clay subgrade was proposed and the model was tested. The results show that equilibrium moisture of clay subgrade out the affected range of the precipitation and evaporation is mainly controlled by the impact of groundwater. The Fredlund & Xing model can better characterize the unsaturated cohesive subgrade soil humidity and the correlation matrix suction and the model parameters possessed highly reliability. The prediction result of clay subgrade's equilibrium moisture on groundwater control area has high uniformity with experimental result. The prediction method is reasonable and reliable. The results provide new perspectives and standpoints to objectively characterize the equilibrium moisture status of unsaturated clay subgrade.