Effects of Drying-Wetting Cycles on Soil-Water Characteristic Curve

Abstract

Alternate drying-wetting cycle is considered to be one of the important factors that can affect the hydro-mechanical properties of soil. Due to the variability of climatic condition, soils are experienced by multiple drying-wetting cycles. But most of the previous studies on soil physical and mechanical properties are limited to a single drying-wetting cycle. This study is conducted to evaluate the effects of multiple drying-wetting cycles on SWCC. The microfabric changes are also studied by Scanning Electron Microscopy (SEM) which shows that soil particles are drawn closer together with increasing the drying-wetting cycles and led to a variation of microstructure. The SWCC results show that with increasing drying-wetting cycles the water content and water retention capacity decrease. The air entry value decreases with increasing drying-wetting cycles and the curves shift to the left. The impact of first drying-wetting cycle is more and decreases with subsequent cycles and reaches an equilibrium state after 4 drying-wetting cycles. The relationship between the van Genuchten model parameters and the number of drying-wetting cycles of investigated soil can be described by an exponential function.