Effect of Soil Hydraulic Properties on Infiltration of Rainwater into Unsaturated Soil

Abstract

Infiltration of rainwater is a major reason for soil instability in Malaysia. Rainfall event, especially in a tropical country is considered to have high intensity and long duration which will change parameters such as pore water pressure and moisture content. The rate of infiltration depends on the basic soil properties and hydraulic properties. In this paper, the effect of soil hydraulic properties on the infiltration of rainwater is discussed. There are two types of soil used in this study, sandy soil and kaolin. Hydraulic properties such as hydraulic conductivity and soil water characteristic curve (SWCC) are defined for both types of soil. Then soil column apparatus with applied rainfall to the column is used to determine moisture content using time-domain reflectometry (TDR). The result shows that kaolin has more ability to withstand the water than sand. Kaolin soil has lower hydraulic conductivity value compared to sand soil. Other than that, volumetric moisture content value is increased when water flow is applied to the soil and decreased when flow is stopped, or during drying process.