Study on Soil-Water Characteristic Curves of Unsaturated Silty Clay of an Old Landfill Cover

Abstract

In order to better understand the performance of silty clay under different conditions, an assessment of the water retention characteristics under different temperatures is required. Laboratory tests were carried out to measure the soil-water characteristic curves (SWCCs) of the silty clay at different temperatures by the filter paper method. The soil-water characteristic curves (SWCCs) in this study were shown in terms of moisture content, void ratio and degree of water saturation (S_r). Temperature has great influence on the SWCCs of the silty clay. Water retention capacity decreases with the increase of temperature, particularly at low suction range (0–500 kPa for matric suction). For a fixed suction value (e.g. 100 kPa), when the temperature increases from 20 to 60 °C, the water retention capacity of the soil decreases from 22.5% to 13.0%. It is also found that temperature has greater influence on matric suction for the case with S_r ≥ 0.2 than that for the case with S_r < 0.2. The curve indicated that the correlation between silty clay void ratio and suction is approximately linear. It is noted that the values of soil matric suction with temperature of 40 °C appeared to be larger than the case with 20 °C and 60 °C for a given void ratio.