EXPERIMENTAL STUDY ON WETTING SOIL WATER CHARACTERISTIC CURVE OF SAND WITH MIXTURE OF BENTONITE CLAY

Abstract

Soil-water characteristic curve (SWCC) also known as water retention curve is an integral part of unsaturated soil mechanics. SWCC is a constitutive relation in unsaturated soil mechanics where soil suction is related to water content. Wetting SWCCs were determined for different sand-bentonite clay mixtures. With the help of the Van-Genuchten equation, acquired test data were fitted. Wetting SWCC can be related to flow of water through unsaturated zones of soil from the groundwater table to the ground surface. Negative column test was employed to determine SWCC since it is fairly simple and simulates the actual field conditions. In the present paper, different soil samples, where sand is mixed with varying proportions of bentonite clay are considered, for determining wetting SWCC. Finer the soil particle, higher will be the soil suction for a given water content. Hence, as the content of clay increases, SWCC slightly shifts towards the right, indicating the increment in soil suction. In turn, water entry value(WEV) also shoots up.