Prof. D. N. Singh

SREEDEEP SEKHARAN

Ph. D.
Indian Institute of Technology Bombay, Powai, India srees@iitg.ernet.in

MODELING CONTAMINANT TRANSPORT IN UNSATURATED SOILS

Recently, there has been an intense public and scientific concern over the disposal of solid and hazardous wastes, which adversely affect the quality of subsurface environment and the groundwater reserves. This necessitates studying interaction of these wastes with the geoenvironment and estimating their influence over it, in the long run. To achieve this, several studies were conducted in the past, which are mainly based on the assumption that the soil is fully-saturated. However, this assumption is not valid for most of the situations that are encountered in real life, where the soil is partially-saturated or unsaturated. Hence, systematic studies to establish fundamental characteristics of this state of the soil (viz., suction, hydraulic conductivity and clay content), which have been reported to be quite crucial for designing efficient barriers and waste containment systems, becomes essential.
With this in view, efforts were made to employ state-of-the-art instruments to characterize unsaturated soils and to evaluate efficiency of the existing models and methodologies, which are being used for establishing the soil-water characteristic curve by researchers. Efforts were also made to develop guidelines that can be employed for characterizing unsaturated soils without resorting to such cost-intensive instruments. In addition to this, a non-destructive methodology, based on the impedance response of the soil, was developed for studying the diffusion of contaminants in unsaturated soils.