Prof. D. N. Singh

A. DALINAIDU

Ph. D.
Indian Institute of Technology Bombay, Powai, India naidu@ce.queensu.ca

CRACKING CHARACTERISTICS OF FINE-GRAINED SOILS

Population explosion and rapid industrialization have lead to generation of large amount of solid and liquid wastes, which contain high concentrations of toxic heavy metals. These wastes pose a great threat to the geoenvironment and challenge to engineers and planners for safe disposal and containment. With this in view, efforts are being made by researchers to develop methodologies for demonstrating the utility of various industrial by-products (viz., fly ash, cenospheres, ground granulated blast furnace slag etc.) for their application as an immobilizing agent for various geomaterials (viz., soils and rocks). However, the efficiency and proper selection of the immobilizing agent, primarily, depends on its sorption and desorption characteristics, which are quite complicated and challenging to determine. This necessitates extensive laboratory investigations by varying the parameters that influence sorption and desorption characteristics of these materials, directly or indirectly.
With this in view, investigations were carried out to establish sorption and desorption characteristics of various geomaterials and immobilizing agents by conducting batch and column tests. It has been demonstrated that column tests simulate 'geomaterial-contaminant-immobilizing agent interaction' in a much realistic way as compared to batch tests. However, as hydraulic conductivity of geomaterials is quite low, column tests would require large duration to yield sorption and desorption characteristics of these materials. With this in view, the utility of accelerated physical modeling, using a geotechnical centrifuge, for determining sorption and desorption characteristics of these materials in an extremely short duration has also been demonstrated.