Prof. D. N. Singh

BHINI RANI CHANDAN MALAGAR

M.S. (by Research)
Indian Institute of Technology Bombay, Powai, India BHEENIRANI@GMAIL.COM

INVESTIGATIONS ON PHASE CHANGE PHENOMENA IN SANDY SEDIMENTS

Transformation in the phases of a geomaterial could be attributed to various physical (viz., formation of ice), chemical (viz., dissolution of coral reefs) and/or biological (viz., microbial calcite precipitation, decomposition of the municipal solid waste etc.) processes. Formation of methane gas hydrates (MGHs) is one example which illustrates evolution of a multi-phase geomaterial in the sediments that are located in marine or permafrost regions. The major challenge associated with exploiting energy from MGHs is to model the mechanisms associated with the formation and dissociation of MGHs in the sediments. With this in view, and to explore the domain of multi-phase mechanics of the geomaterials, a comprehensive synthesis of the existing literature on HBS has been performed. This lead to the realization that apart from the prevailing thermodynamic conditions, sediments and their matrix (viz., particle size, pore-size, initial water saturation, salinity and mineralogy), influence the amount of MGHs formed and the rate of their formation & dissociation. To simplify the prevailing intricacies, and to develop a methodology that would reveal the phase change in the sediments during their exposure to low temperatures, freezing of water and saturated sediments was monitored with the help of time-domain reflectometry (TDR) and impedance spectroscopy (IS). It is believed that this preliminary attempt would be highly useful for deciphering the mechanisms that occur during the phase change of the multi-phase geomaterials.