Methodology for prediction of desiccation of clay liners

摘要

Compacted clays are being used as liners in landfills and other waste containment facilities as barriers to water and contaminant flow. Extensive research on long term behaviour of clay liners established that clay liners over a period of time, under various environmental conditions such as leachate soil interactions and temperature tend to desiccate, resulting in cracks in the liner, affecting their performance significantly. Desiccation behaviour of clays is affected primarily by variations in suction pressures induced due to physico-chemical changes and temperature. There remains a need to determine the range of suction pressures developed under different degrees of compaction at temperatures comparable to leachate conditions. In this paper, soil water characteristics of compacted clays represented by van Genuchten parameters available in literature are used and variations in suction pressures are evaluated by a one dimensional coupled transport model of water, water vapour and temperature. Variations in suction pressures and shear strength properties of clay liners are related and a methodology for prediction of onset of desiccation is developed.