Effect of expansive soils on swelling behavior of encapsulated sodium bentonite of geosynthetic clay liner (GCL)

Abstract

Due to the rapid urbanization of Indian cities, the generation of MSW is exponentially increasing. The confinement of the hazardous emission from a municipal solid waste (MSW) dumpsite is the major responsibility of management and engineers. Landfill gases and leachate generation are the results of chemical and biological activities in municipal solid waste and its decomposition process. The seepage control of leachate is a crucial aspect of MSW management. The flow of leachate to groundwater is one of the major causes of groundwater contamination resulting in human health risks nearby population. Geosynthetic clay liners (GCLs) are the most preferred options to restrict the flow of leachate from dumpsite to groundwater. GCL consists of sodium/ calcium bentonite as an encapsulated material between woven and non-woven carriers. The swelling behavior of sodium bentonite with low hydraulic conductivity makes it suitable to prevent the flow through it. In this study, the swelling nature of sodium bentonite was assessed in combination with expansive soils. The soils were collected from two different regions of Uttar Pradesh as Banda and Mahoba districts. The results showed that the swelling tendency of sodium bentonite can be enhanced by using specific proportions of expansive soils.