Suitability of expansive soil to use as clay liners in arid zone of Sri Lanka

Abstract

Solid waste is a growing problem in urban areas of Sri Lanka and management of waste, both liquid and solid have become a critical environmental concern due to the absence of engineered methods of disposing waste. Development of a simple engineered landfill facility utilizing a locally available material to suit landfill liner requirements is the most economical and the timely solution to this problem. In the present study, it was investigated the suitability of expansive soil which is commonly available in the south arid zone of Sri Lanka to use as clay liners in landfill facilities. The soil was improved by the addition of commercially available Bentonite to build a low hydraulic conductivity barrier. Further, the long term effect of soil -leachate interaction on hydraulic conductivity of the suggested liner was studied. Results showed that the engineering properties of expansive soil can be improved by the addition of bentonite to meet the landfill liner requirements. However, the original engineering properties of soil-bentonite mixtures were significantly affected by the leachate interaction over a period of time.