Volumetric shrinkage of compacted soil liner for sustainable waste landfill

Abstract

One of the main principal sources that contributes to the release of leachates in the environment is the municipal solid waste in landfill facilities. To mitigate the negative effects of leachate, landfill liner is constructed to provide a protective barrier that will not allow the leachate to pass through the compacted soil, which may cause groundwater contamination. Due to seasonal variation in tropical regions, compacted or natural soil liners tend to lose moisture when dry. This result to volumetric shrinkage, which causes cracks that affect the engineering properties and performance of the soils. Groundwater can easily be affected by leachate permeating through these cracks in soils because of desiccation induced by volume change. This paper aims to evaluate the effect of fines content at various gradation and moulding water content on volumetric shrinkage property of compacted laterite soil; and to compare the results with the regulatory standard for compliance to mitigate the negative effects of leachate on the environment. The technique used in this study was to vary the gradation of laterite soil at different moisture contents to achieve a sustainable result. It is observed that the volumetric shrinkage increase as the percentage of fines content increase with corresponding water content. The changes in volumetric shrinkage with time shows a sharp increase within the first five to ten d of drying and then become constant. The soil needs to be compacted on the dry side of optimum moisture content or at the optimum moisture content in order to meet the regulatory criteria of ≤ 4 %.