Acceptable Zone for Green Construction of Compacted Tropical Laterite Soil

Groundwater contamination caused by leachates in landfills has been a major concern in the tropical regions of the world. Where most of their municipal solid waste management is through landfilling either in open, control or sanitary. To mitigate the negative effects of leachate infiltration through soil barriers, a proper design with the required amount of soil fines content needs to be investigated. The general recommendation is to compact soil meant as hydraulic barrier on the wet side of optimum because it provides lower hydraulic conductivity. Though, care must be taken to ensure that the moulding water content is suitably chosen to balance between the volumetric shrinkage strain, unconfined compressive strength, and hydraulic conductivity. the reason is that higher moulding water content results to lower hydraulic conductivity, whereas it increases volumetric shrinkage and lowers shear strength. Therefore, a tropical laterite soil was reconstituted and subjected to laboratory tests to determine its suitability as compacted soil liner used in sanitary landfills. Three design parameters at their permissible limits were plotted using the dry density against moulding water content and obtained the overall acceptable zone. The overall acceptable zone was achieved at moulding water contents ranged between 24-28% for 50% fines content.