Geotechnical properties of tropical residual soils for sustainable landfilling

Abstract

To select a site for sanitary landfilling, it is paramount that geotechnical analysis is conducted to acquire relevant data for the purpose of studying soil properties. One of the basic requirements for the landfill site selection process is geotechnical criteria. This ensures that the chosen sites are founded on an impermeable soil deposit having adequate geotechnical characteristics that is also socially acceptable, economically cheap, and environmentally friendly. Geotechnical properties investigated in the laboratory for three sites samples comprises volumetric shrinkage, shear strength, and permeability. Groundwater contamination comes because of leachate. As such soil meant for landfill sites must have exceptional geotechnical properties able of restraining these leachates. Consequently, landfill soils must possess excellent ability to retain leachate in terms of permeability, an acceptable shear strength to withstand the waste load, and appropriate volumetric shrinkage to refute wetting and drying seasonal variations. The physical properties which showed that site A has a fines content of its soil up to 51%, site B with 29% and site C with 14%. Engineering property showed that site A has the lowest permeability of 2.1 x 10-9 m/s, followed by site B with 2.08 x 10-8 m/s, and then site C with the highest permeability of 1.5 x 10-7 m/s at OMC. The results show that only site A achieved maximum regulatory range of permeability value of 10-9 m/s. This implies that site A is the most suitable and sustainable, then followed by site B and then site C.