Shear strength of a pressure leachate-contaminated soil

Disposal Sites are considered the most popular for solid waste treatment in various countries. Landfilling has become the most frequent method applied worldwide to dispose of municipal solid waste. The existence of these solid waste processing activities produces leachate waste. This pollutant will absorb into the soil beneath the disposal landfill and affects soil characteristics physically and mechanically. The recent study analyzed the physical and mechanical properties of the soil contaminated by leachate with the percentage of 2.5%, 5%, 7.5%, and 10%. Tests of physical properties include moisture content, unit weight, specific gravity, Atterberg limits, and grain distribution. Test of standard Proctor and Direct Shear is also developed. The results show that unit weight, specific gravity, and Atterberg limits of contaminated soil decrease, while the moisture content and grain distribution increase as the leachate percentage increases. The optimum moisture content and maximum dry unit weight decreased for contaminated soil compared to the original soil. Direct shear strength tests were carried out on actual and diluted soil samples. The results show that leachate waste pollution reduces the shear strength of the soil. As the level of leachate pollutant gets higher, the cohesion (C) and the angle of internal friction (φ) of soil decline. For 10% leachate contamination, the shear strength of soil drops up to 50%.