Geotechnical properties of the soils contaminated with oils, landfill leachate, and fertilizers

Severe modification of geotechnical properties of soils mainly occurred due to physical and/or physicochemical interactions between soil and contaminants such as oils, landfill leachate, and fertilizers. However, the degree of natural soil alteration in terms of permeability, shear strength, compaction, Atterberg limits, consolidation, and compressibility is dependent on contaminant and soil type. A sharp reduction in natural soil permeability occurred due to the migration of particle fragments of the contaminant and clogging the pores between soil particles. Nevertheless, the permeability of the contaminated soil with acidic and alkaline solutions could be increased due to the dissolution of the soil minerals. Physical and physicochemical interactions are predominant in granular and fine-grained soils, respectively. Atterberg limits of the natural soil are deteriorated due to physicochemical interaction with contaminants. Moreover, some contaminants tend to reduce the thickness of the diffuse double layer (DDL), resulting in soil shrinkage and causing a decrease in repulsive forces, thus promoting flocculation of particles.