Experimental study on the microstructure and mechanical behaviors of leachate-polluted compacted clay

The intent of this article is to investigate the microstructure characteristics and macroscopic mechanical behaviors of leachate-polluted compacted clays. X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry were used to observe the mineral component, microstructure of the compacted clays polluted by different concentrations of landfill leachate. One-dimensional swelling test, direct shear test, and permeability test were conducted to measure and analyze the swelling properties, shear strength, and permeability of leachate-polluted compacted clays. Results indicated that the leachate pollution caused a decrease in smectite content of compacted clays. Aggregate structure was destroyed by leachate pollution, causing an increase in the relative porosity of the smaller pores and a decrease in that of the larger pores. However, the total porosity increased with the leachate concentration because of the decrease in swelling deformation of compacted clay. Leachate pollution caused a significant increase in cohesion and a slight increase in internal friction angle of the compacted clays. Moreover, the permeability of the leachate-polluted compacted clays decreased with the increase in time and leachate concentration.