The Effect of Waste Leachate on the Strength Parameters of Clay with High and Low Plasticity

The leachate may cause negative effects on the mechanical behavior of contaminated soil. The objective of this research was to study this effect through performing consolidation and shearing experiments. The samples with different pollution contents underwent direct shear and consolidation tests in bot long-term short-term conditions. The shear strength and oedometric behavior of contaminated specimens was compared with non-contaminated specimens. In order to study the effect of pollution duration, and the length of soil exposure to leachate, the experiments were conducted at certain time intervals after contaminations of specimens. The samples were kept at barred packages and then tested at the required time. The result show that permeation of leachate into the soil pores leads to decrease in shear strength and increase in settlement. The result also shows that long term exposure of specimens by leachate with low concentration shows the same results observed for specimens exposed to high concentrated leachate in a short period of time. In other words, leachate even in small concentrations have major long-term drawbacks on shear strength and compressibility of soil. Therefore, the leachate will affect the performance of structures relied on such soils.