عنوان مقاله [English]
Recently, the nano-materials have been used to improve soil properties. When the modified soil is used as the moisture and contaminant barriers in solid waste landfill liners, soil should minimize the flow of moisture and contaminants and should have acceptable geotechnical characteristics. In this study the effect of nano-clay material on the improvement of the characteristics of the Nazloo clayey soil of Urmia city, and Firoozkouh sand mixed with nano-clay, as the alternative soil in the absence of clayey soil, was investigated. For Nazloo clay, nano-clay caused the soil optimum water content and plasticity index to increase and the maximum dry density to decrease. For Firoozkouh sand, nano-clay did not have significant effect on the soil optimum water content but slightly increased the maximum dry density. The results of the hydraulic conductivity tests on Nazloo clay and Firoozkouh sand showed that the addition of nano-clay decreases the soils hydraulic conductivity. In Nazloo clay the hydraulic conductivity decreased to the standard level as for the landfill liner material but in Firoozkouh sand it did not decrease to the standard level. The results of the diffusion tests on Nazloo clay showed that nano-clay does not have significant effect on the soil chloride diffusion coefficient and this coefficient remains at its standard level. The results of this study showed that the addition of nan-clay has positive effect on the improvement of the soil geotechnical characteristics so that it could be used in the landfill liner construction; however, it does improve the Firoozkouh sand properties so that it can be used as alternative landfill liner material in the absence of clayey soil.