Afsoon Soori - Former Graduate Student. Department of Civil Engineering. Azad University. Tehran. Iran
Hassan Negahdar - Professor. Department of Civil Engineering. Azad University. Tehran Markazi branch. Tehran. Iran
Ali Nabizadeh - Assistant Professor. Department of Civil Engineering. Shahid Rajae University. Lavizan Tehran. Iran
Mohammad Zeynali - Former Graduate Student. Department of Civil Engineering. Azad University. Tehran. Iran

By urban development and rapid industrial growth in the recent years and the activity of industrial heavy metals in different concentration can enter into the soil-water system. The penetration of heavy metals into the soil is not only one of the environmental problems it can also change some of the physical and mechanical properties of the soil such as compaction, consolidation, permeability and shear strength of soil. Clay soils are used in many construction projects due to their special physical and chemical properties. The aim of this study was to investigate the effect of lead nitrate infiltration on some geotechnical parameters of clay soils in Najmabad industrial town located in Alborz province in Iran. In this study the processing time of contaminated samples was considered to be ۷۲ hours. SEM and XRD tests have been performed on soil samples with different concentrations of lead. The results show that with increasing the concentration of lead in the soil, the liquid limit and plastic limit of the soil decreased, the maximum dry density increased, the optimum water content decreased and the cohesion of soil increased. By increasing the concentration of lead in the soil the angle of internal friction of the soil does not change regularly and significantly but the soil porosity ratio is reduced.

heavy metal, lead nitrate, clay soils, industrial towns, geotechnical properties