Experimental Study on Physical and Mechanical Properties of Expansive Soil Polluted by Heavy Metals

Abstract

With the rapid development of economy, heavy metal pollution has brought serious harm to the engineering construction in expansive soil area. The Experimental study are to further reveal its physical and mechanical properties, and better guide the engineering practice. The effects of heavy metal ion concentration on compaction, permeability and unconfined compressive strength of expansive soils were studied by preparing 3 different concentrations of Pb2+ and Zn2+ polluted expansive soils in Nanyang city of Henan Province. The results show that with the increase of heavy metal ion concentration, the maximum dry density and permeability coefficient of contaminated soil increase, and the optimum water content and unconfined compressive strength decrease. At the same heavy metal ion concentration, lead-contaminated soil has a higher permeability coefficient and less unconfined compressive strength than zinc-contaminated soil. Compared with the lead contaminated soil, the maximum dry density of the dyed soil is larger and the optimal water content is smaller. The change of the dry density has a significant effect on the permeability coefficient, and the larger the dry density, the smaller the permeability coefficient. It can be seen that heavy metal pollution can change the physical and mechanical properties of expansive soil.