The Effect of Heavy Metal Contaminants on the Strength Parameters of Sandy Clay

Document Type : Research Article


Technical faculty, University of Mohagheghe Ardabili, Ardabil, Iran


Desirable physical and behavioral characteristics of clay soils have resulted in their wide usage in engineering landfills. Clay soils are able to interact with the materials in contaminants thanks to their special mineral structure and adsorb part or all of the hazardous materials present in the leachate leaked in them. Previous studies have shown that changes in the physical and chemical characteristics of pore fluid in soil, given the type of minerals clay soils and the soil structure, significantly influence the properties of soil engineering including shear parameters, the extent of swell, and water adsorption percentage. The aim of this research is to study the effect of heavy metal contaminants on some strength and geotechnical parameters of sandy clays. For this purpose, following preparation of the samples, adsorption and direct shear experiments along with determination of the liquid limit were performed on the samples which had been exposed to the heavy metal contaminants of Pb and Zn. The results indicated that across the three studied clay types (the mixed sand kaolinite samples with different sand percentages), with the increase in the concentration of both contaminants, soil cohesion diminishes, while the internal friction angle of the samples was not affected by presence of heavy metal contaminants. When concentration of Zn increases to 25 cmmol, cohesion of samples with 90% and 60% of kaolinite decreased 20% and 23% respectively. While in the presence of Pb decrease in cohesion is 42% and 51%.


Main Subjects

[1] R.N. Yong, Geoenvironmental engineering: Contaminated soils, pollutant fate, and mitigation, CRC press, (2000).
[2] K. Mitchell James, Fundamentals of soil behavior, (1993).
[3] K. Soga, J. Mitchell, Fundamentals of soil Behavior, John Wiley& Sons, Hoboken, New Jersey, USA, (2005).
[4] J.C. Miranda-Trevino, C.A. Coles, Kaolinite properties, structure and influence of metal retention on pH, Applied Clay Science, 23(1-4) (2003) 133-139.
[5] R.N. Yong, A.-M.O. Mohamed, B.P. Warkentin, Principles of contaminant transport in soils, Elsevier Science Publishers, (1992).
[6] P.V. Sivapullaiah, Kaolinite–alkali interaction and effects on basic properties, Geotechnical & Geological Engineering, 23(5) (2005) 601-614.
[7] J. Jang, J. Bae, E. Park, Selective Fabrication of Poly (3, 4-ethylenedioxythiophene) Nanocapsules and Mesocellular Foams Using Surfactant-Mediated Interfacial Polymerization, Advanced Materials, 18(3) (2006) 354-358.
[8] V. Ouhadi, Z. Sharifian, Compare the effect of alkali metal contaminants and heavy metals on the plastic properties of kaolinite and bentonite clay, in: First Natinal Conference on geotechnical engineering, Mohaghegh Ardabili University, Technical Faculty, Iran, 2015.(In persian)
[9] H.-Y. Fang, J.L. Daniels, Introductory geotechnical engineering: an environmental perspective, CRC Press, (2006).
[10] V. Ouhadi, A. Haghayegh, H. Bayeste, The effect of heavy metal contamination on performance of sand-bentonite mixture (SEB) in landfill, Modares technical and engineering journal, 33 (2008). (In persian)
[11] E. Polidori, Relationship between the Atterberg limits and clay content, Soils and foundations, 47(5) (2007) 887-896.
[12] H. Novais-Ferreira, THE CLAY CONTENT AND THE SHEAR STRENGTH IN SAND CLAY MIXTURES, in: Soil Mech & Fdn Eng Proc,South Africa, (1971).
[13] E. Bayoglu, Shear strength and compressibility behavior of sand-clay mixtures, M. Sc. thesis, Department of Civil Engineering, Middle-East Technical, (1995).
[14] V. Ouhadi, R. Yong, M. Sedighi, Influence of heavy metal contaminants at variable pH regimes on rheological behaviour of bentonite, Applied Clay Science, 32(3) (2006) 217-231.
[15] W.R. Roy, Technical Resource Document: Batch-type procedures for estimating soil adsorption of chemicals, Office of Solid Waste and Emergency Response, US Environmental Protection Agency, (1992).
[16] M. Banimahd, S. Yasrobi, P. Woodward, Artificial neural network for stress–strain behavior of sandy soils: Knowledge based verification, Computers and Geotechnics, 32(5) (2005) 377-386.
[17] G. Obuzor, J. Kinuthia, R. Robinson, Soil stabilisation with lime-activated-GGBS—A mitigation to flooding effects on road structural layers/embankments constructed on floodplains, Engineering Geology, 151 (2012) 112-119.
[18] V. Ouhadi, M. Amiri, A. Goodarzi, The special potential of nano-clays for heavy metal contaminant retention in geo-environmental projects, Civil Engineering Infrastructures Journal, 45(6) (2012) 631-642. (In Persian)