Effect of Sodium Chloride on Geotechnical Properties of Black Cotton Soil

ISSN: 2348-9812 Industrialization is very important for the socio economic development of the country. But, increase of industrialization causes lot of environmental hazards. Municipal solid waste and industrial solid waste placed on or beneath the ground surface are the two most important sources for subsurface contamination. During rains, water infiltrates into the waste and reacts physically, chemically and biologically with the waste to produce leachate. The leachate infiltrates into the ground causing subsoil and ground water contaminations. Generally, the solid waste continues to stay at the location where it is placed over the years, hence the process of leachate infiltration into the subsurface environment continues, slowly and for several years. Liquid wastes also seep or leak into the sub-surface soil and contaminate the subsurface soil and the ground water. Such industrial effluents either treated or untreated are discharged over the soil which may change the properties of soil. Therefore, it becomes very important to understand the effect of chemicals that are ejected out of the industries. If there is an improvement in engineering behavior of soil, there is a value addition to the industrial wastes serving the three benefits of safe disposal of effluent, using as a stabilizer and return of income on it. If there is degradation of engineering behavior of soil then solution for decontamination is to be thought of. The control of alkali induced heave in black cotton soil using potassium and magnesium salts was observed by Hariprasad Reddy, and noticed that the swelling characteristics of treated soil was in controlled condition when compared to untreated soil [1]. However the swelling here occurs in two stages, first stage can be controlled but the second stage of swelling cannot be controlled. The effect of certain industrial effluent on swelling characteristics of black cotton soil was investigated by Narasimha Rao et al. [3]. Textile, Tannery and Battery effluent were considered as the contaminants, it was observed that the Textile and Tannery effluent decrease the plasticity and swelling of expansive soil, whereas Battery effluent increases the same. The effect of industrial effluents with soil was represented by Narasimha Rao and Chittaranjan [4]. The effluent sample collected from an area around the textile industry in Manipal shows, higher metal concentration of Sodium, Calcium, Magnesium, Potassium and Iron was studied by Poornima K and Vasudevan K [7]. The effect of calcium chloride and Na2SiO3 on CH properties of soil, was studied by Ramadasu [9]. He noticed that, the liquid limit, plastic limit , plasticity index and swelling characteristics of soil has reduced with the increase in concentration of calcium chloride Na2SiO3, whereas the strength of the soil has increased with the increase in concentration of same. Further the effect of sodium chloride on geotechnical properties of black cotton soil was studied by Srikanth and Harnadh Introduction Rapid industrialization in the various fields of urbanization has resulted in massive pollution of environment. Pollution occurring in soil and ground water table is alarmingly increasing day by day. Thus, a sincere attention is required, to control the effect of pollutants on the soil and water table. An attempt was made here to know the effect of one such pollutant, i.e. Sodium chloride (NaCl) on black cotton soil. The soil was collected from Siraguppa taluk, Bellary district. It was subjected to the various concentrations of sodium chloride viz, 0.1normality (N), 0.5N, 1.0N, 2.0N, and 4.0N, and the effect on the index properties and engineering properties of soil was observed. It, was observed that the, values of liquid limit, plastic limit and plasticity index are decreasing with increase in the concentration of NaCl. The variation in the values of Optimum Moisture Content (OMC) was not well pronounced with the increase in the concentration of NaCl. However, the values of Maximum Dry Density (MDD) at higher concentrations are found to be increased. Also, the strength of the soil was found to be increased with increase in concentration of NaCl. Further, the consolidation test was conducted on black cotton soil with various concentration of NaCl viz. 0N, 0.5N, and 4.0N; to know the permeability of soil, and it was observed that the permeability was increasing with increase in concentration.