International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 11 Issue: 03 | Mar 2024
p-ISSN: 2395-0072
www.irjet.net
Geotechnical properties of Contaminated Soil Neelam Phougat1 and N Janakiraman2 1-2 Central Soil and Materials Research Station,
Olof Palme Marg, Hauz Khas, New Delhi-110016 ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Contaminated soil poses a great threat to the
literature suggests that before constructing building, road, bridge, embankment, dam etc. on contaminated soil, effect of contaminant on soil strength is to be studied. If suitable remedial measures and precautions are not undertaken, then contaminated soil may cause failure of structure built on it causing catastrophic damage [9].
environment and humans. There have been multiple sources of soil contamination including petroleum products, acid, alkali, salt, industrial effluents. Geotechnical properties of soil get modified on contamination with industrial wastes and garbage. Depending on the nature of contaminant, positive or negative effects of contaminant on the engineering properties of soils are possible. Detrimental effect of contaminated soil can cause foundation failures resulting in considerable damage to the structure built on it. On addition of some industrial waste such as textile effluent, engineering properties of soil get improved. In this review, effect of petroleum products, acids, alkalis, salts and industrial effluents on engineering properties of soil is being discussed.
Effect of some of the contaminant on geotechnical properties of soil is reviewed below:
2. CONTAMINATION WITH PETROLEUM AND REFINERY PRODUCTS: Geotechnical properties of soil get modified on contamination with petroleum and refinery products [1013]. Contamination of soil with crude oil has deteriorating effect on its strength, permeability, plasticity and swelling characteristics. Due to oil contamination, permeability, shear strength and Atterberg limits of CL soil got reduced. A direct correlation between oil content and angle of internal friction in CL soil and inverse correlation between oil content and angle of internal friction in SP and SM soils is reported by Mashalah et al. [14]. With increasing oil content in soil, cohesion is reduced due to loose packing of clay particles. On contamination with 16% of oil content, CL samples changed from hard consistency to soft consistency. In comparison to uncontaminated clay, aggregates of clay formed on contamination with diesel oil were having relatively loose packing of clay particles [15]. The contaminated clay behaves more like a cohesionless material. On getting permeated with heptanes, permeability of kaolinite was increased to about 1000 times.
Key Words: industrial waste, contamination, geotechnical properties, soil, petroleum products, acid & alkali, salt, industrial effluent
1. INTRODUCTION Large amounts of solid and liquid waste is generated due to industrial activities. Improper disposal of industrial wastes and garbage on to the land contaminates the soil and the ground water. The contaminant may be acids, alkali, salts, metals or organic matters [1-2]. Soil, being electrochemically active, reacts with contaminant. Physicochemical interaction of soil with contaminant modifies geotechnical properties of soil. Conventional geotechnical principles cannot be applied to contaminated soil. Extent of modification of geotechnical properties of soil due to contamination depend on the quantity and chemical composition of the contaminant, partition coefficient and mineralogy, pore fluid chemistry, permeability and adsorption properties of the soil [3 -6]. Contaminant changes the properties of soil by affecting the dielectric constant, electrolyte concentration, ion exchange capacity and thickness of diffuse double layer. With increase in dielectric constant, interparticle shearing resistance decreases and liquid limit and double layer thickness of soil increases [7,8].
The effect of motor oil contamination on the geotechnical characteristics of over-consolidated clay (CH) was studied by Nazir [16]. Atterberg limits were decreased significantly with increasing the duration of oil contamination up to first 3 months, after which, they remain constant due to stabilization of clay structure. The coefficient of permeability of contaminated clay increased significantly to three times the value for uncontaminated clay at low stress range of 100 and 200 kPa. At stress range higher than pre-consolidation stress, minor effect on the coefficient of permeability was reported on increasing the duration of contamination up to 24 months. The increase in permeability of contaminated clay is attributed to the reduction in the thickness of the double layer that surrounds the clay particle. Dielectric constant of motor oil is lower than that of water. Low dielectric constant of pore fluid of clay contaminated with
Detrimental effect of contaminated soil can cause extensive cracking damage to the floors, pavements and severe foundation failures resulting in considerable damage to structure built on it. Contaminant dissolved in rain water percolate the soil and damage foundation of buildings. Reduction of soil porosity and bearing capacity and increases in settlement due to soil contamination may result in failures of existing structures. The review of available
© 2024, IRJET
|
Impact Factor value: 8.226
|
ISO 9001:2008 Certified Journal
|
Page 1065