Date of Publication :30th December 2017

Abstract: Natural clay size soil particles are bigger than nanoparticles. Addition of nanoparticles in the presence of water modifies cohesion (c) and angle of internal friction(φ) of the clay soil. When organic materials are added the behaviour is different. If inorganic material is added the behaviour is entirely different. Available research documents show that in a soil sample the cohesion increases and internal friction decreases with increase in clay fraction or percentage. This is a normal geotechnical behaviour of clay and shear strength. But when organic fibres are added along with inorganic nano (Sio2) the geotechnical behaviour is entirely different. Both cohesion and angle of internal friction show an increasing trend. The normal association and dissociation adjustment between cohesion and angle of internal friction is followed in the presence of water and inorganic natural particles. If organic fibers are mixed geotechnical behavior is entirely different and abnormal. The paradoxical behavior of shear strength of clay (increase in cohesion c and increase of angle of internal friction φ ) is due to unnatural, manufactured nano Sio2 and fibres. The slope of the c,φ curve for natural soil material is opposite to the slope of soil with artificial additive fibres. The conclusions are: 1. The paradoxical behavior of shear strength of clay is interpreted and explained. 2. In c,φ curve the slope is different and opposite to the natural behavior of clay confirms the presence of pollutants like nano Sio2 or fibres or any other artificial organic additives. 3. The opposite slope helps to detect and estimate organic pollutants.

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