Influence of Shear Strain on the Poisson’s Ratio of Clean Sands

Abstract

In the present study, a series of resonant column tests was performed to determine the influence of confining pressure, shear strain and relative density on the dynamic properties and Poisson's ratio of poorly graded clean sand. The tests were performed on the sand specimens of size 50 × 100 mm compacted at relative densities 30, 50 and 75 %. To achieve the corresponding relative density, sand was compacted in 5 equal layers with a specific number of blows. A fixed-free type resonant column apparatus was used to determine the dynamic soil properties at various confining pressures. It has been inferred from the data that the shear modulus ($G$) increases with an increase in confining pressure and relative density; and decreases with an increase in shear strain. In addition, damping ratio ($D$) decreases with an increase in confining pressure and relative density; and increases with an increase in shear strain. In addition, Poisson’s ratio ($\nu$) decreases with an increase in confining pressure and relative density and increases with an increase in the shear strain. The variation of shear modulus with Poisson’s ratio is also discussed. It has been found that there has been a decrease in shear modulus with an increase in Poisson’s ratio of the soil. It is noticed that the small strain shear modulus determined from the present study closely matches with the value determined using the correlations from the literature.