Effect of saturation on dynamic properties of compacted clay in a resonant column test

Abstract

ABSTRACTIn the present study, a series of resonant column (RC) tests was performed on compacted clayey soils to study the effect of saturation on the dynamic properties of soil, including shear modulus (G) and damping ratio (D). The Poisson’s ratio () of the compacted clays is also determined. Cylindrical samples measuring 50 mm × 100 mm were prepared in a constant volume mould at optimum moisture content under a static compaction. Two series of RC tests were performed; in the first series samples were compacted at optimum moisture content while in the second series, samples were fully saturated. A reduction in shear modulus and increase in damping ratio with saturation were observed. This is due to the suction present in the partially saturated soils. It was observed that this effect is noticeable at low isotropic confining pressures; however, it reduces considerably with an increase in isotropic confining pressure. Similar observations were made with respect to the shear strain applied. For the partially saturated soils, Poisson’s ratio decreases with an increase in confining pressure and increases with an increase in shear strain. However, Poisson’s ratio obtained for the saturated sample, as expected, is close to 0.5 and remains constant for all confining pressures and shear strains applied.