Dynamic properties of clean sand from resonant column studies

In this study a series of resonant column tests were performed on poorly graded clean sand to determine the shear modulus and damping ratio by varying confining pressure and shear strain. The sizes of the sand sample prepared were 50 100 mm. The tests were performed for a relative density of 75%. The confining pressures applied were 50, 100 and 200 kPa. The shear strain variation is made from 0.0001 % to 0.1 %. It has been inferred from the data that the shear modulus (G) increases with increase in confining pressure and decreases with increase in shear strain. In addition, damping ratio (D) decreases with increase in confining pressure and increases with the increase in shear strain.