Dynamic Properties of Sandy Soils at Large Shear Strains with Special Reference to the Influence of Non-Plastic Fines

This paper presents the results of the dynamic properties such as shear modulus and damping ratio of sandy soils, especially at large shear strain levels (>0.2%). A series of strain controlled cyclic triaxial tests were carried out on sand samples collected from the earthquake affected areas of Gujarat, India. Laboratory investigations were conducted on natural sand (Base sand) and clean sand samples. The shear modulus and damping ratios have been estimated based on the first cycle information. The effect of different parameters such as number of loading cycles, relative density, confining pressures, and non-plastic fines on the dynamic properties of the soils has been studied. It was observed that shear modulus decreases with an increase in the percentage of non-plastic fines. However, a slight increase in damping ratio was observed with increase in non-plastic fines.