Effect of Particle Size, Moisture Content and Density on the Hyperbolic Model Parameters for Non-cohesive Soil

The hyperbolic non-linear elastic constitutive model for idealization of non-cohesive soil has been commonly used by researchers in numerical modeling of geotechnical problems. The hyperbolic model consists of several parameters such as modulus number 'K', exponent 'n', angle of internal friction 'phi' and failure ratio 'R-f', which are evaluated using laboratory shear test. The parameters 'K', 'n' and 'R-f' are evaluated from transformed stress-strain curve whereas 'phi' is directly evaluated from normal and shear stress. The study on 'phi' for various soil samples have been performed by many researchers whereas the variation of 'K', 'n' and 'R-f' for various soil samples have not been much explored in the literatures. In addition to it, the evaluation procedure of hyperbolic model parameters (HMP) is a very tedious task when samples are in large numbers. Therefore it is necessary to study the variation of HMP for various non-cohesive soil conditions and to propose certain correlations for its evaluation. The HMP are highly dependent on particle size, moisture content and density. Thus in order to study the influence of these factors on HMP, coarse, medium and fine sand as well as fine gravels with varying densities have been taken into consideration. The direct shear tests have been conducted in dry and moist conditions. The HMP have been evaluated for every samples and the effect of particle size, moisture content and density have been studied. It has been found that the influence of particle size is more than that of moisture content and density. Further the correlations have been developed for HMP with respect to particle size, moisture content and density. The correlations are useful in evaluation of HMP.