A modified state parameter for sands

This paper presents arguments for using a modified state parameter, I_c, to describe the fundamental state of sand. The other reference state being the minimum void ratio is introduced in the expression of I_c in addition to the critical state. Shear properties of sands from a substantial body of triaxial tests were examined, showing better correlations with I_c than ψ, which was the original state parameter defined by Been and Jefferies (35(2):99–112, 1985). More importantly, the parameter (χ_c), introduced by the individual correlations with I_c, represents the limit values of sand properties associated with the sand densest state and the values of χ_c are within a justifiable range facilitating engineering applicability. The modified state parameter I_c can be readily incorporated into current constitutive models. This is demonstrated in the paper through the use of a new I_c based expression for dilatancy that captures better the response measured in triaxial compression, particularly when the loading is cyclic.