Initial Shear Modulus of Sand-Fines Mixtures

This paper presents the dynamic properties of sand-fines mixtures based on the results of undrained cyclic triaxial tests. The sand was obtained from Sabarmati River, and three types of fines F1, F2, and F3 were obtained from locally available fine grained soils i.e. Suddha soil, Black cotton soil, and Bentonite soil. Sand-fines mixtures of wide range of plasticity from non-plastic to highly plastic mixture with PI=86 were prepared using the fines passing 75μ size. The initial shear moduli of all sand-fines mixtures are examined in terms of fines content and conventional plasticity index (IP). In the present investigation, a term equivalent plasticity index (IP*) has been defined by considering the plasticity characteristics of soil passing 2 mm size IS sieve on the same lines of. There is better correlation between the initial shear modulus of sand-fines mixtures and equivalent plasticity index (IP*) compared to conventional plasticity index (IP). An empirical equation for predicting initial shear modulus is proposed based on equivalent plasticity index and mean-effective stress.