On evaluation of shear modulus parameter (G0) in SANISAND constitutive model

Abstract

The SANISAND constitutive model has been widely employed for the simulation of sands cyclic behavior. The shear modulus constant (G0) in SANISAND should be theoretically estimated from maximum shear modulus of soil (Gmax). To estimate G0, however, majority of calibration studies have used triaxial tests data in the shear strain levels larger than those associated with Gmax. This technical note aims to demonstrate how the selection criteria forG0 parameter affects the SANISAND model predictions , particularly in terms of G-reduction (shear modulus -shear strain) curve of sands. First, experimental G-reduction curves for four sands are compared with SANISAND predictions based on the values of G0 parameter estimated from triaxial tests. Then, a new calibration set of SANISAND for a single sand is proposed based on the G0 value estimated from Gmax, obtained from resonant column tests. The results confirm that the numerical shear stiffness values fall significantly lower than the experimental values in small strain ranges when the G0 constant is estimated from triaxial tests. However, the G0 constant estimated from Gmax appropriately predicts the experimental G-reduction curve of the sand in a wide shear strain range.