Comparison of small-strain shear modulus and Young’s modulus of dry sand measured by resonant column and bender–extender element

Abstract

The small-strain shear modulus and Young’s modulus of dry sand are simultaneously measured by resonant column and bender–extender element tests. Two different methods are adopted to calibrate the resonant column and the results indicate that the conventional calibration method may significantly underestimate the Young’s modulus obtained in flexural excitation, while it only slightly underestimates the shear modulus obtained in torsional excitation. A new calibration method that establishes a calibration curve based on the resonant frequency is used to overcome the error. With this new calibration method, the shear modulus and Young’s modulus from the resonant column agree well with those from the bender–extender element. It convincingly explains the reason why a very small Poisson’s ratio was observed in previous resonant column tests and suggests that the effect of resonant frequency on the calibration results must be considered in flexural excitation.