Dynamic properties of sand from dry to fully saturated states

Abstract

By using bender and extender elements test, the velocities of the primary and shear waves, Vp and Vs respectively, were measured for a sandy material by gradually varying the degree of saturation, Sr, between the dry and fully saturated states. The effect on the results of varying the relative density and effective confining pressure was also studied. The measurements clearly reveal that for a certain optimum Sr, which is around 0·7–0·9% for the chosen sand, the value of the shear modulus G reaches a maximum value, whereas the corresponding Poisson's ratio ν attains a minimum value. The values of the shear modulus corresponding to Sr ≈ 0% and Sr = 100% tend towards the same value. For values of Skempton's B parameter greater than 0·99, the values of Vp and ν rise very sharply to those of water. The predictions from Biot's theory with respect to the variation of Vp with Sr match well with the measured experimental data.