Regression Analysis of Small Strain Shear and Constrained Modulus Measurements on Sands with Fines: Effect of Different Void Ratio Functions Used

The article is focused on a regression analysis of small strain shear and constrained modulus measurements of 15 different natural sands with plastic fines from the Pannonian basin. Measurements done within this work are supported by additional data on sands with plastic and non-plastic fines gathered from the literature in order to demonstrate the versatility of the approaches used and behavior observed. Bender / extender element techniques are used in this study for measuring the small strain shear and constrained modulus of sands with fines. Three void ratio functions, which are commonly used in predictive empirical equations for predicting small strain stiffness, with corresponding fitted parameters are presented, and their effect on the accuracy of the regression procedure is studied. It is assumed that all the void ratio functions tested provide nearly the same degree of accuracy and that the fitted models are able to predict the values of the parameters measured within an acceptable range of errors. Finally, proposed constant regression constants for sands with plastic fines are given.