Experimental study on small-strain shear modulus of sand-silt mixtures by bender element testing

In order to investigate the influences of the fine content f c , relative density D r , and initial effective confining pressure σ' 3c on the small-strain shear modulus G max of sand-silt mixtures, a series of bender element tests were performed on saturated sand-silt mixtures with various f c , D r and σ' 3c . The test results show that, as f c increases, G max of the mixtures with D r = 35% or 50% first decreases and then increases slightly, while G max for D r = 60% case presents a decreasing tendency. σ' 3c causes an increase in G max with different f c at a given D r , and the growth rate of G max with σ' 3c remains basically unchanged. In addition, G max decreases with the increase of the void ratio at a fixed σ' 3c , and f c has a strong influence on the decreasing rate of G max at a constant σ' 3c . The testing results reveal that G max for a specified f c case can be estimated reasonably using the Hardin model. However, as f c increases, the best-fitting parameter A of the Hardin model first decreases and then increases. The modified Hardin model, considering the influences of f c , σ' 3c and e, can be used to predict G max for different types of sand-silt mixtures, and the errors of the predicted G max are basically less than 10%. © 2018, Editorial Department of Journal of Southeast University. All right reserved.