Experimental study on small-strain shear modulus of rubber-clay mixtures

In order to study the dynamic deformation characteristics of rubber-clay mixtures, resonance column tests were conducted on mixtures with different rubber contents, rubber particle sizes, and confining pressures. The development patterns of dynamic shear modulus G and damping ratio lambda, were analyzed. A calculation method for skeleton void ratio esk expressing the contact state of mixtures was proposed based on the binary medium model. Furthermore, the maximum dynamic shear modulus G(max) of mixtures was evaluated based on skeleton void ratio e(sk). The results show that adding rubber particles leads to a decrease in G and increase in lambda. As the rubber content increases, G decreases and lambda, increases. Additionally, G increases and lambda, decreases with increasing confining pressure. Moreover, G increases and lambda, decreases with increasing rubber particle diameter. With an increase in rubber content, the skeleton void ratio e(sk) increases and G(max) decreases. At the same rubber dosage, as the rubber particle size increases, e(sk) increases and G(max) rises. Based on Hardin's formula, a characterization model of G(max) considering rubber content and rubber particle size is proposed using skeleton void ratio e(sk). The model exhibits good accuracy and can serve as a basis for evaluating G(max) of rubber-clay mixtures.