Abstract: Rubber-sand mixture, as a kind of low-cost and environmental protection geotechnical material, has broad applications, and the research on its mechanical properties is of great significance. In this study, the combined test of shear wave and compression wave for rubber-sand mixture is carried out by bender-extender element method. The propagation time of shear wave and compression wave is determined by discrete frequency scanning method and initial arrival wave method, respectively. After that, the elastic dynamic parameters such as initial shear modulus, constrained modulus and Poisson's ratio, are obtained. The influence of rubber content and confining pressure on elastic dynamic parameters of rubber-sand mixture is analyzed as well. The results show that under the same confining pressure, with the increase of rubber content, the initial shear modulus and constrained modulus of rubber-sand mixture gradually decrease, and the initial Poisson's ratio gradually increases. Under the same rubber content, with the increase of confining pressure, the initial shear modulus and constrained modulus of rubber-sand mixture gradually increase, and the initial Poisson's ratio gradually decreases. Finally, the coupling effect of the two factors and the related mechanical mechanism are analyzed.

Key words: rubber-sand mixture (RSM), bender-extender element, elastic dynamic parameters, coupling effect, mechanical mechanism