Rubber-sand mixture (RSM) has recently been demonstrated to be an environmental beneficial geotechnical material with wide application. The purpose of this paper is to investigate the stress-strain characteristics

volumetric properties and the modulus reduction properties of RSM. United tests combining triaxial shear and simple shear apparatus

in which 2 confining pressures and 7 rubber contents are considered

are conducted. Experimental results indicate that: with the increase of rubber content

the modulus of RSM decreases

and the stress-strain curves extend to strain hardening as well as the linearity of stress-strain relationship enhances. Volumetric expansion of RSM decreases and contraction increases with adding rubber to RSM. The behavior of stress-strain of RSM could be simulated well by extended Duncan-Chang hyperbola model

and the model parameters are evaluated with rubber content in RSM. With the increase of rubber content

the Gs -? curves (where Gs is static shear modulus and ? is shear strain) of RSM decrease while the generalized Gs /G0 -? curves (where G0 is initial shear modulus) shifts toward to large strain domain. The stress-strain relationship and volumetric strain-shear strain relationship obtained from triaxial shear tests and simple shear tests are consistent and verified each other. The stress condition and stress path influence the experimental parameters. The stress-strain curve and modulus curve obtained from triaxial shear tests are higher than that from simple shear tests

which is possibly induced by higher mean stress in triaxial shear tests. An empirical relationship between the initial modulus of RSM and the reducing rubber content is proposed based on experiments.