As　a　new　type　of　environmentally　friendly　lightweight　composite　material,　rubber　sand　mixture　has　a　wide　application　prospect　in　the　field　of　engineering　vibration　isolation.　In　order　to　reveal　the　variation　law　of　dynamic　characteristics　of　different　rubber　sand　mixtures,　based　on　the　dynamic　triaxial　test,　the　effects　of　rubber　content　and　confining　pressure　on　the　backbone　curve,　dynamic　shear　modulus　and　damping　ratio　of　mixtures　were　studied.　The　results　showed　that　with　an　increase　in　the　rubber　content,　the　backbone　curve　of　rubber　sand　mixture　had　a　trend　of　＇　ductile　failure　＇　and　the　dynamic　shear　modulus　of　mixture　decreased.　The　nonlinear　coordinated　variation　could　be　found　between　the　damping　ratio　and　rubber　content　with　a　characteristic　threshold　of　40　%.　The　mechanical　properties　of　rubber　particles　may　be　influenced　by　changing　the　type　of　＇　skeleton　structure＇　inside　the　sample.　©　2023　IABSE.　Published　by　American　Chemical　Society.