This　paper　presents　a　new　approach　for　the　development　of　an　elastoplastic　constitutive　model　to　predict　the　strength　and　deformation　behaviour　of　soils　under　general　stress　conditions.　The　proposed　approach　was　based　on　characteristic　stress,　which　considers　the　effect　of　the　intermediate　principal　stress　on　the　material　strength.　Referring　to　the　Cam-clay　model,　the　shear　dilatancy　equation,　plastic　potential　function　and　hardening　parameter　for　the　developed　model　were　all　derived　using　the　characteristic　stress.　The　model　predictions　indicated　that　the　established　model　could　quantitatively　reproduce　the　negative　dilatancy　behaviour,　positive　dilatancy　behaviour,　and　three-dimensional　strength　properties　of　soils.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.