In　order　to　consider　the　stress　path　dependency　of　soils,　this　paper　decomposes　any　arbitrary　stress　path　into　several　infinitesimal　stress　paths.　Then　the　infinitesimal　stress　path　is　further　transformed　into　the　superposition　of　two　parts,　i.e.,　a　constant　stress　ratio　part　and　a　constant　mean　stress　part,　which　are　sufficiently　close　to　the　real　stress　path.　The　plastic　strain　increments　under　the　transformed　paths　are　determined　separately,　and　then　the　plastic　strain　under　any　path　is　obtained.　Based　on　the　instantaneous　loading　line　of　normally　consolidated　soil,　a　reference　state　line　is　proposed　to　determine　the　overconsolidation　ratio　and　creep　time　of　soil.　The　overconsolidation　ratio　is　introduced　into　the　viscous　flow　rule　to　obtain　the　viscous　strain　increment.　The　stress-strain-time　relationship　for　triaxial　compression　condition　is　extended　to　3D　stress　condition　by　the　transformed　stress　method.　The　proposed　model　adopts　only　seven　material　parameters　and　each　of　them　has　a　clear　physical　meaning.　Comparisons　with　test　results　demonstrate　that　the　model　can　not　only　reasonably　predict　the　plastic　strain　under　typical　stress　paths　of　excavation,　but　adequately　capture　the　time-dependent　behaviours　of　soils,　including　creep,　stress　relaxation　and　strain　rate　effect.