This　study　investigates　the　strength　and　stress-strain　relationship　of　jointed　soft　rocks　using　undrained　triaxial　compression　testing.　A　bounding　surface　plasticity　model　considering　overconsolidation　and　structural　decay　is　proposed　for　jointed　soft　rocks.　Specifically,　a　bounding　surface　concept　is　introduced　for　overconsolidation.　A　new　structural　decay　formulation　is　derived　based　on　unified　strength　theory　to　model　the　effect　of　a　joint　plane　on　the　structural　strength.　A　new　hardening　law　considering　structural　decay　is　derived　and　verified　by　triaxial　compression　testing.　Finally,　the　model　applicability　is　demonstrated　by　triaxial　compression　testing　on　jointed　soft　rocks.