To　gain　a　deeper　understanding　of　the　fundamental　characteristics　of　internal　forces　and　deformations　in　the　directional　distribution　of　granular　materials,　it　is　necessary　to　investigate　the　directional　distribution　of　particles　on　the　mechanical　properties　and　microstructural　evolution　process　of　the　soil.　The　discrete　element　particle　flow　program　PFC3D　is　used　to　construct　the　particle　with　the　same　aspect　ratio,　convexity,　and　sphericity　as　the　binary　images,　and　the　specimens　with　directional　particle　distributions　of　0°,　30°,　45°,　60°,　and　90°　are　generated.　Furthermore,　the　quantitative　correlations　between　the　constitutive　parameters　and　the　deposition　angle　are　examined.　The　results　show　that　the　shear　strength　and　shear　expansion　of　the　soil　increase　with　increasing　deposition　angle.　With　an　increase　in　axial　strain,　the　dominant　direction　of　contact　points　and　the　direction　of　force　chain　and　normal　contact　force　rotate　counterclockwise.　In　the　critical　state,　the　microstructural　direction　of　the　specimens　with　different　deposition　angles　is　approximately　the　same,　which　is　primarily　along　the　direction　of　45°　+　cs.　The　critical　friction　angle　decays　as　a　power　function　with　the　increase　of　deposition　angle　in　undrained　tests.　The　critical　void　ratios　of　the　specimens　with　different　deposition　angles　under　drained　tests　decay　linearly　as　the　deposition　angle　increases.　The　critical　mechanical　coordination　number　decays　exponentially　with　an　increase　in　deposition　angle　under　undrained　tests.　The　conclusions　mentioned　above　serve　as　a　guide　for　revising　the　constitutive　equations　for　specimens　considering　the　microscopic　behavior.　©　The　Author(s)　2024.