Longyou　Grottoes,　the　underground　projects　with　a　rich　history　of　thousands　of　years,　are　one　of　the　key　cultural　relics　to　be　protected　in　China　and　are　actively　preparing　to　apply　for　a　world　cultural　heritage　site.　However,　due　to　the　shallow　buried　argillaceous　siltstone　with　low-strength　bedding　planes,　some　cavern　roofs　experienced　apparent　breakages　or　large-scale　collapses.　Clarifying　the　roof　deformation　and　failure　mechanism　is　essential　for　the　long-term　protection　of　the　historical　relic　and　sustainable　development　of　tourism.　Productive　previous　work　proved　that　three-point　bending　tests　of　rock　samples　could　reproduce　stress　states　of　cavern　roofs.　Therefore,　three-point　bending　numerical　models　with　various　bedding　plane　structures　for　Longyou　argillaceous　siltstone　are　created　in　this　study　to　investigate　the　rock　mechanical　behaviors.　The　simulation　results　show　that　as　bedding　mechanical　properties　decrease,　the　bending　strength　(BS)　has　a　slow　to　fast　decrease,　indicating　that　timely　protection　in　Longyou　Grottoes　before　the　BS　drops　sharply　is　conducive　to　preventing　roof　failures.　This　declining　trend　is　further　accelerated　when　the　bedding　dip　angle　changes　from　horizontal　to　vertical.　Dip　angles,　mechanical　properties,　and　spacings　of　bedding　planes　control　fracture　modes　of　models.　Moreover,　the　fitted　Gutenberg-Richter-type　relationships　between　acoustic　emission　(AE)　moment　magnitudes　and　logarithmic　AE　events　present　high　average　activity　levels　and　high　proportions　of　large　AE　events　in　both　bedding　planes　and　rock　matrix　for　models　with　strong,　dispersedly　distributed,　and　near-horizontal　bedding　planes.　In　summary,　the　simulation　results　reveal　the　impacts　of　transverse　isotropy　in　surrounding　rocks　on　roof　bending　failures,　which　may　provide　a　valuable　reference　for　the　reinforcement　and　protection　of　Longyou　Grottoes.