The　Benoto　cast-in-place　piles　are　widely　used　in　civil　engineering　for　having　the　advantage　of　producing　low　vibration　and　noise.　Therefore,　more　researches　are　needed　to　fully　understand　its　mechanism.　However,　the　researches　on　the　mechanism　of　Benoto　piles　are　only　limited　to　the　driving　stage,　the　study　of　extraction　stage　of　the　steel　casing　is　not　comprehensive.　In　this　paper,　a　three-dimensional　numerical　model　was　developed　by　Coupled　Eulerian–Lagrangian　method.　The　mechanism　of　high-frequency　vibratory　extraction　of　casing　was　studied　in　detail.　The　result　indicates　that　the　vibratory　casing　extraction　process　can　be　divided　into　two　stages,　namely　the　slow　and　fast　extraction　stage.　During　the　vibratory　casing　extraction　process,　the　soil　displacement,　stresses,　void　ratio　and　excess　pore　water　pressure　abruptly　change　in　the　soils　around　the　casing　bottom.　Furthermore,　the　influence　of　vibratory　hammers　on　vibratory　casing　extraction　was　investigated.　The　change　in　the　excitation　frequency　and　excitation　force　has　effect　on　casing　extraction　speed　and　soil　particle　velocity,　but　hardly　has　any　influence　on　soil　displacement　and　stresses.　©　2017,　Indian　Geotechnical　Society.