To　validate　the　feasibility　of　the　construction　technology　of　mechanized　construction　for　wastewater　pump　room　in　shield　tunnel　and　the　reliability　of　the　bottom　sealing　concrete　of　the　pump　room,　an　indoor　test　is　designed　to　simulate　and　validate　the　safety　of　the　bottom　sealing　concrete　slab　in　the　high　water　pressure　deep　stratum　environment.　Then,　three-dimensional(3D)　finite　difference　software　FLAC3D　is　employed　to　build　a　3D　numerical　model　to　simulate　the　bottom　sealing　situation.　The　FLAC3D　internal　contact　element　is　used　to　simulate　the　contact　surface　between　the　bottom　sealing　concrete　and　the　outer　shield　body,　and　further　examine　the　influence　of　considering　the　contact　on　the　calculation　results　of　the　model.　The　results　show　the　following:　(1)　The　design　of　simulation　system　is　reasonable,　the　test　results　of　mechanized　construction　of　pump　room　bottom　sealing　test　in　main　shield　tunnel　can　meet　the　expected　requirements,　and　the　mechanized　bottom　sealing　grouting　can　meet　the　design　requirements,　indicating　the　feasibility　of　the　technology.　(2)　The　contact　surface　has　a　great　influence　on　the　calculation　results　of　the　model,　resulting　in　a　better　prediction　of　the　force　of　the　contact　surface.　(3)　Generally,　the　underground　water　pressure　in　the　actual　project　is　far　lower　than　the　test　one,　the　results　of　the　indoor　test　and　numerical　simulation　have　a　certain　safety　reserve,　and　the　sealing　technology　of　the　mechanized　construction　of　pump　room　is　feasible　in　the　actual　project.　©　2022,　Editorial　Office　of　Tunnel　Construction.　All　rights　reserved.