Maintaining　the　stability　of　the　tunnel　face　during　the　construction　of　the　submarine　shield　tunnel　is　the　prerequisite　for　safe　construction.　A　series　of　face　instability　model　tests　under　saturated　strata　were　carried　out.　The　earth　pressure,　the　evolution　of　the　soil　arch　area　and　the　amount　of　soil　entering　the　soil　groove　caused　by　the　instability　of　the　tunnel　face　under　different　face　water　pressure　conditions　were　studied.　A　series　of　numerical　simulations　were　carried　out　to　analyze　the　effects　of　tunnel　face　water　pressure.　The　results　show　that　the　vertical　earth　pressure　and　horizontal　earth　pressure　at　different　positions　show　a　gradual　decrease　with　the　increase　of　the　baffle　backward　distance,　and　the　smaller　the　water　pressure　ratio,　the　more　obvious　this　law　is.　According　to　the　test　results,　the　decrease　of　the　water　pressure　ratio　of　the　tunnel　face　can　significantly　increase　the　soil　intake　of　the　soil　tank,　which　indicates　that　the　collapse　range　above　the　tunnel　face　is　large.　The　trend　of　instability　region　obtained　by　numerical　simulation　is　consistent　with　the　test　monitoring　results.　This　provides　a　reference　for　the　construction　of　submarine　shield　tunnels.　©　2024