The　tunnel　face　stability　is　a　key　issue　to　ensure　the　engineering　safety.　Combined　with　model　tests　and　numerical　simulations,　this　paper　focuses　on　progressive　settlement　characteristics　of　sandy　cobble　strata　for　shield　tunnels　during　the　instability　process.　Burial　depths　are　the　main　parameter　in　this　study,　and　ratios　of　burial　depth　and　tunnel　diameter　were　set　as　0.5,　1.0　and　2.0,　respectively.　The　results　show　that　the　surface　settlement　value　decreases　with　the　increase　of　the　burial　depth　ratio.　In　addition,　the　time　of　local　instability　is　negatively　correlated　with　the　burial　depth　ratio.　The　soil　disturbance　range　of　tunnel　face　instability　with　relatively　large　burial　depth　is　significantly　smaller　than　that　with　small　burial　depth.　This　provides　a　reference　for　the　research　on　the　strata　deformation　caused　by　the　instability　of　the　tunnel　face　in　the　sandy　cobble　strata.