In　order　to　investigate　the　influence　of　face　instability　for　tunnels　with　different　burial　depths　in　sandy　cobble　strata　on　earth　pressure　and　the　instability　region,　geomechanical　model　tests　and　numerical　simulations　were　performed.　The　continuous　excavation　method　was　adopted　to　reduce　the　pressure　of　the　soil　bin　and　restore　the　real　engineering　situation.　Earth　pressure　in　three　directions　of　the　observation　section　in　front　of　the　tunnel　face　was　monitored　during　the　tunneling　of　the　shield.　Evolutions　of　the　lateral　stress　ratios　at　different　stages　were　also　investigated.　The　instability　area　of　the　shield　tunnel　face　in　sandy　cobble　strata　with　different　burial　depth　ratios　during　the　instability　stage　was　obtained　based　on　the　change　ratio　of　earth　pressure　and　compared　with　existing　researches.　The　earth　pressure　began　to　change　when　the　excavation　was　one　shield　diameter　away　from　the　observation　section,　and　when　the　excavation　reached　the　observation　section,　the　earth　pressure　decreased　significantly.　The　burial　depth　of　shield　tunnel　in　the　sandy　cobble　strata　has　a　significant　impact　on　the　evolution　of　soil　arch　and　the　size　of　the　failure　area.　The　numerical　simulation　of　the　continuum　medium　cannot　reflect　the　stress　redistribution　characteristics　of　the　granular　body　like　sandy　cobble　strata,　and　the　failure　area　or　stress　disturbance　area　obtained　by　the　model　test　is　larger　than　the　numerical　simulation　result.　Existing　methods　have　deviations　in　analyzing　the　failure　area　of　shield　tunnel　face　in　sandy　cobble　strata.　It　provides　not　only　guidance　for　shield　tunnel　excavation　engineering　in　sandy　cobble　strata,　but　also　a　reference　for　the　theoretical　research　on　failure　areas.