Tunnels　play　an　essential　role　in　the　transportation　network.　Tunnel　entrances　are　usually　buried　at　a　shallow　depth.　In　the　event　of　an　internal　explosion,　the　blast　pressure　will　cause　severe　damage　or　even　collapse　of　the　tunnel　entrance,　paralyzing　the　traffic　system.　Therefore,　an　accurate　assessment　of　the　damage　level　of　tunnel　entrances　under　internal　blast　loading　can　provide　effective　assistance　for　the　anti-blast　design　of　tunnels,　post-disaster　emergency　response,　and　economic　damage　assessment.　In　this　paper,　four　tunnel　entrance　specimens　were　designed　and　fabricated　with　a　scale　ratio　of　1/5.5,　and　a　series　of　field　blast　tests　were　carried　out　to　examine　the　damage　pattern　of　the　tunnel　entrances　under　internal　explosion.　Subsequently,　static　loading　tests　were　conducted　to　obtain　the　maximum　bearing　capacity　of　the　intact　specimen　and　residual　bearing　capacities　of　the　post-blast　specimens.　After　that,　an　explicit　non-linear　analysis　was　carried　out　and　a　numerical　finite　element　(FE)　model　of　the　tunnel　entrance　under　internal　blast　loading　was　established　by　adopting　the　arbitrary　Lagrangian-Eulerian　(ALE)　method　and　validated　based　on　the　data　obtained　from　the　field　blast　and　static　loading　tests.　A　probabilistic　vulnerability　analysis　of　a　typical　tunnel　entrance　subjected　to　stochastic　internal　explosions　(assuming　various　charge　weights　and　detonation　points)　was　then　carried　out　with　the　validated　FE　model.　For　the　purpose　of　damage　assessment,　the　residual　bearing　capacity　of　the　tunnel　entrance　was　taken　as　the　damage　criterion.　The　vulnerability　curves　corresponding　to　various　damage　levels　were　further　developed　based　on　the　stochastic　data　from　the　probabilistic　vulnerability　analysis.　When　the　charge　weight　was　200　kg,　the　tunnel　entrance　exhibited　slight　or　moderate　damage,　while　the　tunnel　entrance　suffered　severe　or　even　complete　damage　as　the　charge　weight　increased　to　1000　kg.　However,　the　tunnel　entrance＇s　probability　of　complete　damage　was　less　than　10%　when　the　TNT　charge　weight　did　not　exceed　1000　kg.