The　purpose　of　this　investigation　is　to　analyze　the　failure　probability　of　a　blast　in　a　shallow　RC　tunnel.　The　field　blast　tests　are　carried　out,　and　a　refined　finite　element　model　(FEM)　is　established　based　on　LS-DYNA.　To　account　for　blast　uncertainty,　the　Monte　Carlo　method　is　used　to　determine　150　blast　conditions.　A　failure　evaluation　method　based　on　a　mechanical　performance　index　is　proposed.　The　probabilistic　blast　demand　model　(PBDM)　and　the　probabilistic　blast　capacity　model　(PBCM)　are　established.　Finally,　a　probability　assessment　framework　based　on　the　structural　performance　index　and　the　vulnerability　curve　for　shallow　tunnels　are　established.　Ac-cording　to　the　findings,　when　the　mass　of　TNT　in　the　tunnel　exceeds　300　kg,　the　tunnel　is　in　danger　of　collapsing.　At　this　moment,　it　is　suggested　that　people　enter　the　tunnel　cautiously.　The　vulnerability　curve　predicts　the　failure　probability　of　a　tunnel　under　various　blast　loads.　At　the　same　time,　it　could　assess　its　structural　perfor-mance　after　the　disaster.