Local　failures　(loss　of　concrete　or　reinforcement)　can　severely　compromise　the　bearing　capacity　of　shield　segments,　damaging　the　tunnel　structures.　To　investigate　the　effects　of　local　openings　on　the　bearing　behavior　and　failure　mechanism,　four　full-scale　bending　tests　were　conducted　on　specimens　with　different　opening　positions　and　diameters;　monitoring　of　load,　displacement,　and　concrete　strain　was　performed　during　loading.　The　test　results　reveal　that　both　the　opening　position　and　diameter　significantly　influence　the　bearing　characteristics　of　the　segment.　The　failure　process　includes　four　sequential　stages　distinguished　by　three　critical　loads,　namely　the　cracking,　failure,　and　ultimate　loads.　Subsequently,　the　numerical　model　of　the　local　failure　segment　was　established　using　the　elastoplastic　damage　constitutive　relation　of　the　concrete　and　verified　by　inversing　the　full-scale　test　results.　Based　on　the　numerical　model,　parametric　analyses　were　performed　to　comprehensively　investigate　the　influences　of　the　opening　position,　concrete　loss,　and　reinforcement　loss　on　the　bending　capacity.　Furthermore,　an　analytical　model　was　proposed,　indicating　that　the　opening　position　is　the　primary　factor　decreasing　the　bearing　capacity,　followed　by　the　opening　diameter　and　reinforcement　loss.　The　results　of　this　study　can　provide　a　theoretical　basis　for　the　safety　assessment　and　remedial　design　of　subway　shield　tunnels　under　extreme　breakthrough　conditions.