With　the　rapid　development　of　the　tunnels　constructed　under　the　rivers　and　seas　in　China,　the　research　on　face　stability　of　shield　tunnel　in　fault　fracture　zone　with　high　hydraulic　pressure　has　important　theoretical　value　and　engineering　application　significance.　In　this　paper,　considering　the　effect　of　interface　between　intact　rock　mass　and　fault　fracture　zone,　the　existing　wedge-prism　model　is　improved,　and　a　new　limit　equilibrium　prediction　model　considering　geological　interface　is　established.　Based　on　the　limit　equilibrium　theory,　the　expression　of　limit　support　pressure　of　shield　tunnel　surface　is　deduced,　and　the　change　laws　of　limit　support　pressure　and　failure　inclination　angle　in　the　process　of　shield　tunneling　approaching　the　interface　between　intact　rock　mass　and　fault　fracture　zone　are　studied.　The　results　show　that　when　the　shield　tunnel　face　is　far　away　from　the　interface　face　or　has　passed　through　the　interface　face,　the　failure　range　of　the　rock　and　soil　mass　in　front　of　the　tunnel　excavation　is　consistent　with　that　in　the　intact　rock　mass　or　fault　fracture　zone,　and　the　result　of　the　limit　support　pressure　is　consistent　with　the　conventional　existing　wedge-prism　model.　When　the　shield　tunnel　is　excavated　to　the　distance　of　fault　fracture　zone　interface　is　less　than　the　critical　failure　length,　as　the　distance　decreases,　the　limit　support　pressure　increases　rapidly　and　the　maximum　is　about　3.5　times　than　the　value　in　intact　rock　mass.Therefore,　the　support　pressure　of　tunnel　face　should　be　strictly　controlled　at　this　stage　to　avoid　water　gushing　and　mud　sudden　accident.　©　2020,　Editorial　Office　of　China　Civil　Engineering　Journal.　All　right　reserved.