To　evaluate　hydraulic　head　distribution　in　front　of　a　shield　tunnel　in　a　saturated　soil　layer,　theoretical　analysis　and　numerical　simulations　are　carried　out　in　this　study.　Based　on　the　partial　differential　equilibrium　equation　of　seepage　flow,　a　three-dimensional　(3D)　theoretical　analytical　model　of　the　shield　tunnel　face　and　the　seepage　field　in　front　of　it　is　established　using　the　eigenfunction　and　the　Fourier　series　expansion　methods,　and　the　hydraulic　head　calculation　formula　is　derived.　Combined　with　engineering　cases,　the　theoretical　analysis　results　and　the　3D　numerical　simulation　results　are　compared　and　analyzed.　The　effect　of　the　water　pressure　of　the　tunnel　face　on　the　hydraulic　head　distribution　is　also　analyzed.　The　results　of　the　proposed　analytical　solution　are　in　agreement　with　those　of　the　numerical　simulation　solutions;　moreover,　the　proposed　analytical　solution　requires　less　time　to　calculate　the　seepage　hydraulic　head　than　the　numerical　simulation.　The　ratio　of　the　initial　water　table　to　the　diameter　(D)　of　tunnel　face　has　a　more　significant　impact　on　the　hydraulic　head　distribution　at　a　position　0.5D　above　the　tunnel　vault.　When　the　water　pressure　on　the　tunnel　face　is　not　considered,　the　values　of　the　hydraulic　head　are　significantly　underestimated.　©　2021　Tongji　University