The　joint　bending　test　was　carried　out　to　study　the　bending　mechanical　property　and　deformation　characteristics　of　the　F-type　socket　joint　in　rectangular　pipe　jacking　tunnels　under　the　conditions　of　foundation　settlement,　construction　disturbance　and　different　upper　loads.　The　supporting　function　of　soils　under　different　geological　conditions　on　the　rectangular　pipe　jacking　was　simulated　by　arranging　different　numbers　of　equivalent　foundation　springs　at　the　bottom　of　the　pipe.　The　test　results　show　that　the　greater　the　foundation　stiffness　is,　the　greater　the　joint　bending　moment　will　be　at　the　same　loading　displacement,　which　leads　to　greater　joint　opening　deformation.　When　the　pipe　joint　itself　produces　large　deformation,　the　change　rate　of　joint　opening　slows　down,　and　the　slope　of　the　bending　stiffness　curve　of　the　joint　increases.　The　bending　bearing　capacity　of　the　joint　is　closely　related　to　the　foundation　stiffness.　The　greater　the　foundation　stiffness　is,　the　higher　the　bending　bearing　capacity.