In　order　to　quantitatively　study　the　influence　of　the　weakening　of　the　disconnectable　coupling　joint　(DC　joint)　on　the　retaining　structure,　the　pre-axial　force　retention　performance　of　the　steel　support,　the　axial　force　of　the　steel　support,　the　horizontal　displacement　of　the　diaphragm　wall,　and　the　ground　settlement　around　the　foundation　pit　were　monitored　during　the　construction　of　the　foundation　pit.　The　evolution　process　of　the　monitoring　data　was　analyzed,　and　the　corresponding　numerical　model　verified　by　the　monitoring　data　was　established.　The　influence　of　the　yield　load　of　the　DC　joint,　the　initial　compression　stiffness,　and　the　weakening　of　the　pre-axial　force　on　the　stability　of　the　retaining　structure　was　studied　by　numerical　simulation.　The　results　show　that　the　pre-axial　force　of　steel　support　is　only　67%　of　the　design　value　when　the　soil　below　is　not　excavated　within　24　h.　The　DC　joint　has　a　significant　weakening　effect　on　the　steel　support,　which　is　unfavorable　for　the　stability　control　of　the　foundation　pit　retaining　structure.　The　pre-axial　force　and　initial　bending　stiffness　have　a　great　influence　on　the　stability　of　the　retaining　structure.　When　the　yield　load　is　not　lower　than　that　of　the　row　piles,　the　DC　joint　has　no　effect　on　the　stability　of　the　retaining　structure.　This　model　can　predict　and　analyze　the　deformation　trend　under　different　working　conditions　to　a　certain　extent,　providing　certain　reference　value　for　safety　plans　during　construction.