This　paper　focuses　on　the　performance　of　a　braced　deep　excavation　in　soft　soil　based　on　field　monitoring　and　numerical　modeling.　Laboratory　tests　were　conducted　to　determine　the　soil　parameters　used　in　the　modified　Cam-Clay　(MCC)　model.　Intelligent　field　monitoring　means　were　adopted　and　a　three-dimensional　model　was　established.　Spatial　and　temporal　effects　induced　by　the　excavation　are　investigated　for　the　deep　-large　foundation　pit　in　soft　soil.　Deformation　characteristics　of　the　enclosure　structure　and　the　surrounding　environment　throughout　the　excavation　process　are　presented.　The　behaviors　of　diaphragm　walls,　columns,　the　maximum　wall　deflection　rate,　ground　surface　settlement,　and　utility　pipelines　were　focused　on　and　investigated　during　the　whole　excavation　process.　Besides,　the　axial　forces　of　the　internal　supports　are　analyzed.　Based　on　the　measured　and　simulated　data,　the　following　main　conclusions　were　obtained:　the　numerical　simulation　results　are　in　good　agreement　with　the　measured　values,　which　proves　the　accuracy　of　the　model　parameters;　the　wall　and　the　ground　surface　showed　the　maximum　displacement　increment　at　stage　9,　which　was　a　coupled　product　of　the　＂creep　effect　＂　of　the　soft　soil　in　Nanjing,　China　and　the　＂depth　effect　＂　of　the　excavation;　as　the　excavation　progressed,　the　ground　settlement　changed　from　a　＂rising　＂　to　a　＂spoon　-shaped　＂　trend,　6　vm　was　measured　between　6　vm　=　0.0686%　H　and　6　vm　=　0.1488%　H　;　the　rebound　deformation　curve　of　the　pit　bottom　was　corrugated,　and　the　depth　of　disturbance　of　the　pit　bottom　after　the　completion　of　soil　unloading　was　2-3　times　the　excavation　depth;　the　closer　the　pipeline　is　to　the　corner　of　the　pit,　the　less　the　excavation　process　will　affect　the　settlement　of　the　pipeline　and　the　less　the　obvious　pit　corner　effect　will　occur;　the　support　strength　of　the　buttress　and　the　longest　corner　brace　should　be　strengthened　during　the　actual　construction　process　to　ensure　the　stability　of　the　foundation　deformation.