Starting from the conservation of resources and protection of the urban environment，the development of underground space should avoid large-scale demolition and reconstruction. Therefore，the research of additional basement constructed of the urban center has great significance under the premise of retaining existing buildings. The excavation beneath the existing building will result in changes of the stresses at the pile-soil surface and reduce the bearing capacity of piles. With a case of constructing additional underground parking garage below the existing high-rise buildings on soft soil foundation，expounding the technical difficulties and the key technologies of operation processes，typical operating conditions，designing of vertical supporting structure，underpinning design of additional vertical member(wall，column) in constructing additional building basement with top-down excavation below the existing building. Furthermore，a new control technology for differential deformation of vertical members was proposed.The research results can provide references for the additional basementbeneath existing high-rise building in soft soil.
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2018, Vol. 37 
