Abstract:The foundation pit of Huajing station in bid 4 of Shanghai airport connecting line is an ultra deep foundation pit, which is divided into four independent areas for excavation, of which the excavation depth of the foundation pit in zone 4 is 42.898m; At present, the biggest construction difficulty in the construction of ultra deep foundation pit is the deformation control of foundation pit retaining structure. With the deepening of the excavation depth of the foundation pit, the excavation conditions also tend to be complex. Once the deformation of the foundation pit is too large, it will lead to the settlement, tear and even damage of the surrounding buildings and underground pipelines, which will bring great risks to the excavation of ultra deep foundation pit. Servo steel support has the advantages of fast installation and immediate support. It can control the deformation of retaining structure in the process of excavation, and is widely used in the process of ultra deep foundation pit excavation; Sliding formwork is a kind of movable molding membrane in concrete structure. The construction progress is fast, which can greatly improve the mechanical efficiency. In the process of foundation pit excavation and construction of the project, the two are organically combined. The application of sliding rapid pre support system in ultra-deep foundation pit construction is studied. The general situation and construction technology of the system are introduced in this paper, By analyzing the deformation control effect of foundation pit retaining structure, combing, summarizing and analyzing its advantages and disadvantages, it provides a reference for the subsequent application of similar ultra deep foundation pit projects.
