Abstract：Research purposes:The bored pile and diaphragm wall are the most commonly used for the enclosure structure for the deep foundation pit，but they need complex technologies and make the mud pollution. In addition，by using them，it is difficult to guarantee the quality of underground concrete and the construction progress is slow with high construction cost. Therefore，the method of using prefabricated steel box pile(SBP ) as supporting of foundation pit is presented in this paper. The research was done on the stiffness and strength of the steel box pile and also on its social and economic benefits，and based on this，its feasibility was discussed.
Research conclusions:(1)The steel box pile enclosure structure can completely meet the requirements of stiffness and strength of foundation pit.(2)The steel box pile enclosure structure can be widely used in coastal soft soil area and river terrace zones.(3)The piling and pile pulling can be done by using existing equipment(4)When using the steel box pile enclosure structure，it is unnecessary to drill hole or dig trench，so there is no mud pollution.(5)By simplifying the design and construction work，the construction progress can be speeded up.(6)The steel box pile can be used repeatedly，therefore，the resources and the cost can be reduced.(7)It can be widely used，so the good social and economic benefits can be obtained.
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2012, Vol. 29 
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