Design of Retaining and Protecting for a Deep Foundation Excavation

Abstract

Urban development often requires the construction of deep excavations. There are some difficulties during design and construction of foundation excavation, such as large engineering quantity, poor geological conditions, as well as challenges to design and construction of retaining and protecting structure. To solve these difficulties, supporting system of steel circle beam, steel pipe support and stiffened support compounding with steel pipe pile cofferdam is designed. Soil resistance calculating method is used for support structure design in all possible conditions and the result is compared with that using the classical method. With reasonable supporting process and construction measures, monitoring results including displacement of steel pipe piles and greatest axial force can meet the norm requirements. It is proved that the retaining and protecting system designed is safe and reliable. With the benefit of small deformation and high integrity, locking steel pipe piles gave full play to its locking function of water. The design method in the paper is feasible and may offer some references for similar deep foundation excavation.