Abstract: In the selection of the suitable supporting systems for the deep excavation supporting for the excavation depth less than seven meters, several rake systems are available. They are: reinforced concrete rakes; steel pipe rakes; rolled steel rakes; or the unclosed raking system from combination of above methods. This paper presents a case history of utilizing an unclosed rake system that from the combination of supporting methods used in various excavation areas in a deep excavation in Shanghai soft soils. Following an introduction of the overall project excavation support information, the application of various rakes, such as, reinforced concrete, steel pipe and rolled steel, as well as their critical design aspects are presented. The vertical face of the excavation could be gravity wall consisting of soilcement mixed columns, soilcement mixed wall (SMW). The paper also presents the predicted deformation in the supporting system using numerical analysis by PLAXIS. The predicted deformation results are comparable to the monitored data.

Key words: Steel Pipe Strut System, Reinforced Concrete Strut System, Unclosed Supporting System, Mucky Soft Soils