Abstract: Selection of a cost effective and safe supporting structure for the deep excavation in soft soils with relatively shallow depth is critical to the foundation cost control. The supporting structure selections of sallow excavation depth in Whenzhou soft soils are evaluated through a case history from aspects of design approach, analysis method, and construction monitoring. The following conclusions can be presented: ⑴Thinwalled cantilever large diameter reinforced concrete cylindrical pile has the advantages of cost effective, short construction period, and good deformation control in the constraint space where the slope, or ground anchor cannot be applied. ⑵It is inappropriate to estimate the total deflection only from formula in the code and the total deflection should consider the daily creep. Further, the allowable total deflection should consider the adjacent environment. ⑶The deeper excavation such as the excavation of elevator shaft, has the obvious adverse effect of the safety of supporting structure. The supporting design of these areas should be specially considered.

Key words: Thick Soft Soils, Supporting Structures for Shallow Excavation Depth, Cylindrical Pile Supporting Structures, Total Deflection