Abstract: The deep excavation site for a City Square in Wuhan is located in the first physiographical terrace of Yangtze River. The characteristics of this project are large excavation depth; irregular in planview; restrictive adjacent environment; containing soft soils and complicated hydrological conditions. The design principals are focused on the safe, reliable, economical, ease to construct, and reasonable construction schedule. The excavation support design combine the unloading by soil removal, soldier piles and internal supports. The dewater techniques are seepage cut-off wall combined with well point dewatering device. During the excavation, the soil and sand piping at the excavated faces were properly treated. All these techniques ensured safe excavation and minimize the impact on the adjacent environment. The excavation monitoring results indicates that all of the monitored items are met the code and design requirements.

Key words: Deep Excavations, Supporting Structures, Design and Construction, Groundwater Control