Abstract: The supporting cost is a significant portion in the deep excavation and foundation engineering. The conventional deep excavation supporting design is usually conservative in order to reduce the supporting failure during the construction. However, the cost of the supporting is usually not optimized as a result of this conservative design. This paper presents a deep excavation case in the complicated subsurface conditions in Xi'an City. The deformation and stress changes in the supporting system have been numerically predicted and measured. The numerical analyses on the supporting system verified that the design of the system is safe and reliable. Further, the analytical results also confirmed that the parameters used were reasonable.  The supporting system optimization was performed based on the results of numerical analysis; the ground anchor and the dimensions of the secant piles are optimized and the cost was able to be reduced.

Key words: Deep Excavation, Numerical Analyses, Deformation, Design Optimizations, Construction Cost