Abstract: The selection and layout of deep excavation support system in soft soil area should be determined by the plan dimensions and shape of the excavated area, the requirements of surrounding environmental protection, the geological conditions of the site and the requirements of the excavation depth. Generally, cast-in-place concrete structure is used as the support of excavation structure with restrictive requirements of surrounding environment or complicate shape for the supporting. Based on the complex shape of the deep excavation project of Zhuguang New City Phase III and the high requirements of the surrounding environment, this paper analyzes the design of the internal support method, introduces the design optimization of the project: from the preliminary reinforced concrete diagonal brace to the reinforced concrete horizontal brace, and further puts forward the optimization of the reinforced concrete horizontal brace to the steel brace, so as to realize the economic and engineering saving It is expected to achieve good results.

Key words: Soft Soil, Deep Excavation Design, Internal Support, Horizontal Support, Steel Strut Support, Raker Support