Abstract: The design and construction deep excavation supporting structure is a complex and comprehensive geotechnical engineering problem, the supporting structure design options and the final implementation are affected by many factors. The case history of a deep excavation in soft soils of Junlong Automobile Industrial Park project in Panyu District, Guangzhou is presented in this paper. The key aspects and difficulties in the deep excavation of this project are summarized. The selection of supporting design options in combination with the surrounding environment of the excavation, the excavation depth and the geotechnical conditions of the rock and soil strata, and the final design selection of the excavation support was determined as follows: sloping the side excavation, the use of cement mixed columns with insertion of steel sheet piles, steel pipe internal support, and reinforcement of the passive zone within the excavation. The measured displacements in the construction process are monitored and analyzed. The results prove that the deep excavation can be constructed safely and effectively, which can provide a valuable reference for the design and construction of the same type of soldier pile supporting structures.

Key words: Deep Excavation Engineering, Soft Soils, Steel Sheet Pile, Soldier Pile Support, Monitoring