Abstract: The Yangtze River Navigation Administration Center Project is located at the intersection of Yuanjiang Boulevard and Minsheng Road in Jiangan District. The proposed building has a total area of 46,000 m2 with a building area of 31,500 m2. The foundation excavation area is 38,600 m2, with a perimeter f 888 meters. The proposed excavation depth varies from 10.7 to 21.9 meters and this type of deep excavation can be classified as superlarge excavation project. Based on the hydrological and geological conditions at site, the conventional castinplace reinforced concrete pile with threeaxis cement mixing curtain as a seepage cutoff wall was used as supporting system in areas with twostory underground spaces. In areas with threestory underground spaces, the hydraulic pressure is high due to the required excavation depth. The slurry walls formed by the Trench Cutting Remixing Deep Wall (TRD method was used. The TRD walls can have a large structural depth and is applicable in a wide variety of subsurface conditions. The cross strut supports with corner supports using truss system in the horizontal direction are used in both areas.

Key words: Deep Excavations, Horizontal Supports, Slurry Walls, Trench Cutting Remixing Deep Wall Method