Abstract: The foundation pit of Huai'an International Square located in the city center is a super-large and deep excavation project. The requirement for protection of its adjacent surroundings is quite strict. The silt soil with a great deal of water is widely distributed in this excavation. In order to ensure the waterproof effect of the excavation and a protect the surrounding environment, the TRD wall is firstly used in Jiangsu areas, which is a new retaining structure for excavation, or named the constant thickness cement-soil wall constructed by the TRD method. It is successfully used to cut off groundwater and to ensure the safety of the surrounding environment in the project. Based on the deep excavation project of Huai'an International Square, the characteristics,application conditions and key design technology of the new excavation retaining structure “TRD” are introduced.