Application of Cell Assembled Double Row Steel Sheet Pile Diversion Cofferdam Technology

With the development of urban rail transit technology, some construction projects involve excavation of foundation pits that cross rivers and streams. In order to protect the excavation of foundation pits from being affected, it is necessary to set up a cofferdam around the foundation pit to prevent river water intrusion. Steel sheet pile cofferdam has become the preferred choice for many water related foundation pit excavations. However, using traditional soil cofferdam or single row steel sheet pile cofferdam for diversion cofferdam construction can easily cause soil erosion and dust pollution in the excavation site during soil collection and transportation, and the stability of the cofferdam is not high. This article is based on the entry and exit line project of Chisha Rolling Stock Depot on Guangzhou Metro Line 11. By analyzing common practices at home and abroad, the construction technology of diversion cofferdams is improved and innovated. The technology of cell assembled double row steel sheet pile diversion cofferdams is developed, and the stability, operability, and environmental protection of the cofferdams are innovated, ultimately forming a set of practical and feasible construction processes. The practical results show that this technology can be used for construction from both sides of the river to the middle at the same time, with a fast construction speed. Compared with the traditional method of erecting piers and driving steel sheet piles, it saves the construction cost of four 36b I-shaped steel piers. In terms of materials, a total of 384000 yuan is saved, and the construction period can be saved by 12 days. It minimizes the pollution of water in the river caused by filling in the cofferdam, optimizes the performance of the cofferdam in terms of wave resistance, impermeability, and other aspects, and can provide reference and experience for other similar projects.