Abstract: The deep excavation of an underground parking lot at Wujin Station (namely Wujin Project), a comprehensive transportation hub which is an inter-city station of the south express railway alongside Yangtze River. The construction is a super-large one with footprint area of about 39,500 square meters, with an excavation depth of 11.2 meters and periphery of about 980 meters. The excavation is supported by the double-row cantilever piles (DCP) using sequential method (SM). The principle of the SM is based on the Space-time Effect theory. For a deep excavation project, it is very important to select a reasonable length of sequential block to control the displacement of the retaining wall. To minimize the displacement of the double-row-piles retaining wall, a sequential method is introduced for the excavation of Wujin Project, for which a calculation model is established to analysis cases with different length of sequential block with consideration of Wujin Project’s retaining wall and geological conditions. The result shows that there is a critical length (CL) and that when the length of sequential block is less than CL, the displacement of the retaining wall is very sensitive to the length of sequential, otherwise is irrelevant to it.

Key words: Sequential Method of Excavation, Double-Row-Piles Retaining Wall, Deep Excavation, Cantilever Retaining Wall