Abstract: The change of the water level during the construction of the steel sheet pile cofferdam will directly affect the safety of the cofferdam structure. At present, the research on steel sheet pile cofferdam mainly adopts the method of working condition analysis, which will ignore the influence caused by the change of external water level. This study utilizes the subsurface conditions and construction configuration of the Wuhan Xinhe Bridge Project, combined with the PSOSVM water level prediction model. The mode considers the predicted water level as the external change load of the steel sheet pile cofferdam and establishes the ABAQUS threedimensional finite element model under the dynamic load. This study proposes an analysis method that is more in line with the actual construction of steel sheet pile cofferdams. The following conclusions are observed: (1) With the increase of the excavation depth, the displacement of the bottom is larger. Because the existence of the castinplace pile limits the displacement of the bottom, the displacement curve presents two peaks, and the shape of the displacement curve in each analysis step is basically similar. (2) During the entire process of the cofferdam construction, the maximum horizontal displacement at the midpoint of the long side (28.54 mm) is significantly larger than the maximum displacement at the midpoint of the short side (13.88 mm). Therefore, the horizontal displacement at the midpoint of the long side should be monitored more heavily during construction.

Key words: Dynamic Water Load, ABAQUS, Steel Sheet Pile Cofferdam, Displacement Analysis