Stability analysis of temporary cofferdam of a ship lock construction project in coastal area

The determination of the structural type and location of the cofferdam is the key to the design, and the stability of the cofferdam is the premise to ensure the subsequent construction. Based on the actual project, the stability of the existing cofferdam during the foundation pit dewatering is tested and studied on site, the safety coefficient of the cofferdam is given by using the foundation calculation software of port engineering, and the specific position of the potential slip surface of the foundation is determined, finally, the optimal design and stability analysis of the current cofferdam structure are carried out, the results show that: the cofferdam has the problem of leakage, so the corresponding water isolation measures should be taken, and the foundation pit dewatering causes large horizontal displacement of the foundation, the sliding failure surface occurs in the muddy clay layer; the cofferdam has instability and leakage problems, in order to meet the safety of later construction, the structure of the cofferdam should be optimized; combined with the distribution law of the failure surface of foundation slip, the optimization scheme of driving steel sheet pile in the inner side of cofferdam core soil is put forward; it is verified that the steel sheet pile cofferdam can meet the stability needs of foundation pit during dewatering and after excavation, which is a reasonable and effective support scheme.