To address the sliding problem of the berthing structure in an artificial island with tied-back sheet piles,we build a 3D finite element model using the“Nanshui”double-yield surface elasto-plastic constitutive model.Then we systematically simulate structural responses under various construction loading processes,water level conditions,and service loads,thereby revealing the mechanical mechanism of sliding and proposing corresponding treatment solutions.The results indicate that sliding primarily stems from insufficient bearing capacity of the weak silty clay foundation and an imbalance in lateral earth pressure caused by asynchronous filling and rock dumping during construction.Under the design low water level condition,the peak tensile stress at the southeast retaining wall reaches 1.60 MPa;while this does not exceed the material strength,it poses a potential threat to long-term durability.Moreover,the non-slip dominant factor of the design load has a much smaller increase in the structural response than the influence of filling and water level changes.The proposed remediation measure of supplementary counter-pressure dumping enhances the bearing capacity of soil in the passive zone and lateral constraints,increases the anti-sliding safety factor to 1.050 under extreme low water level conditions,and meets code stability requirements.