Development of an Empirical Formula for Wave Overtopping of a Single-Chamber Slit Caisson Based on Hydraulic Model Tests

This study proposes a new empirical formula for predicting wave-overtopping discharge for slit caisson structures, which are frequently used in breakwaters and berthing facilities in Korean ports. A total of 429 hydraulic model experiments were conducted under various conditions, including incident wave height, freeboard, water depth, and wave period, to establish a dataset of dimensionless overtopping discharges. Comparison with existing empirical formulas revealed a tendency to overestimate overtopping under certain conditions. A new empirical formula based on an exponential function of the dimensionless freeboard was developed, with its parameters optimized using the Levenberg-Marquardt algorithm. The proposed empirical formula demonstrated improved predictive performance with a low mean error and encompassed the majority of the data within a 90% confidence interval, thus outperforming existing formulas. The results of this study are expected to provide valuable fundamental data for the design and maintenance strategies of slit caisson structures, particularly under future scenarios involving sea level rise and increased frequency of extreme waves.