A Case Study on Typhoon Wave-induced Hydrodynamic Behaviors Leading to Seawall Damages with the SPH Method

In this study, a Smoothed Particle Hydrodynamics (SPH) model was applied to simulate the hydrodynamic behaviors of wave overtopping for evaluating typhoon wave-induced damages on seawalls at two sites in Keelung, Taiwan. The instantaneous throw velocity (uz), maximum horizontal throw speed (ux), down-falling composite velocity of overtopping flow (vd), and influenced distance (L) of wave overtopping have been estimated. The simulated overtopping throw speed (uz) over seawalls at both sites are about 2.0 to 3.5 times of the inshore wave celerity at the toe of seawall. Higher seawall and lower waves being inducing the smaller overtopping horizontal throw speeds (ux) could effectively decrease the influenced distance (L) on top of the seawall close to the parapets by down-falling overtopping water while lower seawall and higher waves increase the influenced distance (L). The down-falling waters at both different crests before landing on top of the seawalls have similar velocities so that the overtopping discharges and influenced distances become the primary safety factors for seawall design criteria.