Physical model tests for the hydrodynamics of traditional seawalls and mild-slope seawalls
張 憲 國
|關鍵字:||傳統海堤;緩坡海堤;反射率;溯升;越波;traditional seawall;mildly sloping seawal;reflection;runup;overtopping|
The wave reflection, runup, and overtopping on a traditional seawall and on a mildly sloping seawall were examined by physical model tests. The results proved that the mildly sloping seawall has less wave reflection, runup and overtopping than the traditional seawall. Both wave reflection and runup on a seawall decrease as the incident wave steepness increases, but are proportional to the surf parameter. Wave breaking has a strong effect on wave overtopping. The position of wave breaking is far from the toe of a seawall when the incident wave steepness is large. Therefore, wave overtopping decreases when wave breaks at far distance from the toe of a seawall. The experimental results showed that the wave overtopping is proportional to the relative freeboard, which is defined a ratio of the freeboard to wave height, when its value is less than 0.85, and that wave overtopping decreases as the relative freeboard increases when its value is larger than 0.85. We also found that the wave overtopping is quadratically proportional to the relative freeboard.