Centrifuge modelling of breaking waves and seashore ground

Seashore ground stability is a crucial issue in the composite problems of hydraulics and geotechnics. Many studies have been conducted on covering materials and sediment transport. However, very few studies have examined this issue from a geotechnical viewpoint. This is because the ground displays complicated responses against breaking waves, and because it is difficult to examine ground behaviours through a prototype-scale model test. The physical modelling of breaking wind waves and seashore ground helps explain ground stability. This study examined the efficacy of centrifuge modelling with regard to this issue. The authors showed the similarity laws, including fluid behaviours and developed a new wave generator. The centrifuge model efficacy was verified mainly by way of the modelling of model tests on waveform, wave height and water pressure on and in the ground. Additional tests indicated that excess pore-water pressure was generated due to wave set-up. Increasing the wave height and/or wave frequency caused a seepage force, which could decrease ground stability.