本試驗利用斷面造波水槽，探討非線性波浪作用於細顆粒砂質海床(d50=0.073mm)上引致液化反應時，水面波浪與底床反應間交互作用結果。從結果發現，液化時相對水深對波浪能量減衰程度、孔隙水壓的消散和共振放大的比例及海床面振動的大小方面，都是一個重要的影響關鍵。當波浪作用的動壓越大則液化深度也會越深；而當液化深度越深時，海床的振動幅度也跟著放大。在此時海床面的振動與波浪的主頻一致，進而推論海床面振動是由波浪強制引致而成的振動情形。至於懸浮漂砂可能因近底床的流速運動型態的改變及海床面的振動所造成，且其週期性現象也與海床面振動及波浪作用有關。
從頻譜圖來看，非線性影響不只出現在表面的波浪上，也會影響到液化後底床的反應量，如孔隙水壓力振幅、海床面振動和水平及垂直流速等。即使因液化發生而在波浪能量上有發生衰減，但衰減卻只有發生在主頻上，所以高倍頻的能量影響依然存在，其中尤以近底床處的流速受非線性影響較為顯著，這應為波浪與海床的交互作用，而使近底床處的反應更為複雜。
本試驗也整理匯合前人資料，對底床在不同的顆粒大小下，求出發生共振式液化的條件(相對水深、波浪尖銳度)趨勢線，本趨勢線可用來推估液化可能發生的波浪條件。本試驗也利用這些資料進而深入探討共振式液化時所產生的底床反應(液化深度、海床振動)之相關機制。

In this study, the interactions of nonlinear waves and a wave-fluidized fine sandy bed (d50=0.073mm) are investigated by flume experiments. Experimental results illustrate that relative water depth in a fluidized response is very important to wave decay, pore pressure dissipation, resonance amplification and bed displacement. With larger wave-induced pore pressure oscillations, the resultant fluidized-layer depth becomes deeper and causes increasing amplitudes of bed’s oscillating displacements. In particular, the same peak frequencies of bed’s displacement as those of the loading waves suggest the forced motions of the fluidized bed by surface waves. Accompanying the bed’s displacements in a fluidized response, near-bed fluid velocity fields are noted to be evidently changed while suspended sediment concentrations are significantly increased. In addition, the longer cycles of sediment concentration seems to be related with both bed and wave motions.
According to frequency spectrum, nonlinear effects appear not only on surface waves, but also on bed’s fluidized responses including pore pressure oscillation, bed displacement, and the fluid velocity fields. Even if waves occur to decay, the decay rate is mainly on the peak frequency while the super-harmonic components remain evident in the near-bed fluid velocity fields. This further complicates the interactions of waves and a fluidized bed.
In the end, wave data from former studies with different bed’s particle diameter have been collected to determine the regress lines (relative water depth, wave steepness) for generating resonant fluidization. These regress lines could perform quite well for estimating the wave conditions for a fluidized response so that the mechanism of fluidized layers and bed displacements in a resonant response could be studied in more detail.

1. Barends, F. B. J., and Spierenburg, S. E. J. (1991). "Interaction between ocean waves and seabed." Proceedings of the International Conference on Geotechnical Engineering for Coastal Development –Theory and Practice on Soft Ground (Geot-Coastal’91), Yokohama, Japan, 1091-1108.
2. Bjerrum, J. (1973). "Geotechnical problem involved in foundations of structures in the North Sea." Geotechnique, 23(3), 319-358.
3. Christie, M. C., Dyer, K. R., and Turner, P. (1999). "Sediment flux and bed level measurements from a macro-tidal mudflat." Estuarine, Coastal and Shelf Science, 49, 667-688.
4. Clukey, E. C., Kulhawy, F. H., and Liu, P. L.-F. (1983). "Laboratory and field investigation of wave-sediment interaction." 83-1, Joseph H. DeFrees Hydraulics Laboratory, School of Civil and Environmental Eng., Cornell University, Ithaca, New York.
5. Dean, R. G., and Dalrymple, R. A. (1991). Water wave mechanics for engineers and scientists, World Scientific.
6. Dyer, K. R., Christie, M. C., Feates, N., Fennessy, M. J., Pejrup, M., and Van Der Lee, W. (2000). "An investigation into processes influencing the morphodynamics of an intertidal mudflat, the Dollard estuary, The Netherlands." Estuarine, Coastal and Shelf Science, 50, 607-625.
7. Foda, M. A. and S. Y. Tzang (1994). "Resonant fluidization of silty soil by water waves. " Journal of Geophysical Research, 99 (C10), 20463-20475.
8. Foda, M. A., D. F. Hill, P. L. Deneale and C. H. Huang (1997). "Fluidization response of sediment bed to rapidly falling water surface. " Journal of Waterway, Port, Coastal, and Ocean Engineering, 123 (5), 261-265
9. Huang, C. M. (1996). "A fluidization model for cross-shore sediment transport," Ph. D. Dissertation, University of California, Berkeley, U.S.A.
10. Jansen–Stelder, B. (2000). "The effect of different hydrodynamic conditions on the morphodynamics of a tidal mudflat in the Dutch Wadden Sea." Continental Shelf Research, 20, 1461–1478.
11. Jeng, D.-S., and Lin, Y. S. (1997). "Non-linear wave-induced response of porous seabed: a finite element analysis." International Journal for Numerical and Analytical Methods in Geomechanics, 21(1), 15-42.
12. Jeng, D. S. (2001). "Mechanism of the wave-induced seabed instability in the vicinity of a breakwater: a review." Ocean Engineering, 28, 537-570.
13. Lin, M., and Li, J. C. (2001). "Effects of surface waves and marine soil parameters on seabed stability." Applied Mathematics and Mechanics, 22(8), 904-916.
14. Madsen, O. S. (1971). "On the generation of long waves." Journal of Geophysical Research, 76, 8672-8683.
15. Madsen, O. S. (1978). "Wave-induced pore pressure sand effective stresses in a porous bed." Geotechnique, 28(4), 377-393.
16. Mei, C. C., and Foda, M. A. (1981). "Wave-induced stresses around a pipe laid on a poro-elastic sea bed." Geotechnique 31, 509-517.
17. Pritchard, D., and Hogg, A. J. (2003). "On fine sediment transport by long waves in the swash zone of a plane beach." Journal of Fluid Mechanics, 493(1), 255-275.
18. Sassa, S., and Sekiguchi, H. (1999). "Wave-induced liquefaction of beds of sand in a centrifuge." Geotechnique, 49(5), 621-638.
19. Tzang, S. Y. (1992). "Water wave-induced soil fluidization in a cohesionless seabed," Ph. D. Dissertation, University of California, Berkeley, U. S. A.
20. Tzang, S. Y. (1998). "Unfluidized soil response of a silty seabed to monochromatic waves." Coastal Engineering, 35, 283-301.
21. Tzang, S.-Y., and Ou, S.-H. (2006). "Laboratory flume studies on monochromatic wave-fine sandy bed interactions: Part 1. Soil fluidization." Coastal Engineering, 53(11), 965-982.
22. Whitehouse, R. J. S., and Mitchener, H. J. (1998). Observations of the morphodynamic behaviour of an intertidal mudflat at different time scales, Geological Society London.
23. Yamamoto, T., Koning, H. L., Sellmejjer, H., and Hijum, H. L. (1978). "On the response of a poro-elasticbed to water waves." Journal of Fluid Mechanics, 87, 193-206.
24. Zen, K., and Yamazaki, H. (1990). "Mechanism of wave-induced liquefaction and densification in seabed." Soils and Foundations, 30, 90-104.
25. 蘇美光 (1999)，「規則波引致之細顆粒砂質海床反應特性試驗研究」，國立成功大學水利及海洋工程學系碩士論文。
26. 彭雯章 (2000)，「波浪作用下細砂質海床土壤液化反應與懸浮漂砂濃度特性試驗研究」，國立成功大學水利及海洋工程學系碩士論文。
27. 簡德深 (2001)，「簡諧波與線性波群引致之細砂質海床液化與懸浮漂砂試驗研究」，國立成功大學水利及海洋工程學系碩士論文。
28. 賴宏祐 (2002)，「淺水之規則波與波群引之細砂質海床液化與懸浮漂砂試驗研究」，國立成功大學水利及海洋工程學系碩士論文。
29. 陳勇隆 (2003)，「近液化底床波浪引致之懸浮漂砂傳輸特性初步研究」，國立成功大學水利及海洋工程學系碩士論文。
30. 臧效義， 歐善惠，楊昀哲，鄭肇宗 (2004)，「規則波引致之液化細砂質海床面運動試驗探討」，第二十六屆海洋工程研討會論文集，第654-660頁。
31. 楊昀哲 (2004)，「規則波引致單一矩形潛體前之液化細砂質海床行為試驗探討」，國立成功大學水利及海洋工程學系碩士論文。
32. 王忠濤，染茂田，劉占閣，王棟 (2005)，「淺水區波浪非線性效應對砂質海床動力回應的影響」，海洋工程，第23卷，第1期，第41-46頁。
33. 鄭肇宗 (2005)，「規則波與細砂質海床上透水潛體交互作用之試驗研究」，國立成功大學水利及海洋工程學系碩士論文。