臺灣博碩士論文加值系統

本研究探討海床土壤性質差異對波浪引致淘刷之影響，將土體相對密度性質納入海床淘刷行為作為考量項目，以渥太華無凝聚性標準砂鋪設成試驗海床，並透過改變不同土體相對密度方式配合三種粒徑條件，分析不同相對密度土體對於淘刷所需起動剪應力值之影響。並將試驗結果進行薛爾茲參數轉換，計算成不同波浪條件下臨界起動之無因次剪應力，並與Shields (1936)所作之薛爾茲曲線進行比較。
本研究試驗結果顯示，各粒徑條件下，高相對密度土體所需起動之臨界底床剪應力皆比低相對密度土體為高，即高相對密度土體在抗波浪淘蝕能力上表現較低相對密度土體好；在薛爾茲參數轉換方面，透過試驗結果得知在同一粒徑條件下之土體會因相對密度不同而在薛爾茲曲線上顯現不同之抗淘蝕剪應力。若以莫爾庫倫破壞準則計算土壤抗剪力，計算得出之淘刷深度會遠小於實際淘刷深度，顯示海床受流體運動引致淘刷可能不僅受流體引致底床剪力作用破壞，若僅考慮流體引致底床剪力破壞進行波浪造成海床淘刷深度計算時，可能會低估淘刷深度。

This thesis takes the relative density of the soil properties into account and studies on the effect of scouring. Through the way of experiment, this thesis firstly changes the different relative density to analysis the initial motion effect of three kinds of particle conditions. Then, take the experimental results into converting to the shields parameters for discussing that how much shear stress is required to start into initial motion. After that, compare with the original shields curves by Shields. Finally, use the Mohr Coulomb failure criteria to analysis the seabed particles that how to get into initial motion by shear stress acts and understanding which mechanisms of scouring due to wave.
The results of experiment showed that under the conditions of the particle size for different relative densities, the high relative density soil that needed critical shear stress is higher than the low relative density soil. Namely, it means that the high relative density soil in the ability to resist scouring is better than the low relative density soil due to wave. On the converted of shields curves, the results of experiment appears that the same particle size shows different ranges due to different relative densities. Afterwards taking the result into mechanical analysis found that the theoretical calculated value is much less than the actual scouring value. Based on the results above, inferring the seabed scouring caused by the fluid may not only suffers from the shear stress but also has contained more complex mechanisms. Therefore, if users simply take the shear stress to research the initial motion of sediment and calculate the scouring depth, there will perhaps come out inaccuracies.

摘要 I
Abstract II
誌謝 III
目錄 V
表目錄 VII
圖目錄 VIII
符號表 X
第一章 緒論 1
1-1 研究動機 1
1-2 研究目的 2
1-3 試驗流程 3
第二章 文獻回顧 4
2-1 泥砂起動定義 4
2-2 底床剪應力 6
2-2-1 波浪引致之底床剪應力 6
2-2-2 水流引致之底床剪應力 10
2-2-3 水流及波浪混合條件之底床剪應力 11
2-3 土壤之抗剪強度 12
2-3-1 莫爾庫倫破壞準則 12
2-4 薛爾茲曲線之討論 15
2-4-1 薛爾茲曲線 15
2-4-2 波浪作用下之薛爾茲曲線 18
2-4-3 無因次化粒徑參數與無因次化剪應力參數之推估 22
第三章 室內試驗與試驗方法 23
3-1 室內試驗 23
3-1-1 試驗設備 23
3-1-2 試驗模型 27
3-1-3 試驗配置 32
3-2 試驗方法 33
3-2-1 底床砂土材料相對密度試驗 33
3-2-2 材料剪力強度試驗 36
3-2-3 波浪底床剪應力試驗 38
第四章 試驗結果分析與討論 40
4-1 不同粒徑之波浪臨界剪應力分析結果 41
4-2 波浪作用力下之薛爾茲曲線 45
4-3 底床抗剪強度與其激發摩擦角 48
第五章 結論與建議 53
5-1 結論 53
5-2 建議 54
參考文獻 55

1.Bagnold, R. A. (1946). “Motion of Waves in Shallow Water - Interaction between Waves and Sand Bottoms, Proceedings of the Royal Society of London Series a-Mathematical and Physical Sciences, Vol.187, pp. 1-18.
2.Bagnold, R. A. (1963). “Mechanics of marine sedimentation, The Sea: Ideas and Observations, Vol. 3, pp. 507-28.
3.Bruce, D. (1969). “Relative density effects on incipient bed movement, Water resouces research, Vol. 5, NO.5.
4.Braja, M. DAS. (2006). Principles of Geotechnical Engineering, Cengage Learning, USA.
5.Cubrinovski, M., and Ishihara, K. (2002). “maximum and minimum void ratio characteristics of sands, Soils and foundations, Vol. 42, NO. 6, pp.65-78.
6.Dingler, j. R. (1974). “wave-formed ripples in nearshore sands, Part II: Coastal Sediment Problems, Scripps Institution of Oceanography, United States, pp. 2109-2126.
7.Engelund, F., and Fredsøe, J. (1976). “A sediment transport model for straight alluvial channels, Nordic hydrology, Vol. 7, pp.293-306.
8.Fredsøe, J., and Deigaard, R. (1992). Mechanics of Coastal Sediment Transport, World Scientific Publishing, Advanced Series on ocean Engineering, Vol. 3.
9.Komar, P. D., and Miller, M .C. (1974). “Sediment threshold under oscillatory water waves, J. Sediment. Petrol, Vol. 43, pp. 1101-1110.
10.Nielsen, P. (1992). Coastal bottom boundary layers and sediment transport, World Scientific, London.
11.Shields, A. (1936). Anwendung der Ahnlichkeits-Mechanik und der Turbulenz-forschung auf die Geschiebebewegung, Preussische Versuchsanstalt fur Wasserbau und Schiffbau, Vol. 26, Berlin.
12.Sumer, B. M., and Fredsøe, J. (2002). The mechanics of scour in the marine environment, World Scientific, London.
13.Soulsby, R. L. (1995). “Bed shear-stresses due to combined waves and currents, Advances in Coastal Morph dynamics, Delft Hydraulics, Netherlands, pp.420 - 423.
14.Gotschol, A. (2002). Veränderlich elastisches und plastisches Verhalten nichtbindiger Böden und Schotter unter zyklisch-dynamischer Beabspruchung, Dr-ing, Fachgebiet Geotechnik, University of Kassel, Kassel.
15.Kluge, K. (2007). Soil Liquefaction around Offshore Pile Foundations-Scale Model Investigations, Dr.-Ing, Faculty of Engineering, University of Florence, Germany.
16.Singh, H. (2009). Scour around Vertical Piles under the action of Waves and Currents, M. Sc., University of Kiel, Germany.
17.Soulsby, R. L. (1997). Dynamics of marine sands, Thomas Telford, New York.
18.Soulsby, R. L., and Whitehouse, R. J. S. W. (1997). “Threshold of sediment motion in coastal environments, Proc. Pacific Coasts and Ports ’97 conf, Christchurch, Vol. 1, pp. 149-154. University of Canterbury, New Zealand.
19.Van Rijn, L. C. (1993). Principles of Sediment Transport in Rivers, Estuaries and Coastal seas, Aqua Publications, Amsterdam.
20.Whitehouse, R. J. S. (1995). “Scour at marine structures. A manual for practical applications, Report SR417, HR Wallingford.
21.Yalin, M. S. (1997). Mechanics of sediment Transport, 2nd edn, Pergamon press, Oxford.
22.伍恆志(2012)，「天然壩材料粒徑對壩體溢流破壞之影響」，國立成功大學水利及海洋工程研究所碩士論文。
23.施國欽(2005)，大地工程學（一）土壤力學篇，文笙書局。
24.紀智成(2012)，「應用PIV探討波浪作用下底質始動條件」，國立成功大學水利及海洋工程研究所碩士論文。
25.許泰文(2003)，近岸水動力學，中國土木水利工程學會。
26.許泰文(2007)，海岸漂砂對海岸地形變遷的影響，財團法人中興工程科技研究發展基金會。
27.郭一羽(2003)，海洋工程學，文山書局。
28.郭金棟(1995)，海岸工程(第二版)，中國土木水利工程學會。
29.黃冠勳(2012)，「沖刷帶內底床剪應力之研究」，國立成功大學水利及海洋工程研究所碩士論文。
30.錢寧(1991)，泥沙運動力學，科學出版社。