台灣地震頻仍，土壤液化幾乎無法避免發生。土壤液化使得土壤強度降低，造成支撐結構物能力下降，進而影響結構物壽命。本論文以有限元素法分析土壤在受到地震力作用後之行為，該有限元素程式係使用流固耦合系統理論做為控制方程式，以Newmark法求解方程式，再以Direct α-method以避免方程式解之震盪；在土壤之非線性行為的部分，採用帽蓋模型模擬。本文使用規範所建議之設計載重案例，包含風、浪、颱風以及不同強度的地震。本文提出了四種方式折減液化後的土壤勁度，並比較此四種方式對於離岸風機總用鋼量之差異、各桿件尺寸之大小和離岸風機之側位移，以驗證土壤液化對於結構物之影響。電腦輔助分析程式由 朱聖浩教授研究團隊所開發，分析程式與研究成果皆為公開資源。

Taiwan is located at the Circum-Pacific seismic belt, so the soil liquefaction caused by the frequent earthquakes is almost inevitable. The soil liquefaction reduces the strength of the soil, resulting in a decline in the ability of supporting structures, which in turn affects the life of the structures. In this thesis, the finite element method is used to analyze the behavior of the soil after being subjected to seismic loads. The coupled soil skeleton and pore fluid interaction is used as the governing equation in the FEM (finite element method) program; the Newmark method is used to solve the equation; the Direct α-method is used to avoid the solution oscillation; the non-linear behavior of the soil is simulated by the cap model. The controlled load cases include winds, waves, typhoon and earthquakes of different GPA which often occur in Taiwan. This thesis proposes four methods to reduce the stiffness of the soil after liquefaction and compares the differences in the total steel amount of the OWTs, the size of the members and the lateral displacements of the OWTs for the four methods, and the comparison result verifies the influence of soil liquefaction on the structure. Note that the computer programs developed by the research team of Shen-Haw Ju are open and free to use.

Akiyoshi, T., Fang, H.L., Fuchida, K. and Matsumoto, H., (1996). A non-linear seismic response analysis method for saturated soil-structure system with absorbing boundary. International Journal for numerical and analytical methods in geomechanics, 20, 307-329.
Alyami, M., Rouainia, M., Wilkinson, S.M., (2009). Numerical analysis of deformation behaviour of quay walls under earthquake loading. Soil Dynamics and Earthquake Engineering, 29, 525– 536.
An, J., Tuan, C.Y., ASCE, F., Cheeseman, B.A., Gazonas, G.A., (2011). Simulation of soil behavior under blast loading. International Journal of geomechanics, 11, 323-334.
Bisoi, S., Haldar, S., (2014). Dynamic analysis of offshore wind turbine in clay considering soil-monopile-tower interaction. Soil Dynamics and Earthquake Engineering, 63, 19-35.
ChengZ, h., Jeremic, B., (2009). Numerical modeling and simulation of pile in liquefiable soil. Soil Dynamics and Earthquake Engineering, 29, 1405-1416.
Chu, H.S., Brandt, H., (1987). International Journal for numerical and analytical methods in geomechanics, 11, 193-202.
Dolarevic, S., Ibrahimbegovic, A., (2007). A modified three-surface elasto-plastic cap model and its numerical implementation. Computers and Structures, 85, 419-430.
Duan, Q., Mao, H., Huang, Z., Li, X., Mao, H., Tang, W., (2019). Sensitivity of important parameters in a three‐dimensional simulation of the milling process of sugar cane with modified Drucker–Prager Cap model based on evolutionary material properties. Wiley Periodicals, 10, 1111.
Dunn, S.L., Vun P.L., Chan A.H.C., and Damgaard J.S., (2006). Numerical modeling of wave-induced liquefaction around pipelines. ASCE, 132:4(276).
Esfeh, P.K., Kaynia A.M., (2019). Numerical modeling of liquefaction and its impact on anchor piles for floating offshore structures. Soil Dynamics and Earthquake Engineering, 127, 105839.
Esfeh, P.K., Kaynia A.M., (2020). Earthquake response of monopiles and caissons for Offshore Wind Turbines founded in liquefiable soil. Soil Dynamics and Earthquake. Engineering, 136, 106213.
Fedock, J.J. (1978). Application of a soil cap model to ground motion analyses. University of New Maxico.
Gamnitzer, P., Hofstetter G., (2013). A cap model for soils featuring a smooth transition from partially to fully saturated state. PAMM, 13, 169-170.
Guy, N., Colombo, D., Frey, J., Cornu, T., Cacas‑Stentz, M.C., (2019). Coupled modeling of sedimentary basin and geomechanics: a modified Drucker-Prager cap model to describe rock compaction in tectonic context. Rock Mechanics and Rock Engineering, 52, 3627-3643.
Han, L.H., Elliott, J.A., Bentham, A.C, Mills, A., Amidon, G.E., Hancock, B.C. Journal of renewable and sustainable energy, 45, 3088-3106.
Huang, Y., Han, Xu., (2020). Features of earthquake-induced seabed liquefaction and mitigation strategies of novel marine structures. Journal of Marine Science and Engineering, 8, 310.
Johari, A., Pour, J.R., (2015). Reliability analysis of static liquefaction of loose sand using the random finite element method. EC, 32, 7.
Ju S.H., Huang Y.C., (2019). Analyses of offshore wind turbine structures with soil-structure interaction under earthquakes. Ocean Engineering, 187, 106190.
Ju S.H., Wang, Y.M., (2001). Time-dependent absorbing boundary conditions
for elastic wave propagation. International Journal for numerical and analytical methods in geomechanics, 50, 2159-2174.
Khoei, A.R., Azami, A.R., Haeri, S.M., (2004). Implementation of plasticity based models in dynamic analysis of earth and rockfill dams: A comparison of Pastor-Zienkiewicz and cap models. Computers and Structures, 31, 5, 385-410.
Khosrojerdi, M., Pak, A., (2015). Numerical investigation on the behavior of the gravity waterfront structures under earthquake loading. Ocean Engineering, 106, 152–160.
Kohler, R., Hofstetter, G., (2007). A cap model for partially saturated soils. International Journal for numerical and analytical methods in geomechanics, 32, 981–1004.
Ku, C., Chien, L., (2016). Modeling of load bearing characteristics of jacket foundation piles for offshore wind turbines in Taiwan. Energies, 9, 625.
Lin, Z., Pokrajac, D., Guo Y., Jeng D., Tang, T., Rey, N. and Zheng J., (2017). Investigation of nonlinear wave-induced seabed response around mono-pile foundation. Coastal Engineering, 121,197-211.
Ling, H.I., Sun L., Liu H., Mohri Y. and Kawabata T. (2008). Finite element analysis of pipe buried in saturated soil deposit subject to earthquake loading. Journal of Earthquake and Tsunami, 2, 1-17.
Lombardi, D., Bhattacharya, S., Scarpa, F. and Bianchi, M., (2015). Soil Dynamics and Earthquake Engineering, 69, 46-56.
Maheshwari, B.K., ASCE, M., Sarkar, R., (2011). Seismic behavior of soil-pile-structure interaction in liquefiable soils: parametric study. International Journal for numerical and analytical methods in geomechanics, 11, 4, 335-347.
McCarron, W., Chen, W. F., (2016). Canadian Geotechnical Journal, 24.
Menezes J.E.T., Fernandes M.M., (1991). The Influence of water on the seismic response of waterfront retaining walls. Computers and Structures, 44, 4, 859-862.
Mizuno, E., Chen, W. F., (1983) Cap models for clay strata to footing loads. Computers and Structures, 17, 4, 511-528.
Oka, F., Yashima A., Shibata T., Kato M. and Uzuoka R., (1994). FEM-FDM coupled liquefaction analysis of a porous soil using an elasto-plastic model. Applied Scientific Research, 52, 209-245.
Pacheco, M.P., Altschaeffl, A.G. and Chameau, J.L., (1989). Pore Pressure Predictions in finite element analysis. International Journal for numerical and analytical methods in geomechanics, 13, 477-491.
Sandler, I.S., DiMaggio, F.L. and Baladi, G.Y., (1974). A Generalized cap model for geological materials. National Technical Information Service U.S. Department of Comimerce.
Sandler, I.S., Rubin, D., (1979). An algorithm and a modular subroutine for the cap model. International Journal for Numerical and Analytical Methods in Geomechanics, 3, 173-186.
Schwer, L.E., Murray, Y.D., (1994). A three-invariant smooth cap model with mixed hardening. International Journal for numerical and analytical methods in geomechanics, 18, 657-688.
Shi, W., Park, H.C., Chung C.W., Shin, H.K., Kim, S.H., Lee, S.S. and Kim, C.W., (2015). Soil-structure interaction on the response of jacket-type offshore wind turbine. International journal of precision engineering and manufacturing-green technology, 2, 2, 139-148.
Simo, J.C., Ju, J.W., (1987). Strain and stress-based continuum damage model-I. formulation. Solid Structures, 23, 7, 821-840.
Tamate, S., Towhata, I., (1999). Numerical simulation of ground flow caused by seismic liquefaction. Soil Dynamics and Earthquake Engineering, 18, 473-485.
Tong, X., Tuan, C.Y., (2007). Viscoplastic cap model for soils under high strain rate loading. Journal of renewable and sustainable energy. Journal of renewable and sustainable energy, 133, 2, 206.
Wang, S., Orense R. P., (2014). Modelling of raked pile foundations in liquefiable ground. Soil Dynamics and Earthquake Engineering, 64, 11–23.
Wang, W., Feng, Q., Yang, C., (2019). Investigation on the dynamic liquefaction responses of saturated granular soils due to dynamic compaction in coastal area. Applied Ocean Research, 89, 273-283.
Zhang, H.W., Sanavia, L., Schrefler, B.A., (2001). Numerical analysis of dynamic strain localisation in initially water saturated dense sand with a modified generalized plasticity model. Computers and Structures, 79, 441-459.
Zhang P., Ding, H. and Le, C., (2014). Seismic response of large-scale prestressed concrete bucket foundation for offshore wind turbines. Journal of renewable and sustainable energy, 6, 013127.
Zerfa, F.Z., Loret, B., (2003). Soil Dynamics and Earthquake Engineering, 23, 435-454.
Zienkiewicz, O.C., (1980). Constitutive laws and numerical analysis for soil foundations under static, transient or cyclic loads. Appl. Ocean Res. 2, 1.
Zhou, C., Jiang, H., Yao, Z., Li, H, Yang, C., Chen, L., Geng, X., (2020). Evaluation of dynamic compaction to improve saturated foundation based on the fluid-solid coupled method with soil cap model. Computers and Geotechnics, 125, 103686.
Zhu, B., Ren, J. and Ye G., (2018). Wave-induced liquefaction of the seabed around a single pile considering pile-soil interaction. ISSN, 1064-119.
Zuo, H., Bi, K., Hao, H., (2018). Dynamic analyses of operating offshore wind turbines including soil-structure interaction. Engineering Structures, 157, 42-62.
劉欣雨, (2020). 「離岸風機結構與土壤互制之探討」, 碩士論文, 國立成功大學土木工程學系結構工程組。