臺灣博碩士論文加值系統

本研究使用非線性有限差分程式FLAC對離岸風機負壓式沉箱基礎進行數值模擬分析，藉由模擬前人現地模型試驗，探討負壓式沉箱基礎在安裝貫入過程中以及於設計載重下之行為。透過數值模擬之結果發現負壓式沉箱基礎受力行為與文獻之研究相符合，安裝過程中以吸力輔助基礎貫入，其機制與基礎內外壓差和孔隙水滲流有關，周圍土壤應力分布以基礎為中心對稱；於設計載重下之基礎產生垂直、水平向位移與旋轉，在水平力與力矩為主要荷重下，基礎周圍側向土壓力能保持基礎穩定，直到土壓力達極限值。比較數值模擬分析與現地模型試驗結果，數值模擬分析土壤能承受極限荷重值較現地模型試驗小，但在小變形下，數值模擬分析之變形行為貼近模型試驗結果，顯示以二維數值分析模擬負壓式沉箱基礎在變形量小的範圍內可作為設計參考，但土壤能承受之極限設計載重需藉由現地模型試驗或三維數值模擬進行分析。

Suction caissons are considered as an alternative foundations for offshore wind turbines in Taiwan. This study presents numerical analyses of the installation process and bearing behavior of monopod suction caisson in sand with a finite difference technique. The results are validated with field test results in literature. It is shown that the application of suction inside the caisson is the main source for the penetration of foundations, and the soil stress distribution is symmetrical during the installation procedure. Under combined vertical, horizontal and moment loadings, the bearing capacity, sliding and overturning stability of foundations are analyzed. Among the three modes, the overturning stability is the dominated one for suction caissons stability. Comparisons with field testing results, show that the ultimate capacities from two dimension numerical simulations are smaller than the capacities of field tests.

摘要........................ I
EXTENDED ABSTRACT II
致謝....................... IX
目錄....................... X
表目錄.................... XIII
圖目錄................... XIV
第一章 緒論 1
1-1 研究背景 1
1-2 研究動機 2
1-3 研究方法與流程 3
1-4 論文架構 3
第二章 文獻回顧 5
2-1 離岸風機基礎型式 5
2-2 離岸風機設計規範 7
2-2-1 美國石油協會（API）及海岸工程手冊（CEM）規範 7
2-2-2 國際電工協會（IEC）規範 9
2-2-3 台灣離岸風場相關規範 10
2-3 負壓式沉箱基礎基本介紹 11
2-4 負壓式沉箱基礎分析相關研究 13
2-3-1 基礎安裝貫入分析 13
2-3-2 基礎受力行為分析 15
第三章 研究方法 23
3-1 FLAC程式介紹 23
3-1-1 FLAC程式基本介紹 23
3-1-2 分析流程 24
3-1-3 土壤組成模式－莫爾庫倫模式（Mohr-Coulomb Model） .............................................................................................. 24
3-1-5 結構元素 28
3-1-6 介面元素 28
3-2 負壓式沉箱基礎安裝貫入設計 30
3-3 美國石油協會（API）淺基礎設計分析建議 35
3-3-1 土壤承載力分析 35
3-3-2 抗滑動分析 41
3-3-3 淺基礎位移變形 41
第四章 負壓式沉箱基礎安裝貫入分析 43
4-1 數值分析模型 43
4-2 基礎貫入模型數值分析結果 49
4-2-1 土壤與結構互制行為 49
4-2-2 數值分析結果與文獻比較 54
第五章 沉箱基礎於設計載重下行為分析 57
5-1 分析案例 57
5-2 數值分析模型 58
5-3 沉箱基礎於設計載重下行為分析數值模擬結果 61
5-3-1 土壤與結構互制行為 61
5-3-2 數值分析結果比較 68
第六章 結論與建議 71
6-1 結論 71
6-2 建議 72
參考文獻................ 73

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