陳榮河臺灣大學:土木工程學研究所王元佐Wang, Yuan-TsoYuan-TsoWang2007-11-252018-07-092007-11-252018-07-092006http://ntur.lib.ntu.edu.tw//handle/246246/50592地工合成材經多年之發展與推廣,已於國際工程界廣泛使用,舉凡地盤改良、邊坡加勁、加勁牆、路基、河海岸與水土保持工程等都有。其中,蜂巢格網是以提供土壤圍束作用做為加勁機制,可以改善軟弱路基土壤強度及防止邊坡沖刷,其格室更可作為植生美化之用;另外,其體積小,易收存、施工簡單、用地省,並能達到安全之要求。 本研究之主要目的是建立蜂巢格網擋土結構數值分析模式,以索元素(cable element)簡化模擬不同材料間之界面元素(interface element),;模擬對象是以蜂巢格網擋土結構之模型試驗作為依據,以探討不同牆高、牆面傾角、擋土結構型式、荷重加載區及背填土加勁等影響因素。 根據數值分析結果顯示,蜂巢格網擋土結構的牆面水平位移量與背填土沉陷量,隨著牆面傾角及背填土荷重之提高而增加。蜂巢格網設置為牆面式較重力式產生較大之水平位移,其最大水平位移發生在0.65倍牆高處。背填土加勁可有效地減少牆面的水平位移量與背填土沉陷量。上層加勁時,牆體呈凸型變化,其最大水平位移量約發生在0.8倍牆高處。下層加勁時,牆體則呈傾斜型,牆下方加勁處之位移較小,但上部則較大,牆面最大水平位移量發生在牆頂處。隨著牆面傾角增加潛在滑動面會向牆體後方延伸,且擋土結構有翻倒破壞之傾向;此外於背填土加勁之結構其破壞面會沿加勁區與非加勁區邊界發展。After years of development and advancement, geosynthetics has been extensively used worldwide. For example, it has been applied in ground improvement, reinforced slope, reinforced soil retaining wall, channel protection, and soil and water conservation. Among them all, geocell offers confining pressure to improve the bearing capacity of soft foundation. It also prevents soil erosion and creates better slope appearance. Besides, what makes it distinct from other material are its smaller volume, convenience for storage, simple process of construction, space-saving quality, and safety. The purpose of this study is to establish a numerical model of geocell retaining structures by using structural cable elements to simplify the simulation of many interfaces among different interfaces. Meanwhile, geocell retaining structure model test are used to compare and discuss how structure height, structure inclination, surcharge loading type, and construction form of geocell retaining structures affect the test results. The results of analysis show that the structural displacement and backfill settlement increase as structural inclination and surcharge loading rise. The Face-type geocell, wall, produces more horizontal displacement than gravity-type structure. The maximum displacement occurs in at height 0.65 times higher than the height of the wall. Backfill reinforcement can reduce the displacement and settlement effectively. When the upper layers of backfill are reinforced, the wall would protrude and the maximum displacement occurs in at height 0.8 times the height of the wall. When the lower layers of backfill are reinforced, the biggest displacement occurs in the part on the top. Displacements in the rest parts are relatively smaller. As the wall inclination increases, the potential slip surface expands backward and the wall tends to overturn. In addition to that, the slip surface would expand along the line between the reinforced and the un-reinforced zones.誌 謝 I 摘 要 II ABSTRACT III 目 錄 IV 表 目 錄 VII 圖 目 錄 VIII 照 片 目 錄 XII 符 號 說 明 XIII 第一章 導論 1 1.1 研究動機與背景 1 1.2 研究目的與方法 1 1.3 研究內容 2 第二章 文獻回顧 4 2.1蜂巢格網簡介 4 2.2 蜂巢格網之相關研究 8 2.3蜂巢格網加勁擋土牆穩定性分析 24 2.4 加勁擋土牆的數值分析 27 第三章 蜂巢格網擋土結構模型試驗 30 3.1模型相似率 30 3.2實驗室模型試驗 32 3.3蜂巢格網擋土結構模型試驗之結果 34 第四章 分析程式簡介與分析模式之建立 47 4.1 FLAC程式概述 47 4.2 FLAC基本術語定義與指令說明 48 4.3 FLAC組成律模式 50 4.4 FLAC內建結構元素 51 4.5 砂土與加勁砂土之力學性質 54 4.5.1三軸試驗與結果 54 4.5.2 數值分析之力學參數 54 4.5.3 Duncan-Chang雙曲線模式 63 4.5.4 力學模式之驗證 66 4.6 分析模式 71 4.6.1幾何相似定律 71 4.6.2模型建立 76 4.6.3 邊界條件 76 4.6.4 土壤元素模擬 76 4.6.5 加勁材料模擬 78 4.6.6牆面之模擬 80 4.7 蜂巢格網擋土牆建造 80 第五章 數值分析結果討論與驗證 83 5.1 蜂巢格網擋土結構數值模擬結果 83 5.1.1 擋土結構傾角之影響 83 5.1.2 荷重加壓區域之影響 84 5.1.3 背填土有無加勁之影響 85 5.1.4 擋土結構形式之影響 85 5.1.5 背填土加勁區域之影響 86 5.2 數值分析之驗證 86 5.3 破壞滑動面之探討 88 第六章 結論與建議 108 6.1 結論 108 6.2 建議 110 參考文獻 111 附錄一 三軸壓縮試驗之數值模擬程式碼 116 附錄二 蜂巢格網擋土牆基本模型程式碼 121en-US蜂巢格網加勁牆數值分析力學行為geocellreinforced wallnumerical analysismechanical behavior蜂巢格網擋土結構之數值分析Numerical Analysis on Geocell Retaining Structuresthesis