指導教授:陳榮河臺灣大學:土木工程學研究所施瑋庭Shih, Wei-TingWei-TingShih2014-11-252018-07-092014-11-252018-07-092014http://ntur.lib.ntu.edu.tw//handle/246246/260736加勁擋土牆由設計方法不同,可分作Mechanically Stabilized Earth Walls(MSEW)與Geosynthetics Reinforced Soil Composites(GRSC)。前者之設計理念與背拉式擋土牆接近,後者則是將其視為複合材料進行設計。本研究應用PLAXIS之數值軟體,以數值模擬的方式,探討不同設計概念之加勁擋土牆,在受到以擬靜態方法模擬土石流衝擊力的側向荷載時,牆面與牆頂之變形行為、加勁材受力情形,牆背土壓力分佈情形、以及牆體穩定性之變化。內容共分為:(1)改變加勁區範圍(2)加勁材間距變化(3)單側與雙側疊塊式牆面之比較(4)使用不同剪力強度參數之內填土(5)疊塊式牆面與灌漿式牆面之比較(6)持續加載或間歇性加載之結果差異等六大主題進行討論。 由研究結果發現,若內填土壤的剪力強度較弱、或雙面疊塊式擋土牆之厚度較薄,在受到側向壓力時,牆面容易出現較大的變形,且無法承受過大的側向壓力即發生破壞。牆面構築型式亦會影響牆面變形,若牆面為連續體時,因剛度較高,故在相同的側向壓力作用下,灌漿式牆面擋土牆之牆面變形量較小,安全穩定性亦較高。加勁擋土牆之牆頂變形量會隨著加勁區範圍變大而減少。牆背之土壓力分佈與加勁材之間距有關,若間距愈大,則層間土壤承受之土壓力愈小。又當雙面式疊塊擋土牆受到側向壓力時,於後方牆趾處會有應力集中的現象。若改變加勁區範圍或加勁材間距改變,在施加小荷重的情形下,因側向壓力會抵消部分土壓力,反而有助於牆體的穩定;但當荷載逐漸增大,牆體開始出現被動式破壞,故安全係數會隨著施加的側向壓力變大而有先升後降的情形。若牆體受到間歇性荷載,會有部分土壓力蓄積於牆背無法消散,而牆面與牆頂變形以及安全係數等,在加壓前後則沒有太大變化。Geosynthetic-reinforced soil walls can be classified into two types according to the design concept: Mechanically Stabilized Earth Walls (MSEW) and Geosynthetics Reinforced Soil Composites (GRSC). The former is designed and constructed in the same manner as a tied-back wall; while the latter is treated and designed as a composite material. In this study, the finite element software, PLAXIS, was used to analyze the behaviors of the aforementioned two types of walls under quasi-static lateral pressures induced by debris flows. The influencing factors investigated were as follows: (1)width of reinforced zone; (2) vertical spacing of reinforcement; (3) one-faced and double-faced walls; (4) shear strength of soil; (5) block-facing and grouted-facing walls; (6) continuous loading and periodic loading. The results showed that the deformation at the top of the walls decreased as the width of reinforced zone increased. The distribution of lateral earth pressure at the back of wall-facing varied with the vertical spacing of the reinforcement; as the spacing was increased, the earth pressure between two layers of reinforcement would be smaller than the earth pressure close to the reinforcement. In addition, stress concentration was observed at the heel of a double-faced wall when its front side subjected to lateral pressure. Moreover, the factor of safety tended to increase as the wall was subjected to small lateral pressure, but it then decreased with increasing lateral pressure. The factor of safety of the wall was also affected by the shear strength of soil, the thickness of double-faced wall, and the facing type of wall. In the case of periodic loading, the stresses behind the wall-facing could not be fully dissipated when unloaded. However, the periodic loadings did not affect much the deformation of the wall-facing, the settlement, as well as the factor of safety of the wall.誌謝 I 摘要 II ABSTRACT III 目錄 V 表目錄 VIII 圖目錄 IX 符號說明 XII 第一章 緒論 1 1.1 前言 1 1.2 研究動機與目的 1 1.3 研究方法 1 1.4 研究內容 2 第二章 文獻回顧 4 2.1 加勁材簡介 4 2.1.1 簡介 4 2.1.1.1 地工織物(Geotextiles) 4 2.1.1.2 地工格網(Geogrids) 5 2.1.1.3 地工複合材料(Geocomposites) 5 2.1.2 工程特性 5 2.2 加勁擋土牆 6 2.2.1 加勁原理 6 2.2.2 MSEW與GRSC之比較 7 2.2.3 應用 9 2.3 土石流整治工法 9 2.3.1 土石流簡介 10 2.3.1.1 土石流定義 10 2.3.1.2 土石流特性 11 2.3.1.3 土石流危害方式 12 2.3.2 防治工法 13 2.3.3 土石流衝擊力 14 第三章 數值模型介紹與建構 29 3.1 PLAXIS軟體簡介 29 3.1.1 土壤材料組成模式 29 3.1.2 結構元素組成模式 34 3.2 數值模擬之參數 35 3.2.1 土壤 35 3.2.2 加勁材 36 3.2.3 岩盤 36 3.2.4 面板 36 3.2.5 材料界面 37 3.3 數值驗證模型之建構 37 3.4 數值模型之建構 38 3.4.1 疊塊牆面之加勁擋土牆 38 3.4.2 灌漿牆面之加勁擋土牆 39 3.5 荷載型式 40 3.5.1 土石流衝擊力估算 40 3.5.2 加載方式 40 第四章 數值模擬驗證 51 4.1 數值分析之驗證 51 4.1.1 孔隙比影響 52 4.1.2 參考圍壓影響 52 4.1.3 膨脹角影響 53 第五章 分析結果 62 5.1 加勁區範圍之影響 62 5.1.1 牆面變形 62 5.1.2 牆頂變形 63 5.1.3 加勁材受力情形 63 5.1.4 牆背土壓力分佈 64 5.1.5 安全係數變化 65 5.2 加勁材間距 65 5.2.1 牆面變形 65 5.2.2 牆頂變形 66 5.2.3 加勁材受力情形 66 5.2.4 牆背土壓力 67 5.2.5 安全係數 67 5.3 單側或雙側疊塊式牆面之影響 67 5.3.1 牆面變形 68 5.3.2 牆頂變形 68 5.3.3 加勁材受力情形 69 5.3.4 牆背土壓力 69 5.3.5 安全係數 70 5.4 土壤材料之影響 70 5.4.1 牆面變形 70 5.4.2 牆頂變形 71 5.4.3 加勁材受力情形 71 5.4.4 牆背土壓力 71 5.4.5 安全係數 72 5.5 面板型式之影響 72 5.5.1 牆面變形 72 5.5.2 牆頂變形 73 5.5.3 牆背土壓力 73 5.5.4 安全係數 74 5.6 間歇性加載之影響 74 5.6.1 牆面變形 74 5.6.2 牆頂變形 74 5.6.3 牆背土壓力 75 5.6.4 安全係數 75 第六章 結論與建議 128 參考文獻 1305758717 bytesapplication/pdf論文公開時間:2019/08/16論文使用權限:同意有償授權(權利金給回饋本人)加勁擋土牆土石流側向荷重整治數值分析PLAXIS應用地工合成材加勁擋土牆防治土石流之研究Application of Geosynthetic-Reinforced Soil Walls for Debris Flow Mitigationthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/260736/1/ntu-103-R01521106-1.pdf