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標題: | 蜂巢格室擋土結構於土石流防護數值分析 Numerical Analysis of Geocell Reinforced Soil Structure for Debris Flow Mitigation |
作者: | Chen-Wei Ju 朱晟維 |
指導教授: | 陳榮河 |
關鍵字: | 蜂巢格室,擋土結構,數值分析,土石流,動態,側向荷載, geocell,reinforced retaining structure,numerical analysis,debris flow,dynamic analysis,lateral force, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 柔性之加勁擋土牆具有:高承載力、可變形性、韌性高、抗震能力優、建築時間短、可在任何地點建造,高經濟性等特點,可利用其特性進行土石流防治。本研究使用數值軟體PLAXIS,以蜂巢格室(Geocells)做為加勁材料,應用前人實驗成果將加勁區視為複合材料分析,從不同的變因:(1)加勁區的改變(2)牆面傾角的不同(3)水位線的變化,以探討蜂巢格室加勁擋土結構在受到模擬之土石流衝擊力的動態側向荷載時,牆面與牆頂之變形行為、牆背土壓力分佈情形、以及牆體穩定性之變化,最後並與GRS加勁擋土牆數值成果進行討論。
研究發現,不同變因擋土牆受動態荷載下牆面變形呈一曲線狀,完工後側向土壓力均接近三角形分佈,且均會影響擋土牆抵抗側向荷載能力。部分延長加勁在牆體穩定性和抑制變形的能力與全部加勁大約相當,更具有工程經濟性。擋土牆傾角較緩能降低牆後水平土壓力,在受到動態荷載時變形較穩定不會產生震盪。當擋土牆內側沒有水時,受側向荷載影響較大,而擋土牆內側有水時,在牆高1m以上則受側向荷載影響較大。蜂巢格室擋土牆和GRS加勁擋土牆相比較,GRS變形回復較好,變型曲線較接近線性,兩者受到動態荷載後加勁區和背填區交界處會有變形集中現象,且結構穩定度皆會降低,而因施工性不同蜂巢格室擋土牆安全係數會較GRS擋土牆來的高。 Flexible retaining walls have some characteristics:high bearing capacity, flexibility, toughness, excellent seismic resistance, short construction time, and so on. These characteristics can be used for debris flow mitigation. In this study, the finite element software PLAXIS was used to analyze the behaviors of geocell-reinforced retaining structures under dynamic lateral pressures induced by debris flows. The influencing factors investigated were as follows: (1) range of reinforced zone; (2) wall-face inclination ; (3) change of water line. The result showed that the deformation of wall face was curvilinear. Geocell-reinforced wall’s lateral earth pressure shape was like a triangle. The walls not fully reinforced had about the same stability and ability to restrain deformation as the fully reinforced walls, but were more economic. The wall with gentler inclination reduced the lateral earth pressure on the wall, and had better stability of deformation when subjected to dynamic loads. When water was inside the wall, dynamic loads influenced the lateral earth pressure slightly. Comparing geocell-reinforced walls with geosynthetic-reinforced soil walls, geosynthetic-reinforced soil walls had better deformation recovery, while geocell-reinforced walls had better structure stability. Both walls had concentration of deformation at the end of reinforced zone, which reduced the stability of the walls when they were subjected to dynamic loads. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/51528 |
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顯示於系所單位: | 土木工程學系 |
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