Stability Analyses of Geotextile Tube

[[abstract]]近年來，台灣沿海地區變遷速度早已超出想像，美麗的海岸沙灘也急速消失，種種現象不但證明海岸遭受嚴重侵蝕，而且海岸線正不斷向內陸倒退，且已逐漸嚴重威脅到沿岸結構物之安全性。本研究採砂管應用在海岸侵蝕保護，其成本低，施工簡便快速，具有相當的成效，亦可取代傳統的消波塊應用於突堤或離岸堤等消波措施，且具有環保生態觀念。本文採數值模擬分析地工砂管在受海浪沖擊時穩定性變化，特以ABAQUS設置可分離式邊界條件，受力後可表現位移或傾倒之狀況，並比較與一般模擬方式(不可分離式邊界條件)之差異，為比較其結果之差異，以高雄港旗津海岸2010年最高示性波(模擬為平時海浪模式)及近50年最高示性波(模擬為颱風海浪模式)之海浪參數為外力施加條件。先以砂管2D-極限平衡法(Hiroi1920)計算兩種外力砂管之穩定性，結果當砂管受平時海浪模式沖擊結果為穩定狀態，而受颱風海浪模式衝擊後結果為破壞狀態，其數值模擬出結果在平時海浪模式下結果亦為相同；而在颱風海浪模式下不可分離之結果位移量未達1%無破壞，而可分離模式計算結果砂管產生大量位移，整體產生10°傾覆較符合現實狀況。[[abstract]]In recent year the speed of changes in coastal area of Taiwan has already been exceeded our expectation the beautiful coast beach also disappeared at high speed All sorts of phenomena prove not only the coast is corroded seriously but also the coastline is falling back to the inland constantly It has been constituted a serious menace the security of structural things in the coast Geotube has been utilized to protect the coastal erosion It has the advantages of low cost rapid construction considerable success environmental ecological protection and can replace the traditional wave breakers for wave absorption measures on the convex dike or offshore levees This research employs numerical simulation to analyze when Geotube is impacted by the wave how to change To set the separable boundary condition with ABAQUS after it receive force the situation of displacement or dumping can be displayed and then compare the difference with the general simulation way In order to compare the difference use the highest of distributions in 2010(normal wave model) and the highest of distributions in the past 50 years (the biggest wave model) at the coast in Kaoushing Chi-Gin as the force By two-dimensional Limit Equilibrium (hiroi1920) Method calculate the stability of Geotube is stressed by the two different forces Geotube is impacted by the normal wave model is a steady state; the other is destructive But numerical simulation data show the same conclusion at the biggest wave model Geotextile doesn’t produce strain that doesn’t achieve 1% of destructive conditions in the inseparable part It produced a large amount of displacement in the separable part the result produced 10 degrees to topple conforms to the realistic conditio