臺灣博碩士論文加值系統

在加勁擋土結構物的內部穩定設計上，加勁材的張力強度與張力分佈為主要的關鍵。現今有許多方式可以用來評估加勁材受力後的張力分佈情況，主要可區分為以力平衡（如側向土壓法、極限平衡法)與以變形（如K 勁度法、有限元素法）為考量的評估方法。但至目前為止，各評估方法的綜合分析與比較之相關研究相當不足。有鑑於此，本文選用兩個同為3.6 公尺但牆面勁度不同之加勁擋土結構物，分別為柔性回包式牆面及剛性混凝土塊牆面，利用實測資料與各項評估方法的預估值進行比較，探討其準確性及可能造成誤差的原因。研究結果發現，K 勁度法在結構物加載後，明顯低估加勁材張力值；有限元素法能準確預測加勁材實際的張力發展；此外，剛性牆面能抵制結構物的側向變形，導致剛性牆面加勁擋土結構物其加勁材張力發展比柔性牆面來的小。然而，以力平衡為考量的預測方法並未考慮牆面的影響，因此普遍呈現高估的趨勢。

Proper estimation of reinforcement loads is a key to evaluate the internal stabilities of Geosynthetic-Reinforced Soil (GRS) structures. Prediction methods for reinforcement loads within GRS structures in current practice can be categorized into two approaches: force equilibrium approach (i.e., earth pressure method and limit equilibrium method) and deformation based approach (i.e., K-stiffness method and finite element method). Until today, the effects of these methods have not been extensively examined and compared yet. In this paper, the reinforcement loads measured from two full-scale and carefully instrumented GRS walls are used to examine the prediction of reinforcement loads by the aforementioned methods. These walls are 3.6m high with different facing stiffness; one wall was constructed with a stiffer segmental modular block face and the other with a flexible wrapped-around face. Comparison results from both wall cases indicate the force equilibrium approach overly predict the reinforcement loads. The K-stiffness method shows an obvious underestimate under surcharging conditions. The finite element predictions are sufficiently accurate under working stress conditions but do not successfully predict the measured reinforcement loads under large loading conditions. Furthermore, a stiff facing in a reinforced soil wall can restrain wall deformation and thus result in significant reductions in reinforcement loads compared to the flexible facing system. However, the influence of facing stiffness is typically not accounted for in the force equilibrium approach, so that the force equilibrium approach significantly overestimates reinforcement loads for the stiff face wall. Reasons of discrepancy between predicted reinforcement loads and measured data are discussed. The results obtained from this study provide insightful information for the design of GRS structures.

摘 要
ABSTRACT
誌 謝
目 錄
表目錄
圖目錄
第一章 緒論
1.1 前言
1.2 研究動機與目的
1.3 研究方法
1.4 論文架構
第二章 文獻回顧
2.1前言
2.2 加勁擋土結構
2.2.1 地工合成材料類型
2.2.2 牆面版類型
2.3 加勁材張力預測方法
2.3.1側向土壓法
2.3.2極限平衡法
2.3.3 K勁度法
2.3.4 連體力學法
第三章 足尺寸加勁擋土牆試驗
3.1 加勁牆描述
3.1.1 剛性混凝土模塊加勁牆
3.1.2 柔性回包式加勁牆
3.2 土壤
3.3 加勁材
3.4 量測設備
3.5 建造與附加載重
3.6 試驗結果
第四章 加勁材張力評估
4.1 側向土壓法
4.1.1 Rankine’s Method
4.1.2 Coulomb’s Method
4.2 極限平衡法
4.3 K勁度法
4.4有限元素法
第五章 不同牆面版預測結果比較
5.1 柔性加勁牆
5.1.1 各階載重下之加勁材張力比較
5.1.2 單層加勁材Tmax比較
5.1.3 各層加勁材張力總合Tmax
5.2 剛性加勁牆
5.2.1各階載重下之加勁材張力比較
5.2.2 單層加勁材Tmax比較
5.2.3各層加勁材張力總合Tmax
5.3 小結
5.4 不同牆面版之加勁材張力比較
第六章 誤差原因討論
6.1 誤差來源
6.2 土壤剪力強度選擇
6.3 剪脹角的影響
6.4 量測誤差
6.5 不飽和土壤之視凝聚力
6.5.1 非飽和砂土無圍壓縮試驗
6.5.2 視凝聚力影響
6.6 牆面版勁度影響
6.6.1 極限平衡法中考慮柔性加勁牆牆面勁度
6.6.2極限平衡法中考慮剛性加勁牆牆面勁度
6.6.3 小結
6.6.4 以楔形破壞討論牆面效果
6.7 綜合評估
第七章 結論與建議
7.1 結論
7.2 建議
參考文獻

AASHTO, (2002), “Standard Specifications for Highway Bridges”, American Association of State Highway and Transportation Officials, 17th Edition, Washington, DC, USA, 689 p
Allen, T.M.; Bathurst, R.J.; Holtz, R.D.; Walters, D.; Lee, W.F. (2003) “A New Working Stress Method for Prediction of Reinforcement Loads in Geosynthetic Walls”, Canadian Geotechnical Journal, v 40, n 5, p 976-994
Bathurst, R.J., Miyata, Y., Nernheim, A. and Allen, T.M. (2008) “Refinement of K-Stiffness Method for Geosynthetic Reinforced Soil Walls”, Geosynthetics International, v 15, n 4, p 269–295
Bathurst, R.J., Vlachopoulos N., Walters, D.L., Burgess, P.G., and Allen, T.M. (2006). “The influence of facing stiffness on the performance of two geosynthetic reinforced soil retaining walls”, Canadian Geotechnical Journal, v 43, n 12, p 1225-1237
Bathurst, R. J., Allen, T. M. & Walters, D. L. (2005). “Reinforcement Loads in Geosynthetic Walls and the Case for a New Working Stress Design Method”. Geotextiles and Geomembranes, 23, No. 4, 287–322.
Bathurst, R.J., Vlachopoulos N., Walters, D.L., Burgess, P.G., and Allen, T.M. (2006). “Full Scale Testing of Geosynthetic Reinforced Walls” ,ASCE Special Publication, Proceedings of GeoDenver 2000, D.C. August
Elias, V., Christopher, B.R., and Berg, R.R., (2001), “Mechanically Stabilized Earth Walls and Reinforced Soil Slopes Design and Construction Guidelines” Report No. FHWA-NHI-00-043, National Highway Institute, Federal Highway Administration, Washington, D.C. March
Hatami, K and Bathurst R. J.(2006), “Numerical Model for Reinforced Soil Segmental Walls under Surcharge Loading” Canadian Geotech Journal, v 67, n 4, p 1066-1085
Hatami, K and Bathurst R. J.(2005), “Development and Verification of a Numerical Model for the Analysis of Geosynthetic-Reinforced Soil Segmental Walls under Working Stress Conditions”, JGGE, v 132, n 6, p 673-684 Liu and Yang, (2012), International Geosynthetics Society Student Award Competition
Huang B., Bathurst R. J. and Hatami, K (2009), “Numerical Study of Reinforced Soil Segmental Walls Using Three Different Constitutive Soil Models”, JGGE, v 135, n 10, p 1486-1498
Holtz, Robert, (2010), “Reinforced Soil Technology: From Experimental to the Familiar”, 46th Karl Terzaghi Lecture, Geo-Institute of American Society of Civil Engieers, GeoFlorida Conference, West Palm Beach, Florida.
Karpurapu, R.G., and Bathurst, R.J. (1995). “Behaviour of Geosynthetic Reinforced Soil Retaining Walls Using the Finite Element Method”. Computers and Geotechnics, 17(3): 279–299.
Leshchinsky, D. (2010) “Geosynthetic Reinforced Walls and Steep Slopes: Is It Magic”, Geosynthetics Magazine, Vol. 28, No. 3, pp16-24
Leshchinsky, D. (2009) “On Global Equilibrium in Design of Geosynthetic Reinforced Wall”, JGGE, ASCE, Vol. 135, No. 3, pp.309-315
Ling, H.I., Cardany, C.P., Sun, L.-X., and Hashimoto, H. (2000). “Finite Element Study of a Geosynthetic-Reinforced Soil Retaining Wall with Concrete-Block Facing”. Geosynthetics International, 7(3): 163–188.
Lopes, M.L., Cardoso, A.S., and Yeo, K.C. (1994). “Modelling Performance of a Sloped Reinforced Soil Wall Using Creep Function”.Geotextiles and Geomembranes, 13:181–197.
National Concrete Masonry Association, (2010), “Design Manual for Segmental Retaining Walls”, Bathurst, R.J., Editor, 3rd Edition, Herndon, Virginia, USA, 282p.
PLAXIS. (2005). “Plaxis Finite Element Code for Soil and Rock Analyses”, Version 8.2, P.O. Box 572, 2600 AN Delft, The Netherlands (Distributed in the United States by GeoComp Corporation, Boxborough, MA).
Yang, K. H., Zornberg, J.G. and Bathurst, R.J. (2010) “Mobilization of reinforcement tension within geosynthetic-reinforced soil structures” , Geotechnical Special Publication, 2010, Earth Retention Conference 3, v 384, n 208 GSP, p 494-501,
Zornberg, J.G., Sitar, N., and Mitchell, J.K. (1998) “Limit Equilibrium as Basis for Design of Geosynthetic Reinforced Slopes.” Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 124, No. 8, pp. 684-698.