臺灣博碩士論文加值系統

本研究分析一系列平面應變回包式牆面加勁擋土模型試驗結果以探討其垂直承載力與牆面變形特性。模型試驗所採用之背填材料為礫石與砂土，加勁材則採用四種勁度相異之PET地工格網，退縮距離採用三種不同長度。以退縮距離50cm為例，本研究之模型牆體尺寸為183cm(長)×80cm(寬)×112cm(高)。本研究試驗採用30公分寬之剛性條型基礎進行垂直加壓。試驗與分析結果顯示，未加勁擋土牆最大牆面側向位移發生於牆面頂部；加勁擋土牆最大牆面側向位移則發生於牆高中央處附近。於相同加載基腳垂直應力下，加勁擋土牆之牆面側向變形較未加勁擋土牆者小；以使用高勁度加勁材R4的加勁礫石擋土牆為例，其牆面側向變形量約較未加勁者減少十倍。於未加勁擋土牆試驗中，量測結果顯示牆面側向位移量隨著退縮距離增大而減少；然而，於加勁擋土牆試驗中，上述趨勢並不明顯。未加勁礫石擋土牆之牆面側向位移量較未加勁砂土擋土牆為小；於相同加勁材條件下，加勁礫石擋土牆之牆面側向變形亦較加勁砂土者小。綜合上述結果可知牆面側向變形受加勁材的勁度、退縮距離大小及回填材粒徑大小而影響。

In this study, the re-analyzed test results of facing deformation of a series of model tests on wrap-faced geogrid-reinforced soil (GRS) retaining wall were presented. The adopted backfill of GRS retaining wall was sand or gravel. Four types of geogrids having different nominal strengths were used. For the case of setback distance equal to 50cm, the dimensions of the model wall were 183 cm (width) × 80 cm (depth) × 112 cm (height). A strip footing of 30 cm wide, having its setback distance equal to 35cm, 50cm, or 65cm, was located on the surface of backfill to resist the applied vertical load during model test. The analyzed results indicate that the maximum lateral deformation occurs at the top of facing of unreinforced wall and at central height for reinforced case. Under the same applied footing pressure, the lateral deformation of reinforced wall is smaller than that of unreinforced one. For unreinforced wall, the lateral deformation decreases with an increase in the setback distance of footing; however, the above trend is not significant for reinforced wall. It is found that under otherwise identical conditions the lateral deformation of gravel wall is smaller than that of sand wall both for reinforced and unreinforced cases. To sum up, the lateral deformation of wrap-faced retailing wall is found to be influenced by the stiffness of geogrid, the setback distance and the particle size of backfill.

中文摘要 i
ABSTRACT ii
目錄 iii
表目錄 v
圖目錄 vi
第一章 緒論 1
1.1研究動機與目的 1
1.2研究方法 1
1.3研究內容 1
第二章 文獻回顧 2
2.1擋土牆介紹 2
2.2加勁土之加勁機制 4
2.2.1直接剪力試驗 4
2.2.2拉出與直剪試驗 6
2.3粒徑效果 10
2.4加勁擋土牆與淺基礎模型試驗 14
2.4.1全尺寸模型試驗 14
2.4.2縮尺模型試驗 14
2.5加勁擋土牆之水平變形 20
第三章 模型及儀器介紹 29
3.1模型試驗介紹 29
3.2加勁擋土牆模型 29
3.3試驗材料 33
3.3.1背填材料 33
3.3.2地工合成材 33
3.4量測儀器與資料擷取系統 33
3.4.1位移計 33
3.4.2資料擷取系統 33
3.5加載系統 40
3.6擋土牆內部土體變形監測 45
3.6.1影像設備 45
3.6.2橡皮膜與矽利康油脂 45
3.7模型填築之相關設備 48
第四章 試驗方法與規劃 52
4.1加勁擋土牆模型填築步驟 52
4.1.1前置作業 52
4.1.2擋土牆填築程序 53
4.1.3儀器架設 60
4.1.4應變計黏貼流程 66
4.2影像處理分析 72
4.2.1橡皮膜標定點之坐標擷取 72
4.2.2擋土牆內部變形之應變量計算 74
4.2.3擋土牆剪裂帶繪製 82
4.3試驗規劃 85
第五章 試驗結果與討論 91
5.1加勁擋土牆加載試驗結果 91
5.2高勁度加勁材擋土牆加載試驗結果 92
5.3基礎承載力與擋土牆牆面變形 110
5.3.1地工合成材標稱強度之影響 110
5.3.2退縮距離之影響 110
5.3.3回填材粒徑大小之影響 111
5.4加勁材之張力強度 153
第六章 結論與建議 158
6.1結論 158
6.2建議 160
參考文獻 161
附錄A牆面側向位移量紀錄表 163

1.Alfaro, M. C., Miura, N. and Bergado, D. T., 1995, “Soil-Geogrid Reinforcement Interaction by Pullout and Direct Shear Tests,” Geotechnical Testing Journal, Vol. 18, No. 2, pp. 157-167.
2.Bathurst, R. J., Walters, D., Vlachopoulos, N., Burgess, P., and Allen, T. M., 2000, “Full Scale Testing of Geosynthetic Reinforced Walls,” ASCE Special Publication, Proceedings of GeoDenver, Colorado.
3.B. Ram Rathan Lal and J. N. Mandal 2014, Model Tests on Geocell Walls Under Strip Loading, ASTM, DOI: 10.1520/GTJ20130094.
4.Jewell, R. A., 1980, “Some Effects of reinforcement on the mechanical behaviours of soils,” Ph. D. thesis, University of Cambridge.
5.Jewell, R. A., Milligan, G. W. E., Sarsby, R. W., and DuBosi, D., 1984, “Interaction between soil and grids,” Polymer Grid Reinforcement, pp. 18-30, London:Thomas Telford.
6.Jewell, R. A., and Worth, C. P., 1987, “Direct shear tests on reinforced sand,” Geotechnique, Vol. 37, No. 1, pp. 53-68.
7.Michalowski, R. L., and Shi, L., 2003, “Deformation Patterns of Reinforced Foundation Sand at Failure,” Journal of Geotechnical and Geoenvironmental Engineering, ASCE, pp. 439-449.
8.Rowe,R.K. and Ho,S.K., 1988, “Horizontal Deformation in Reinforced Soil Walls”, Can. Geotech. J. No.35, pp.312-327.
9.Yamamoto, K., Kusuda, K., 2001, “Failure mechanisms and bearing capacities of reinforced foundations,” Geotextiles and Geomembranes, Vol. 19, pp. 127-162.
10.Yoshida, T., and Tatsuoka, F., 1997, Deformation property of shear band in sand subjected to plane strain compression and its relation to particle characteristics, Proc. 14th ICSMFE, Hamburg, Vol. 1, pp. 237-240.
11.王宸豐，2009，回包式加勁擋土牆之加載試驗，國立雲林科技大學營建工程系，碩士論文。
12.李宗翰，2012，砂質回填土回包式加勁擋土牆加載試驗與其破壞樣式之觀察，國立雲林科技大學營建工程系，碩士論文。
13.林欽勝，2012，礫石回填土回包式加勁擋土牆加載試驗與其破壞樣式之觀察，國立雲林科技大學營建工程系，碩士論文。
14.施昀昇，2010，砂礫回填土加勁擋土牆模型試驗與穩定分析，國立雲林科技大學營建工程系，碩士論文。
15.陳漢生，2009，地工格網勁度與土壤粒徑對加勁擋土牆承載力與變形之影響，國立雲林科技大學營建工程系，碩士論文。