本研究主要藉由變水頭的脫水試驗來了解淤泥與織布脫水系統下的透水率以及土顆粒滲出量，改變織布種類﹑初始泥漿高度﹑實驗時間的長短，並且分析儀器內部形成的 filter cake 結構以及基本的物理性質。系統透水率隨著 cake的厚度做非線性的遞減，卻不會因為織布種類的變化而有所改變，土顆粒滲出量 (Piping rate)會因為織布孔徑大小的不同而有所改變。整個系統與織布的透水率性質會因為織布上方 cake 形成過程中厚度與孔隙比變化而做改變，土顆粒在泥漿中自然沉降所形成cake 的壓縮指數 (Cc) = 0.7，結構近似於正常壓密的中等靈敏性黏土土樣。因此可以藉由實驗所加入的土顆粒含量與量測到的孔隙比來預測 cake 將會形成的厚度。

A falling head dewatering test was performed using a slurry containing reservoir sediment, four types of woven geotextiles, three kinds of initial water heights and different test times (10hrs ; 20hrs) to investigate the factors that control the permittivity and piping of the geotextile dewatering system. Analyzing the structure of the filter cake and the physical property by the falling head dewatering test. System permittivity non- linear decreased with the thickness of the filter cake and didn’t have change with different geotextile types. The piping rate changed with the different apparent opening sizes of geotextiles. It was found that the permittivity of the geotextile dewatering system is characterized by the thickness and the void ratio of the filter cake which progressively deposits at the upstream of the geotextile. The filter cake exhibited a normally consolidated state with a compression index Cc = 0.7 and the height of the potential filter cake can be predicted based on the total suspended solids and the void ratios measured in the present study.

參 考 文 獻
1.　Kutay, M. E. and Aydilek, A. H. (2004) “Retention performance of geotextile containers geomaterial”, Geosynthetics International, Vol. 11, No. 2, pp. 100-113

2.　Aydilek, A. H. and Edil, T. B. (2003). “Long-term filtration performance of nonwoven geotextile-sludge systems”, Geosynthetics International, Vol. 10, No. 4, pp. 110- 123.

3.　Aydilek, A. H. and Edil, T. B. (2002). ”Filtration Performance of Woven Geotextiles with Wastewater Treatment Sludge”, Geosynthetics International, Vol. 9, No. 1, pp. 41- 69.

4.　Aydilek, A. H. and Edil, T. B. (2004). “Evaluation of Woven Geotextile Pore Structure Parameters Using Image Analysis”, Geotechnical Testing Journal, Vol. 27, No. 1. pp. 1- 12.

5.　Rollin, A. L. and Lombard, G. (1988). “Mechanisms Affecting Long-Term Filtration Behavior of Geotextiles”, Geotextiles and Geomembranes, No. 7, pp.119- 145.

6.　Mlynarek, J., Rollin, A., Lafleur, J., and Bolduc, G. (1990). ”Microstructural Analysis of a Soil/Geotextile System”, Geosynthetics: Microstructure and Performance, Philadelphia, pp. 137-146

7.　Palmeria, E .M. and Gardoni, M. G. (2002). “Drainage and filtration properties of non- woven geotextiles under confinement using different experimental techniques”, Geotextiles and Geomembranes, No. 20, pp. 97- 115.

8.　Kutay, M. E. and Aydilek, A. H. (2005). “Filtration Performance of Two-Layer Geotextile Systems”, Geotechnical Testing Journal, Vol. 28, No. 1, pp. 79- 91.

9.　Aydilek, A. H., Oguz, S. H. and Edil, T. B. (2005). “Constriction Size of Geosynthetic Filters”, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 131, No. 1, pp.28- 38.

10.　Aydilek, A. H., Edil, T. B. and Fox, P. J. (2000). “Consolidation Characteristics of Wastewater Sludge”, Geotechnics of High Water Content Materials, ASTM STP, No. 1374, pp. 309- 323.

11.　Faure, Y. H., Farkouh, B., Delmas, Ph. And Nancey, A. (1999), “Analysis of geotextile filter behavior after 21 years in Valcros dam”, Geotextile and Geomembranes, No. 17, pp. 353- 370.

12.　Moo- Young, H. K., Gaffney, D.A. and Mo, X. (2002). “Testing procedures to assess the viability of dewatering with geotextile tubes”, Geotextile and Geomembranes, NO. 20, pp. 289- 303.

13.　Aydilek, A. H. (2006). “A semi- analytical methodology for development of woven geotextile filter selection criteria”, Geosynthetics International, Vol. 13, No. 2, pp. 59-72.