由於生態工法盛行，造就地工合成材成為各項工程施造之熱門材料，儘管地工合成材之相關研究眾多，但大多著重在滑動、傾倒、應力破壞等方面，然在水利工程之水理特性研究仍有所缺乏，緣此本研究以實驗渠道進行試驗，探討地工合成材對渠道水理特性之影響。
本研究以五種地工合成材進行試驗，流量控制在0.001cms~0.0134cms，水深控制在0.0349m~0.135m，並在距實驗渠道入流口3m處，每隔0.75m設一量測斷面，共三個量測斷面，以聲波都卜勒流速儀量測不同水深位置之流速，利用所得流速資料進行垂直流速剖面分析及曼寧係數(n)與摩擦係數(f)之探討。
經研究分析可得知，在流速分佈方面，將所量測之流速剖面無因次化，並以傳統對數律流速分佈與光滑底床流速進行比較，可發現地工合成材流速分佈之斜率與截距皆與光滑底床流速有所差異，顯示地工合成材之流速分佈偏離傳統對數律流速分佈；在平均流速方面，利用傳統流速平均法則推求水流通過地工合成材之平均流速，與設計斷面平均流速間存在誤差，因此傳統流速平均法則不適用在地工合成材平均流速之推估；在曼寧係數方面，受材料型態特性影響，不同地工合成材之曼寧係數與水深關係圖形可分為U字形與斜線形。

關鍵字：地工合成材

Due to famous of ecological engineering which makes geosynthetics to become very popular materil for engineerings. Although there are a lot of researches about studying geosynthetics, but most of them are focusing on slipping, prone, and stress fracture; however, we still lack of some focusing researches about hydraulic characteristics in Hydraulic Engineering. This research is discussing the effects of using geosynthetics in Channel’s Hydraulic characteristics by testing with experience channels.
The research is tested with five geosynthetics, controlling velocity in 0.001cms~0.0134cms, controlling water depth in 0.0349m~0.135m; and in the 3m to the entrance of experience channels has set up a measure section in every 0.75m. By using ADV to measure three measure section’s velocity in different water depth, and that can get fluid data to analysis velocity of vertical profile and discuss the relationship with Manning, s n and Friction factor f.
By analyzing the research findings, in the aspect of spreading velocity, to dimensionless forms the measurement of velocity profile comparing the traditional log-law and velocity of smooth river bed, and that finds some difference of slope and intercept between the velocity of geosynthetics and smooth river bed. Thus that shows the spread of velocity in geosynthetics far difference with traditional log-law. In the average of velocity traditional velocity average law can get the average velocity in designing section. In Manning’s Coefficient, by limiting with different materials characteristics, different geosynthetics n and its relationship with water depth can divide into U and diagonal.
Key：geosynthetics

參考文獻
1. Colebrook, C.F.(1939), “Turbulrent Flow in Pipes, with Particular Reference to the Transition between the Smooth and Rough Pipe Laws, “J.Inst.Civil Engrs.(London),February.
2. James, C S and A. L. Birkhead (2004), “Flow resistance of emergent vegetation”, Journal of Hydraulic Research, 42:390-398.
3. Kirby, J.T. and S. R. Durrans (2005), “Hydraulic resistance in grass swales designed for small flow conveyance”, Journal of Hydraulic Engineering, 131:65-68.
4. Liu, W. C., M. H. Hsu, and C. F. Wang (2003) Modeling of flow resistance in mangrove swamp at mouth of tidal Keelung river. Journal of Waterway, Port, Coastal and Ocean Engineering. ASCE 129(2): 86-92.
5. Moody, L.F.(1944), “Friction Factors for Pipe Flow, “Transactions of the ASME,66 671-684.
6. Vidal, M.H. (1978), “The Development and Future of Reinforced Earth Keynote Address, Symposium on Earth Reinforcement ASCE 28(1):1-61.
7. 朱家民(2003)，「布袋蓮對渠槽曼寧係數之影響」，國立屏東科技大學土木工程研究所碩士論文。
8. 吳富春(1994)，「渠道坡度與水深對試驗模擬植栽粗糙係數之影響」，農業工程研討會，中國農業工程學會，高雄市，137-145。
9. 許銘熙、王琪芳（2000），「植生糙度對河川流況影響之研究」，農業工程研討會論文集。
10. 康琮斌（2002），「都市排水溝淤積及植生對水流影響之研究」，國立成功大學水利及海洋工程研究所碩士論文。
11. 黃明新(1993)，「植生倒伏對水流阻力影響之研究」，國立台灣大學農業工程學研究所碩士論文。
12. 陳樹群等(2006)，「坡地抗沖蝕資材產品研發與應用技術之提升」，資源科學期刊，第28卷，第3期，186-192。
13. 游新福、黃宏斌（1992），「植生渠道阻力係數之研究」,台灣水利，第40卷，第4期，50-59。