근모량에 따른 식생호안의 전단강도와 침식특성 분석 = Analyses of Shear Stress and Erosion Characteristic in a Vegetated Levee Revetment with Root Fiber Quantity

국문 초록 (Abstract)

본 연구는 식생호안의 안정성 평가에 중요한 인자인 식생 근모량에 따른 식생호안의 전단강도와 침식특성을 분석하였다. 식생호안의 평균근모량은 자체 제작한 채취기를 이용하여 측정하였다. 본 연구에서 사용된 식생은 식생호안에서 다소 우점종인 달뿌리풀이다. 흐름 특성별 실험결과 근모량이 증가함에 따라 토양의 전단강도가 증가함을 확인하였고, 아울러 근모량의 증가에 따라 침식율은 지수함수적으로 감소함을 확인하였다. 식생토양의 전단강도가 증가함에 따라 침식율이 지수함수적으로 감소되어 근모량에 기인한 전단강도의 증가는 침식 저항능력의 증가를 가져왔다. 아울러 근모량에 따른 전단강도와 침식율의 상관분을 실시하여 높은 상관계수를 가진 식을 제시하였다. 식생을 가진 호안의 수리적 안정성에는 근모량의 증가에 의한 전단강도와 유수의 특성인 Froude수에 지배적임을 확인하였다.

다국어 초록 (Multilingual Abstract)

This study analyzed shear stress and erosion characteristic of a vegetated levee embankment with root fiber quantity, which is an important factor for evaluating the stability of it. The averaged root fiber quantity in a vegetated levee revetment was measured by the sampler manufactured by this research. The Phragmites Japonica Steud which is somewhat dominant species in a vegetated levee embankment was selected as an experimental vegetation. As a result of experiment of each flow regime, the shear stress was increased while root fiber quantity was increased and the erosion rate was exponentially decreased as the root fiber quantity was increased. The erosion rate was exponentially decreased as the shear stress was increased which is shown that the increase of shear stress by root fiber quantity results in the increase of erosion resistance in a vegetated soil. The relationship between shear stress and erosion rate with root fiber quantity were analyzed and their regression equations were suggested with high determination coefficients. The hydraulic stability is governed by the increase of shear stress by root fiber quantity and the Froude number of flow characteristic in a vegetated levee revetment.

참고문헌 (Reference)

1 Ikeda, S., "Width and depth of selfformed straight gravel rivers with bank vegetation" 26 (26): 2353-2364, 1990

2 Scholand, M., "Underground biomass and its influence on soil shear strength in a grazed and ungrazed German coastal marsh"

3 Yang, S. R., "Theoretical investigation on vegetation's effect made on bank safety" 1 (1): 231-241, 1998

4 Easson, G., "The effects of riparian vegetation on bank stability" 8 (8): 247-260, 2002

5 Pollen, N, "Temporal and spatial variability in root reinforcement of streambanks: accounting for soil shear strength and moisture" 69 : 197-205, 2007

6 Wu, T. H., "Strength of tree roots and slides on Prince of Wales Island" 16 : 19-33, 1979

7 Gray, D., "Mechanics of fiber reinforcement in sand" 109 (109): 335-353, 1983

8 Mafian, S., "Evaluation of root theories and root strength properties in slope stability" 30 : 594-607, 2009

9 Micheli, E. R., "Effects of wet meadow riparian vegetation on streambank erosion. 2. Measurements of vegetated bank strength and consequences for failure mechanics" 27 : 687-697, 2002

10 Millar, R. G., "Effect of bank stability on geometry of gravel rivers" ASCE 12 : 1343-1363, 1993

11 Choi, H. S., "Development of revetment safety evaluation program and introduction of manual" 42 (42): 52-58, 2009

12 Ministry of Construction and Transportation, "Development of advanced technologies for levees (in Korean)" 2004

13 Ministry of Construction, "Design Guideline for River Levee Embankment (in Japanese)"

14 Cho, J. H., "An experimental study on the reinforcement and stabilization of slope by vegetation roots" 1 (1): 54-62, 1998