Estimation of debris flow discharge coefficient considering sediment concentration
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摘要
A sabo dam has a purpose to block the path of debris flow. However, when overflow occurs, a sabo dam works as a weir, a vertical obstruction, where the fluid must flow over. Many empirical formulas and discharge coefficients for weirs relating flow depth to discharge have been proposed to calculate overflow discharges. However, only a few studies about overflow discharge coefficients are available in the case of debris flow. In this paper, experiments and numerical simulations were done to estimate debris flow discharge coefficients by considering the sediment concentration. In the numerical simulation, a complete overflow equation and a free overfall equation were implemented to calculate debris overflow discharges at a sabo dam. To determine the discharge coefficients for each equation, single factor regression analysis was used. Laboratory experiments were done to calibrate and to compare with the simulation. Study results showed that the discharge coefficients increase as the sediment concentration increases. This finding suggests debris flow discharge coefficients are derived to calculate the debris overflow discharges at a sabo dam.
A sabo dam has a purpose to block the path of debris flow. However, when overflow occurs, a sabo dam works as a weir, a vertical obstruction, where the fluid must flow over. Many empirical formulas and discharge coefficients for weirs relating flow depth to discharge have been proposed to calculate overflow discharges. However, only a few studies about overflow discharge coefficients are available in the case of debris flow. In this paper, experiments and numerical simulations were done to estimate debris flow discharge coefficients by considering the sediment concentration. In the numerical simulation, a complete overflow equation and a free overfall equation were implemented to calculate debris overflow discharges at a sabo dam. To determine the discharge coefficients for each equation, single factor regression analysis was used. Laboratory experiments were done to calibrate and to compare with the simulation. Study results showed that the discharge coefficients increase as the sediment concentration increases. This finding suggests debris flow discharge coefficients are derived to calculate the debris overflow discharges at a sabo dam.
A sabo dam has a purpose to block the path of debris flow. However, when overflow occurs, a sabo dam works as a weir, a vertical obstruction, where the fluid must flow over. Many empirical formulas and discharge coefficients for weirs relating flow depth to discharge have been proposed to calculate overflow discharges. However, only a few studies about overflow discharge coefficients are available in the case of debris flow. In this paper, experiments and numerical simulations were done to estimate debris flow discharge coefficients by considering the sediment concentration. In the numerical simulation, a complete overflow equation and a free overfall equation were implemented to calculate debris overflow discharges at a sabo dam. To determine the discharge coefficients for each equation, single factor regression analysis was used. Laboratory experiments were done to calibrate and to compare with the simulation. Study results showed that the discharge coefficients increase as the sediment concentration increases. This finding suggests debris flow discharge coefficients are derived to calculate the debris overflow discharges at a sabo dam.
引文
Aydin, I., Altan-Sakarya, A. B.,&Sisman, C.(2011). Discharge formula for rectangular sharp-crested weirs. Flow Measurement and Instrumentation, 22, 144-151.
Bogucki, D. J.(1977). Debris slide hazards in the adirondack province of new york state. Environmental Geology, 1(6), 317-328.
Carter, R. M.(1975). A discussion and classification of subaqueous mass-transport with particular application to grain-flow, slurry-flow, and fluxoturbidites. Earth Science Reviews, 11(2), 145-177.
Dott, R. H., Jr.(1963). Dynamics of subaqueous gravity depositional processes.American Association of Petroleum Geologists Bulletin, 47, 104-128.
Egashira, S.(1993). Mechanism of sediment deposition from debris flow(part 1).Journal of the Japan Society of Erosion Control Engineering, 46(1), 45-49.(In Japanese)
El-Hady, R. M. A.(2011). 2D-3D modeling of flow over sharp-crested weirs. Journal of Applied Sciences Research, 7(12), 2495-2505.
Farhoudi, J.,&Shahalami, H.(2005). Slope effect on discharge efficiency in rectangular broad crested weir with sloped upstream face. International Journal of Civil Engineering, 3(1), 58-65.
Gonzalez, C. A.,&Chanson, H.(2007). Experimental measurements of velocity and pressure distributions on a large broad-crested weir. Flow Measurement and Instrumentation, 18(3-4), 107-113.
Harrison, A. J. M.(1967). The streamlined broad-crested weir. Proceedings of the Institution of Civil Engineers,38,657-678.
Iverson, R. M.(1997). The physics of debris flows. Reviews of Geophysics, 35(3),245-296.
Kindsvater, C. E.,&Carter, R. W. C.(1957). Discharge characteristics of rectangular thin-plate weirs. Journal of the Hydraulics Division. ASCE, 83(HY6), 1-36.
Nakagawa, H., Takahashi, T., Satofuka, Y.,&Kawaike, K.(2003). Numerical simulation of sediment disasters caused by heavy rainfall in Camuri Grand basin,Venezuela 1999., In Proceedings of the Third Conference on Debris-Flow Hazards Mitigation:Mechanics, Prediction, and Assessment, pp. 671-682. Millpress,Rotterdam.
Ohyagi, N.(1985). Definition and classification of sediment hazards. In Japanese society of soil mechanics and foundation engineering(Eds.), Prediction and countermeasures of sediment hazards pp. 5-15. Tokyo, Japan.(In Japanese)
Swanston, D. N.,&Swanson, F. J.(1976). Timber harvesting, mass erosion, and steepland forest geomorphology in the Pacific Northwest(pp). In:D. R. Coates(Ed.), Geomorphology and engineering(pp. 199-221). Stroudsburg:Dowden,Hutchinson&Ross.
Takahashi, T.(1991). Debris flow. Rotterdam:A.ABalkema.
Takahashi, T., Nakagawa, H., Harada, T.,&Yamashiki, Y.(1992). Routing debris flows with particle segregation. Journal of Hydraulic Engineering, 118(11), 1490-1507.
Van Dine, D. F.(1985). Debris flows and debris torrents in the southern Canadian cordillera. Canadian Geotechnical Jorunal, 22(1), 44-68.
Varnes, D. J.(1978). Slope movement types and processes In:R. L Schuster,&R. J. Krizek(Eds.), Landslides, analysis and control(pp. 11-33). Washington, D. C.,U.S.A.:National Research Council.
Williams, G. P.,&Guy, H. P.(1973). Debris avalanches-A geomorphic hazard In:D.R. Coates(Ed.), Environmental Geomorphology(pp. 25-46). Binghamton State University of New York Publication in Geomorphology.
Bogucki, D. J.(1977). Debris slide hazards in the adirondack province of new york state. Environmental Geology, 1(6), 317-328.
Carter, R. M.(1975). A discussion and classification of subaqueous mass-transport with particular application to grain-flow, slurry-flow, and fluxoturbidites. Earth Science Reviews, 11(2), 145-177.
Dott, R. H., Jr.(1963). Dynamics of subaqueous gravity depositional processes.American Association of Petroleum Geologists Bulletin, 47, 104-128.
Egashira, S.(1993). Mechanism of sediment deposition from debris flow(part 1).Journal of the Japan Society of Erosion Control Engineering, 46(1), 45-49.(In Japanese)
El-Hady, R. M. A.(2011). 2D-3D modeling of flow over sharp-crested weirs. Journal of Applied Sciences Research, 7(12), 2495-2505.
Farhoudi, J.,&Shahalami, H.(2005). Slope effect on discharge efficiency in rectangular broad crested weir with sloped upstream face. International Journal of Civil Engineering, 3(1), 58-65.
Gonzalez, C. A.,&Chanson, H.(2007). Experimental measurements of velocity and pressure distributions on a large broad-crested weir. Flow Measurement and Instrumentation, 18(3-4), 107-113.
Harrison, A. J. M.(1967). The streamlined broad-crested weir. Proceedings of the Institution of Civil Engineers,38,657-678.
Iverson, R. M.(1997). The physics of debris flows. Reviews of Geophysics, 35(3),245-296.
Kindsvater, C. E.,&Carter, R. W. C.(1957). Discharge characteristics of rectangular thin-plate weirs. Journal of the Hydraulics Division. ASCE, 83(HY6), 1-36.
Nakagawa, H., Takahashi, T., Satofuka, Y.,&Kawaike, K.(2003). Numerical simulation of sediment disasters caused by heavy rainfall in Camuri Grand basin,Venezuela 1999., In Proceedings of the Third Conference on Debris-Flow Hazards Mitigation:Mechanics, Prediction, and Assessment, pp. 671-682. Millpress,Rotterdam.
Ohyagi, N.(1985). Definition and classification of sediment hazards. In Japanese society of soil mechanics and foundation engineering(Eds.), Prediction and countermeasures of sediment hazards pp. 5-15. Tokyo, Japan.(In Japanese)
Swanston, D. N.,&Swanson, F. J.(1976). Timber harvesting, mass erosion, and steepland forest geomorphology in the Pacific Northwest(pp). In:D. R. Coates(Ed.), Geomorphology and engineering(pp. 199-221). Stroudsburg:Dowden,Hutchinson&Ross.
Takahashi, T.(1991). Debris flow. Rotterdam:A.ABalkema.
Takahashi, T., Nakagawa, H., Harada, T.,&Yamashiki, Y.(1992). Routing debris flows with particle segregation. Journal of Hydraulic Engineering, 118(11), 1490-1507.
Van Dine, D. F.(1985). Debris flows and debris torrents in the southern Canadian cordillera. Canadian Geotechnical Jorunal, 22(1), 44-68.
Varnes, D. J.(1978). Slope movement types and processes In:R. L Schuster,&R. J. Krizek(Eds.), Landslides, analysis and control(pp. 11-33). Washington, D. C.,U.S.A.:National Research Council.
Williams, G. P.,&Guy, H. P.(1973). Debris avalanches-A geomorphic hazard In:D.R. Coates(Ed.), Environmental Geomorphology(pp. 25-46). Binghamton State University of New York Publication in Geomorphology.