摘要(英) |
Mountain floods accompanied with landslides, slope avalanches and debris flows often cause tremendous disasters to downstream residents and infrastructures. The dynamic process and deposit mechanism of alluvial fans by torrential flows is experimentally explored in this study. An acrylic flume experiment is adopted to observe the deposit process of granular flows, deposit angle of topset, infiltration of granular ,and flow patterns with a high-speed camera. The particle size (D), water discharge (Qw), granular discharge (Qs) , and bed length(L) dominates the flow patterns, and the slopes of topset mainly depend on the ratio of granular discharge to water discharge.The slope of topset increases with increasing sediment concentration ,but increasing abruptly exceeding a specific value. The velocity profiles of the flowing layer are explored by using particle image velocimetry (PIV). The velocity profiles in the flowing layer depict SSH rheology when the free surface is substantially higher than granular-flow surface. When the free surface is substantially equal to granular-flow surface, the velocity profiles approximates linear. |
參考文獻 |
[1] Armanini, A., Capart, H., Fraccarollo, L., and Larcher, M. (2005).
Rheological stratification in experimental free-surface flows of
granular–liquid mixtures. Journal Of Fluid Mechanics, 532, 269-319.
[2] Lucy Clarke , Timothy A. Quine, Andrew Nicholas(2009).
An experimental investigation of autogenic behaviour during alluvial
fan evolution.
[3] Chou, H. T., Lee, C. F., Chung, Y. C., and Hsiau, S. S. (2012a).
Discrete element modelling and experimental validation.
[4] Gilbert, G. K. (1890). Lake Bonneville. Monographs of the U. S.
Geological Survey, 1, 438 p.
[5] GDR MiDi. (2004) “On dense granular flow.” European Physical
Journal E, 14(14), 341-365
[6] Jop, P., Y. Forterre, and O. Pouliquen (2005) “Crucial role of
sidewalls in granular surface flows: consequences for the rheology.”
Journal of Fluid Mechanics, 541, 167-192
[7] Pouliquen, O. (1999) “Scaling laws in granular flows down rough
inclined planes.” Physics of Fluids, 11, 542
[8] Luigi Fraccarollo • Michele Larcher • Aronne Armanini(2007)
Depth-averaged relations for granular-liquid uniform flows
over mobile bed in a wide range of slope values
[9] Erica J. Powell, Wonsuck Kim, and Tetsuji Muto(2012).
Varying discharge controls on timescales of autogenic storage
and release processes in fluvio-deltaic environments:Tank
experiments
[10] Maurits van dijk, Maarten g. kleinhans, George postma and Erin
kraal(2012). Contrasting morphodynamics in alluvial fans and fan
deltas:effect of the downstream boundary
[11] Hirotaka Ochiai. Yasuhiko Okada. Gen Furuya.Yoichi Okura .
Takuro Matsui .Toshiaki Sammori . Tomomi Terajima.Kyoji
Sassa(2004) . A fluidized landslide on a natural slope by artificial
rainfall
[12] Kyoji sassa (2000) Mechanism of flows in granular soils
[13] Gonghui Wang, Kyoji Sassa(2002) Pore-pressure generation and
movement of rainfall-induced
landslides: effects of grain size and fine-particle content
[14] Thielicke, W., Stamhuis, E. J., D’Errico, J., Schwarz, D. M., Long,
D.,Garcia, D., et al. (2010). PIVlab - time-resolved particle image
velocimetry (PIV) tool.
[15]吳俊銓(2012). 山洪濁流形成沖積扇之實驗研究. 國立中央大學
土木工程研究所碩士論文. |