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| Titel |
Numerical simulation of the inundation area for landslides induced debris flow -a case study of Hong-shui-xian gully in southern Taiwan |
| VerfasserIn |
Jinn-Chyi Chen, Meng-Ru Chuang, Ching-Jiang Jeng, Ji-Shang Wang |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074382
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| Zusammenfassung |
| Typhoon Morakot (2009) caused serious landslides and debris flows in southern Taiwan due
to intensive rainfall with long duration. The case study area of the Hong-shui-xian
gully, located in Liouguei District, Kaohsiung city, is one of the debris flows caused
by this typhoon. The watershed of the Hong-shui-xian gully has area of 34.1 ha.
The majority of the landslide debris (landslides covered 33.7% of the watershed
area) entered the main stream of the gully, where it mixed with water and became a
debris flow. Eroding the sidewalls of the stream, the debris flow entrained additional
material and traveled downstream into village and Laonong River. In this study, a
two-dimensional commercial model FLO-2D was used to simulate debris-flow inundated
area. Because the debris-flow event is highly related to landslides, how to consider
the sediment concentration due to landslides in inflow hydrograph, and to select
resistant parameters is important in the simulation work. The inflow hydrograph
that considered sediment concentration caused by flood, landslide, and debris flow
were proposed in this study. Rheological property of the debris-flow deposited
sediment was analyzed by laboratory experiment, and the rheological equations
were determined. The influence of inflow hydrograph, sediment concentration,
and roughness coefficient on the simulated results was discussed. The sediment
concentration and the roughness coefficient were calibrated by the comparison with the
debris-flow inundated area and deposited depth in field survey. The simulated results
showed that the average sediment concentration by volume of debris flow was 0.50.
The maximum deposited depth in the debris-flow inundated area was up to 6 m,
maximum velocity 5 m/s, and the deposited volume 780,000 m3. The simulated
deposited depth and inundation area showed a reasonable match to field investigation. |
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