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標題: 梳子壩受土石流衝擊時動態行為之研究
The Impact Force of Debris Flow on The Slit Dam
作者: 陳致穎
關鍵字: slit dam;梳子壩;debris flow;acceleration meter;impact force;土石流;加速度計;衝擊力
出版社: 土木工程學系

Due to the weakness of geologic condition in Taiwan, with the short and rigid flow in the streams, the typhoon and heavy storm often happen because of Taiwan locating at tropic region. It mainly causes the debris flow and other slope destruction. With the rigid debris flow, it contains a large amount of devastative power, which would affect a large spread of areas. Recently, under the over excavation of the slopes, the damage caused by debris flow has became essentially especially after the 921 Chi-Chi earthquake. The occurring possibility of debris flow is arisen out of the weakening geologic situation.
With the use of Equal-Weight Replacement Method, the grain size distribution curve obtained by the in situ grain size can be correlated. The impact experiment is performed in the water flume. The soil pressure meter and acceleration meter are attached to the sambo dam model stricken on the water flume. Through the Automatic Data Log System, the dynamic behavior and reaction on the sambo dam can be recorded when the impact produced by the debris flow. And the research is aim to study the impulsive force and corresponding blocking effect on sambo dam. It is assumed that the cross section of sambo dam is in the form of inhomogeneous cantilever beam. By the measurement of vibrating acceleration at the free end, respect to the integration with time, it estimates the relationships between velocity & time and displacement & time. Consequently, the assumption of statically lateral-elastic stiffness is assist to assess the impulsive force and then, the resultant force and its location acting on the sambo dam under the impact of debris flow can be calculated.
The research result reveals that the greater the impulsive force, the higher the inclination of sambo dam. It also increases the sand-retaining ratio and separation power of the dam. The central part of sambo dam receives the most of impulsive force that is greater than its lateral sides. Decreasing the inclining angle of sambo dam, it is obviously lower the impact acted by the debris flow. The location of resultant-impulsive force can sound reasonably because it ranges from 0.112m (3L/8) to 0.15m (L/2) far from the base of sambo dam. And that location is also the same as the result (0.11m [L/3] from the base) derived by Lin (1994) with perspective to the dynamic pressure of fluid.
Appears in Collections:土木工程學系所

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