| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 94 === Taiwan is located in the subtropical area. When the typhoon strikes, the heavily rain fall and rushing rivers make the geology more fragile, especially after the powerful earthquake on the 21st of September. Nevertheless, the Tao-Zhi Typhoon, the most serious damage in 2001, caused destructive debris flow in Hualian and Natou Counties. Due to the uniqueness of debris flows and strong destruction, the deadly strikes seriously threaten people’s safety and properties in the downstream area. Therefore, it is urgent to capture a deeper understanding of the characteristics of debris flow and calamity prevention. However, there is very limited research on the consistency of debris flow and landslides in connection with blocking ability by dam entities.
This study is to experiment the relationship between the consistency of debris flow and fine-textured soil to the blocking ability by dam entities. In this experiment, simulating the Shen-Mu Village in situ grading curve by equal weight composing modification and changing the content of fine-textured, using three kinds of fine-textured soil and debris consistency to test the basin model experiment of debris flow by taking the concrete slit dams, steel grid dams and gravity dams of blocking debris flow. To observe the condition of different soils flowing, pile up, and the impulse to the dams; further, to analyze the result of three kinds of dams and discuss the effects of blocking and pile-up of different dams for debris consistency and ratio of fine-textured soil.
The result shows when the consistency increased, there is strongly influence on the blocking and piling up, especially on permeability dams. With the increasing of detention rate and fine-textured soil content, it is evidence to see the decreasing of grain separation effect. The percentage of grain separation of the steel grid dams is over 65 percent and the gravity dams is more than 70 percent, but the concrete slit dams is sharply decrease with the increasing of fine-textured soil. When the 15% of fine-textured soil and 0.75 of detention rate, the grain separation effect drops from 75% to 45%. For the coarse grain and separation efficiency, the steel grid dams show the separation significance in some degree, and the concrete slit dams show have a better outcome in the coarse grain, but insignificance in the separation efficiency. However, there is no significant separation effect found in the gravity dams.
The study also uses different materials of ball to discuss the debris flow and the impulse of single ball with regression analysis. To analyze the flowing speed of single ball and the parameter of maximum grain size, the result shows the higher E value and the bigger grain size, the more impulse will increase.
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