A Study on Numerical Simulation and Flume Experiments of the Debris Flow Deposition
| Autor: | Tzu-Chun Yeh, 葉姿君 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Currently, most of debris-flow simulations and studies are those simulations of on-site debris flow situations conducted by the indoor tank test or those debris flow movements simulated by FLO-2D software, issued by O’Brien, in the light of on-site rainfall and digital terrain data. Therefore, this research uses FLO-2D with indoor tank mesh, experimental data and related parameters to make a digital analysis and to simulate the debris-flow movement. With the simulation of non-retaining test in an indoor tank by the digital program, we investigate its deposition depth, deposition form and velocity to reinforce the correlation between indoor and on-site tests to provide a verification basis for the indoor tank test. This research can be divided into two parts: the first is the establishment of digital elevation model (DEM) and the second is the analysis of program-simulated results. In conclusion, the result shows that the bigger the gradient is, the higher the velocity is but there is not obvious effect on the length, the width and the depth of depositions. However, the accuracy of deposition ranges will be declined as the gradient is increased, showing the degree of gradient will influence deposition forms and ranges in the indoor tank test. But it is not evident for such situation in the digital simulation. From the result of digital analysis, it is found that the change of volume concentration reduction rate (Cv) will have an effect on the velocity and the volume. The bigger the Cv is the increasing the volume is and the lower the velocity is. But there is not obvious effect on the deposition range. The above situation shows that the value of Cv will affect the velocity and the deposition depth but will not affect the development of deposition length and width. From the analysis of accuracy index, Ia (the similarity of impact range), it is known that the scaling factor is: 50 times＞25 times＞10 times. For the comparison of velocity analysis, it tallies with the velocity range of on-site debris flows before the dimensional analysis. It also tallies with the debris-flow velocity in the laboratory even after the dimensional analysis. From the result of velocity and accuracy analyses, it is found that it is slightly rough for the 10-time scaling factor and its accuracy is a little improper in comparison with the other two multiples. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|