Relation between Debris Flow Rheology and Fan Deposit Morphology Investigated Using Small-scale Experiments
Date Issued
2011
Date
2011
Author(s)
Hung, Chi-Yao
Abstract
The aim of this thesis is to understand the relationship between rheology and morphology for debris flow going from a narrow valley to a fan. In micro-scale experiments, Kaolinite, black sand and water are mixed to represent debris flows of high viscosity. We change two parameters which are water content and the coarse particle content to observe variation in debris flow behavior due to changes in composition. To measure the fast flow and rapid deformation of the flow surface, a fast scan method using a high speed camera and rotating laser are developed. The results of the experiments are analyzed in two parts, one is channel flow behavior and another is the canyon-fan transition. In channelized results beside compare the experiments, we use kinematic wave to simulate the surge process in channel, and compare the cross section in field. At the canyon-fan transition, debris flow deposit in two stages. In the first stage, a high speed front advance on to fan. In the second stage, the slower tail tends to spread laterally. Increasing water content and decreasing coarse particle content makes the first stage longer and the second stage shorter. As a result, lateral deposits are few pronounced. Finally, the experimental results are compared with field observations.
Subjects
debris flow
fast scan method
mirco-scale experiment
image analysis
Type
thesis
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