Fan surface evolution, grain motions, and subsurface deposition patterns in small-scale experiments

碩士 === 國立臺灣大學 === 土木工程學研究所 === 102 === The purpose of this thesis is to investigate the development of alluvial fans using small-scale laboratory experiments. The experiments start from a bed of uniformly mixed coarse and fine grains, with water flow confined to a pilot channel. Material incised fro...

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Bibliographic Details
Main Authors: Szu-Ying Chen, 陳思穎
Other Authors: 卡艾瑋
Format: Others
Language:en_US
Published: 2014
Online Access:http://ndltd.ncl.edu.tw/handle/49489600206492815006
Description
Summary:碩士 === 國立臺灣大學 === 土木工程學研究所 === 102 === The purpose of this thesis is to investigate the development of alluvial fans using small-scale laboratory experiments. The experiments start from a bed of uniformly mixed coarse and fine grains, with water flow confined to a pilot channel. Material incised from the bed is then transported to a flat area where an alluvial fan develops. Water flow over the fan splits into channels which evolve over time. Three experiments are analyzed in detail for conditions of low, medium, and high discharge. To document the resulting evolving morphology and stratigraphy, three imaging methods are used. Topography is measured at repeat intervals using a laser scan system. Stratigraphy is characterized at the end of each experiment by cutting and photographing transverse slices across the fan. During flow, particle tracking velocimetry is performed using a moving camera to track the motions of coarse grains over the bed. By combining results from these three methods, it is possible to relate the final fan topography and stratigraphy to observations of channel evolution during flow.