Modelling of Sediment Gravity Flows with Progressive Solidification
| Autor: | Amiruddin, SASSA, Shinji, SEKIGUCHI, Hideo |
|---|---|
| Jazyk: | japonština |
| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | 京都大学防災研究所年報. B. 48:757-774 |
| ISSN: | 0386-412X |
| Popis: | 水中堆積物斜面が崩壊し流動化すると、重力の作用のもとで遠距離にわたって流走することがある。このような水中堆積物重力流の基本的な流動機構と再堆積過程を調べるために、一連の二次元水槽実験を行っている。高速CCD カメラによる流況画像情報にPIV (particle image velocimetry) 法を適用し、堆積物重力流の下方から次第に流動化土が骨組構造を回復していく過程、すなわち進行性凝固過程を明瞭にとらえている。さらに、提案解析法に基づいて水槽実験における堆積物重力流の流況の再現を試みている。また、河川堤防の破堤にともなう三次元重力流問題をとりあげ、提案解析法の適用を試みている。 The flow-out potential of a body of fluidized sediment following abrupt collapse is discussed through numerical and physical modelling. The emphasis of the analysis procedure is placed on considering the multi-phased nature of sediment gravity flows. Specifically, it combines Navier-Stokes/continuity equations for a liquefied soil domain with a consolidation equation for a solidifying soil domain. Evolutions of the flow and solidification surfaces are traced as part of solution by using a volume-of-fluid (VOF) technique. The physical modelling is concerned with two-dimensional flume tests, in which a column of fluidized sandy sediment was subjected to abrupt collapse and then allowed to flow out into ambient water. The observed and calculated results show that the sediment flow manifests itself as a decelerating gravity flow due to interactions between the flowing liquefied soil and the underlying soil with grain-supported framework being reestablished. Furthermore, a three-dimensional analysis is worked out for a class of levee breaching problems, with the aim of clarifying spread characteristics of flood water through the breached section. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|