2022 Fiscal Year Final Research Report
Development of a system for selecting safe routes of evacuation from landslides and floods in villages in valleys
| Project/Area Number |
20K05029
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 25030:Disaster prevention engineering-related
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 流砂 / 暗渠 / 数値計算 / ２次元浅水流方程式 / 有限体積法 / 水路実験 |
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| Outline of Final Research Achievements |
In this study, we clarified the mechanism of blockage of culverts by sediment flow such as bed loads based on flume experiments and numerical simulations. The results of the flume experiment showed that when the culvert bends or curves, sediment flow slows down in the culvert, stops, and blocks the culvert. Three-dimensional numerical simulations were performed to analyze the flow in the culvert, and it was found that the velocity of the flow decreases sharply, and the pressure of the flow rises sharply on the upstream side of the point where the shape of the culvert changes, such as bending and curving. As a result, it was estimated that the sands were subjected to drag and pressure in the opposite direction of travel, slowed down, and stopped. Therefore, as a safe evacuation route in a residential area with a culvert, it is better to remove the section where the culvert is likely to fill up during a flood.
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| Free Research Field |
砂防工学
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| Academic Significance and Societal Importance of the Research Achievements |
土石流や洪水等の水と土砂の流れを予測する数値計算手法はハザードマップを作成する基本技術で、渓流や河川などの開水路を対象として開発されてきた。この場合、流れの表面に作用する圧力は大気圧と等しく、一般的にゼロとして取り扱う。しかしながら、近年、道路が都市部だけでなく、山間部にも整備され、渓流を暗渠等で跨ぐようになった。そのような道路も含めて安全な避難路を選ぶためには、数値計算手法は開水路だけでなく暗渠も適用できなければならない。つまり、流れの表面に作用する圧力がゼロより大きい場合にも計算できるようにする必要が生じた。本研究はそのような状況も対応できる計算手法を提案し、その再現性を明らかにした。
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