Proposal of laboratory test method and consept model on water retention, permeability and evaporation properties of unsaturated soil
| Project/Area Number |
19K04602
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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 22030:Geotechnical engineering-related
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| Research Institution | Kagoshima University |
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Principal Investigator |
SAKO KAZUNARI 鹿児島大学, 理工学域工学系, 教授 (20388143)
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| Co-Investigator(Kenkyū-buntansha) |
伊藤 真一 鹿児島大学, 理工学域工学系, 助教 (20825690)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2021: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 不飽和土 / 水分特性曲線 / 透水係数 / 蒸発効率 |
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| Outline of Research at the Start |
研究代表者は，降雨時および降雨後の表層すべり型崩壊に対する斜面安定度評価システムの確立に取り組み，斜面内の不飽和浸透挙動に着目した現地斜面計測や数値解析（不飽和浸透解析＋斜面安定解析）などに取り組んできた。その中で，不飽和土の保水・透水特性，蒸発特性などを把握することが重要であることから，本研究課題では，不飽和土の水分特性曲線・不飽和透水係数・蒸発効率を同一供試体から得ることのできる室内土質試験法の提案，含水比，土の密度，粒径加積曲線から不飽和土の水分特性曲線・不飽和透水係数・蒸発効率を推定するための概念モデルの改良とその妥当性評価に取り組む。
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| Outline of Final Research Achievements |
An unsaturated seepage analysis and slope stability analysis are usually employed to estimate safety factors of slopes during rainfall. Then, the safety factor of slopes after rainfall is also important to cancel a warning on rainfall-induced slope failure. The properties of water retention, hydraulic conductivity and evaporation of unsaturated soils are important parameters to calculate a unsaturated seepage behavior and safety factor of a slope. The new laboratory experiment method for simultaneous measurement of these properties was proposed using HYPROP in this research. The validity of the measurement method was checked and points to be improved were discussed. Moreover, the mathematic model to estimate these properties was proposed based on physical and statistical consideration. The validity of the mathematical model was also inspected.
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| Academic Significance and Societal Importance of the Research Achievements |
降雨時および降雨後の斜面の安定性の定量的評価には，不飽和浸透解析と斜面安定解析を組み合わせた数値解析が用いられる。不飽和浸透特性には，不飽和土の水分特性曲線および飽和・不飽和透水係数が必要であり，また，境界条件として雨量や蒸発量が用いられるが，バルク法による蒸発量推定には，不飽和土の蒸発効率が必要となる。よって，本研究課題の成果により，これら数値解析に必要な不飽和土の土質パラメータに関する土質試験法および推定方法が確立することができれば，降雨時に発せられた警報の解除に役立つ防災情報を定量的な評価結果を基に提供するための技術に役立つことができる。
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Report
(4 results)
Research Products
(7 results)
