2019 Fiscal Year Final Research Report
Development of a novel tracer test using two solutions for measuring field saturation and effective porosity
| Project/Area Number |
17K00615
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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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| Research Field |
Modeling and technologies for environmental conservation and remediation
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| Research Institution | Okayama University |
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Principal Investigator |
Komatsu Mitsuru 岡山大学, 環境生命科学研究科, 准教授 (50325081)
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| Co-Investigator(Kenkyū-buntansha) |
小泉 圭吾 大阪大学, 工学研究科, 助教 (10362667)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 体積含水率 / 有効間隙率 / 擬似飽和状態 / 現場飽和状態 / 原位置試験 / 土中水分計 / トレーサー / エタノール水溶液 |
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| Outline of Final Research Achievements |
Recently, setting thresholds for soil water content for predicting slope disasters and setting appropriate physical parameters for soil and groundwater pollution have become issues. The objectives of this study were to propose an easy-and-quick in-situ testing method to find the effective porosity in natural ground, and to apply the method to confirm the quasi-saturated state and the field saturated state using two solutions. An in-situ test was conducted using the developed prototype tracer injection device. The results of the in-situ test were evaluated based on the findings of laboratory permeability tests using specimens sampled on site as well as precipitation experiments using the site model. The quasi and field-saturated volumetric moisture content measured in the in-situ experiments were found generally consistent with the laboratory results. It was, however, suggested that further improvements on the specific gravity of tracers and the injection device have to be made.
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| Free Research Field |
地盤工学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で開発した試験装置は，センサーの計測範囲のわずかな間隙に注入するだけで良いので，ごく短時間で試験を終了することができる。また，センサーをそのまま長期観測に用いることもできる。そのため，多点での試験が容易に実施でき，さらに注入条件を変化させた上で有効間隙率を定量的に把握することが可能となるため，降雨強度や地下水の上昇速度に応じた現場飽和状態の判断ができるようになる。本手法が広く実務で使われるようになると，透水係数に比べて測定事例の少ないパラメータであった有効間隙率が様々な土質に対してデータの蓄積が行われるようになり，現場飽和状態の指標を示すデータベースの構築につながるものと考えられる。
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