Hydraulic and chemical performance of a sandy soil mixed with calcium-magnesium composite as the attenuation layer for geogenic heavy metals
| Project/Area Number |
20K22433
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2020-09-11 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | Attenuation layer / Geogenic contamination / Stabilising agent / Hydraulic conductivity / Sorption / Arsenic / Soil management / Excavated soils / Hydraulic performance / Natural contamination |
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| Outline of Research at the Start |
In this research, "hydraulic and chemical performance of a sandy soil mixed with calcium-magnesium composite as the attenuation layer for geogenic heavy metals", I aim to verify the applicability of the method of laying an attenuation layer on the embankment foundation to prevent (or reduce to acceptable levels) the toxic chemicals infiltrating to the adjacent ground from the geogenic contaminated materials. This work is expected to greatly contribute to the establishment of an environmentally sustainable response to geogenic contaminated soils in Japan.
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| Outline of Final Research Achievements |
This work was carried out to evaluate the attenuation performance and hydraulic conductivity of a soil mixed with calcium-magnesium composite with different particle sizes, ranging from powder particles to granular ones. According to the hydraulic conductivity tests, the original soil and the amended soil were not significantly different in hydraulic conductivity. Batch sorption tests demonstrated that amended soil more effectively attenuates contaminants than the original soil. In one experiment, a stabilising agent of granular particles (between 2.0 and 9.5 mm) for the amendment increased the soil’s partition coefficient Kd from 14.5 to 22.2 cm3/g, which is more than a 50% improvement in the attenuation. Kd increased linearly as the particle size of the stabilising agent decreased down to 0.075 mm. Using the Kd from laboratory tests, simulations with a one-dimensional advection-dispersion equation demonstrated the durability of the attenuation layer.
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| Academic Significance and Societal Importance of the Research Achievements |
Since stabilising agent affects the mechanical and chemical properties of the attenuation layer, particle size of agent needs to be optimised as per the site requirements. Soil mixed with agent of different sizes were examined, and powder and granular particles were confirmed as suitable materials.
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Report
(3 results)
Research Products
(6 results)
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[Journal Article] Evaluating the arsenic attenuation of soil amended with calcium-magnesium composites of different particle sizes2022
Author(s)
Gathuka, L.W., Kasai, H., Kato, T., Takai, A., Inui, T., and Katsumi, T.
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Journal Title
Soils and Foundations
Volume: 62
Issue: 3
Pages: 101130-101130
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Effect of acidity on attenuation performance of sandy soil amended with granular calcium-magnesium composite.2021
Author(s)
Gathuka, L.W., Kato, T., Takai, A., Flores, G., Inui, T., and Katsumi, T.
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Journal Title
Soils and Foundations
Volume: 61
Issue: 4
Pages: 1099-1111
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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