| Project/Area Number |
13650554
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Fukui National College of Technology |
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Principal Investigator |
YAMADA Mikio Fukui National College of Technology, Department of Civil Engineering, Professor, 環境都市工学科, 教授 (30175666)
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| Co-Investigator(Kenkyū-buntansha) |
SANG Hiroaki Oita National College of Technology, Department of Civil Engineering, Professor, 土木工学科, 教授 (50187275)
OKUMURA Mitsushi Fukui National College of Technology, Department of Civil Engineering, Associate professor, 環境都市工学科, 助教授 (70177187)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | acidic soil / organic matter content / hydrogen ion exponent / oyster shell / calcium hydroxide / stabilization / improvement of subgrade soil / bearing capacity / 酸性硫酸塩土 / 含水比 / 締固め曲線 / 路床土支持力比 / 一軸圧縮強さ / 顕在的酸性土 / パイライト / CBR / コーン指数 / 斜面崩壊 |
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| Research Abstract |
The present study consists of three experiments shown in the following:
The first stage is to verify the importance of the biochemical oxidation of pyrite in the weathering process and to find the optimum pH condition for faster oxidation than in nature. The second stage is to clarify the failure mechanism of slope composed from acidic soils by the trace of physical and chemical discontinuities at the boring-core, and the third stage is to investigate the strength characteristics of soil (the pH value<5, the organic matter content>8%) stabilized by using slaked lime deriving from the crushed oyster shell.
The main results obtained from various tests are summarized as follows:
(1)The ferrous iron oxidation, given as Fe^<2+> + 1/4O_2 + H^+ → Fe^<3+> + l/2H_2O is the most important process in the biochemical oxidation of pyrite and its optimum pH value is 2.5-3.5.
(2)When we cut of the boring-core with diameter of about 65mm, length of about 12m in the 100mm interval and measured the water content, pH value, electric conductivity and ignition loss of the 92 samples, it was found that there were discontinuities differed from the physical and chemical properties at the boring-core and perhaps the slope failure was generated in these discontinuities.
(3)The unconfined compressive strength of stabilized soil increases in proportion to the lime additive content and curing time.
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