2006 Fiscal Year Final Research Report Summary
EFFECTS OF WATER ABSORPTION AND NEUTRALIZATION PROPERTIES OF CRUSHED SHELL ON STABILIZATION OF ACID SULFATE SOILS
| Project/Area Number |
16560439
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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) |
OKUMURA Mitsushi Fukui National College of Technology, Department of Civil Engineering, Associate professor, 環境都市工学科, 助教授 (70177187)
TSUJIKO Yuji Fukui National College of Technology, Department of Civil Engineering, Associate professor, 環境都市工学科, 助教授 (40259859)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Oyster shell / Acid sulfate soil / Clay / Stabilizer / California bearing ratio / Unconfined compressive strength / Impact acceleration value / Elastic modulus |
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| Research Abstract |
This study consists of two kinds of laboratory tests and a field inventory shown in the following :
The first purpose of laboratory tests is to elucidate the fluctuation mechanism of pore water caused by rise of pH which the contact with acid sulfate soil including pyrite and calcium carbonate deriving from the oyster shell induces. The second purpose of laboratory tests is to clarify the bearing capacity and strength characteristics of the mixture of acid sulfate soil, crushed oyster shell and stabilizer. On the one hand, the products expected in a field inventory are the ascertaining of a solidification of the above mixture under exposure condition and the finding of its elastic modulus.
The principal results obtained from chemical tests, mechanical experiments and measurement records at in situ are summarized as follows :
(1)Mixing a calcium carbonate and slaked lime into acid sulfate soil, the amount of pore water varies due to the water absorption reaction with formation of an iron hydroxide, the dehydration reaction with formation of an iron oxide and the volatilization of carbon dioxide with dissolution of a calcium carbonate.
(2)The unconfined compressive strength and CBR value of the mixture of acid sulfate soil, crushed oyster shell and stabilizer have become larger than those of the mixture without shell pieces. Therefore, the mixing of a crushed oyster shell into acid sulfate soil contributes to a reduction in additive content of stabilizer.
(3)According to the impact acceleration values measured on sections which have been made by using the mixture of acid sulfate soil, crushed oyster shell and stabilizer, those bearing capacities increase gradually with a passage of time, and those elastic moduli calculated by inverse analysis are greater as compared to sections which have been made by using the mixture without shell pieces.
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