1999 Fiscal Year Final Research Report Summary
Mechanical properties and engineering classification of volcanic ash soils in Japan
| Project/Area Number |
09450183
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | HOKKAIDO UNIVERSITY (1999)
Hachinohe Institute of Technology (1997-1998) |
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Principal Investigator |
YANG JunJie Grad School of Eng., Hokkaido Univ. Rese. Asso., 大学院・工学研究科, 助手 (30253719)
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| Co-Investigator(Kenkyū-buntansha) |
YASUDA Susumu College of Sclence and Eng., Tokyo Denki Univ., Prof., 理工学部, 教授 (90192385)
MOROTO Nobuchika Faculty of Eng., Hachinohe Inst. Of Tech., Prof., 工学部, 教授 (00105545)
MLURA Seiichi Grad School of Eng., Hokkaido Univ., Prof., 大学院・工学研究科, 教授 (00091504)
KITAMURA Ryosuke Faculty of Eng., Kagoshima Univ., Prof., 工学部, 教授 (70111979)
SHIMIZU Masayoshi Faculty of Eng., Tottori Univ., Asso. Prof., 工学部, 助教授 (00115859)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Volcanic ash soil / Volcanic cohesive soil / Volcanic coarse- gained soil / Volcanic-ash organic soil / Soil structure / Shear strength / Com action / Soil stabilization |
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| Research Abstract |
1.Volcanic coarse-grained soils (1) The small strain shear modulus from in-situ and laboratory tests is independent on void ratio. Moreover, at a given void ratio and confining stress, the small strain shear modulus of cemented volcanic soils is higher than those usually observed in the case of reconstituted sands. (2) The Kussharo volcanic ash is similar to Kyushu Shirasu in shear properties, and the decrease of liquefaction strength due to freeze-thaw is small. (3) For the Kagoshima Shirasu ground, the liquefaction potential in the southern part, near coastal line and along rivers, Kagoshima City is relatively higher than one in the northern part. (4) The Shirasu particle of large particle size and large particle density demonstrate the resistance force for the erosion. 2.Volcanic cohesive soils (1) For the slope of the Kanto loam, the angle of shear resistance and cohesion also decrease with the cyclic drying-wetting and freezing-thawimg processes. For the compacted Kanto loam, we tried the evaluation of strength-deformation properties by the degree of saturation and pore pressure coefficient. (2) The cementation influences deformation-strength properties of volcanic cohesive soils. (3) The effects of stabilization of Oyama loam and pumice are different with both types and quantities of the additives. The Oyama pumice soils are very heterogeneous at soil particle density and water content. (4) A new engineering classification chart of volcanic cohesive soils for earthworks was proposed. 3.Volcanic-ash organic soils (1) The effects of chemical soil stabilization of Kumamoto Akaboku and Kuroboku volcanic ash soils depends on (additive amount / water content). (2) Though Aomori Kuroboku was a coarse grain than Oyama Kuroboku, the compressibility was almost same Oyama Kuroboku.
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