| Project/Area Number |
09650553
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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 | Yamaguchi University |
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Principal Investigator |
HYODO Masayuki Faculty of Engineering, Yamaguchi University Professor, 工学部, 教授 (40130091)
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| Co-Investigator(Kenkyū-buntansha) |
NAKATA Yukio Faculty of Engineering, Yamaguchi University Associate Professor, 工学部, 助教授 (90274183)
MURATA Hidekazu Faculty of Engineering, Yamaguchi University Professor, 工学部, 教授 (80044618)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | marine clay / aging effect / cyclic shear strength / overconsolidated / rate effect / undisturbed sample / earthquake / cyclic triaxial test / 動的強度 / 塑性指数 / 疑似過圧密 / 初期せん断応力 / 周波数 / 繰越し三軸試験 / 載荷周波数 / 過圧蜜 |
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| Research Abstract |
For the purpose of this research programme, undisturbed clay samples were taken from alluvial deposits at seven different urban coastal locations in Japan. At several of the Locations samples were taken from many different depths in order to sample different sedimentary environments. The samples were then testes in both undisturbed and remoulded states. A testing programme was devised to separately examine the influence of plasticity index, aging factors, rate effect and overconsolidation ratio on the undrained cyclic stength of the clays. The cyclic data for the normally consolidated samples was used empirically to define the cyclic strength of the clays as an intrinsic function of the plasticity index IィイD2pィエD2. This was then modified taking into account the vertical yield stress ratio σィイD2vyィエD2'/σィイD2voィエD2', degree of aging and geological OCR. The cyclic strength of anisotropically consolidated clays at low initial drained shear stress ratios increased with decreasing plasticity. This reversed as the drained shear stress ratio increased. It was possible to define a simple function for the cyclic strength normalised by the isotropic cyclic strength RィイD2ISOィエD2 against the initial drained shear stress ratio. This function was shown to be dependent on plasticity index IィイD2pィエD2 but stress history.
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