1998 Fiscal Year Final Research Report Summary
Cyclic behavior of clay during great earthquake and its consititutive model
| Project/Area Number |
09650545
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
OKA Fusao Kyoto University, Civil Engg., Professor, 工学研究科, 教授 (10111923)
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| Project Period (FY) |
1997 – 1998
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| Keywords | constitutive model / viscoplasticity / viscoelasticity / liquefaction / earthquake / kinematic hardening / cohesive soil / cyclic loading |
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| Research Abstract |
Liquefaction has been recognized as an important factor of ground damage due to 1995 Hyogoken Nambu Earthquake. It is well known that soft clay sediment are deposited around Japanese urban area such as Osaka city. In order to accurately clarify the ability of the earthquake resistance of ground, it is necessary to clarify the dynamic behavior of soft clay deposit due to the great earthquake such as Hyogoken Nambu Earthquake which is magnitude 7 in Richter scale.
For this reason, the present study focuses on the modeling of dynamic behavior of clay. The model proposed is applicable to the behaviors both at small strain around 1% and at the large strain more than 10%. For this purpose, cyclic triaxial and torsional tests have been performed on clay. Based on the experimental results, a cyclic viscoplastic constitutive model has been developed using the non-linear kinematic hardening rule. In the study, a viscoelastic- viscoplastic model has been newly proposed in order to describe energy dissipation chracteristics in high frequency domain at a small strain. Finally, by the one-dimensional simulation with the observed acceleration records at Port Island during the 1995 Hyogoken-Nambu Earthquake, the effect of viscoelastic and viscoplastic property of clay on the of dynamic behavior of ground including clay layers is studied.
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