1998 Fiscal Year Final Research Report Summary
Damage Evaluation System of Soils in Subsurface Layers of Ground Using Identification Method
| Project/Area Number |
09650529
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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 |
構造工学・地震工学
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| Research Institution | University of Tokushima |
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Principal Investigator |
SAWADA Tsutomu University of Tokushima, Faculty of Engineering, Professor, 工学部, 教授 (20035645)
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| Co-Investigator(Kenkyū-buntansha) |
TSUJIHARA Osamu Wakayama National College of Technology, Associate Professor, 助教授 (50188546)
NARIYUKI Yoshifumi University of TokushiTna, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20127848)
SUGITO Masata Uuiversity of Gifu, Faculty of Engineering, Professor, 工学部, 教授 (60115863)
HIRAO Kiyoshi University of Tokushima, Faculty of Engineehng, Professor, 工学部, 教授 (00035619)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Damage of Soils / Identification / Shear Strain / Vertical Array Records / S-wave Velocity / Quality Factor / Frequency Dependency |
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| Research Abstract |
The objective of this study is to present a system program for evaluating the earthquake damage of soils in sedimentary layers of ground, in which identification method and calculation of shear strain are connected. In this study, a new model of frequency-dependent quality factor in sedimentary layers, Q(f), is presented as follows.
Q(f) = Qo / (1 + a exp(-b(f-fo)^2))
where Qo, a, b and fo are the parameters which prescribe the frequency-dependency of quality factor, and f is frequency. The model of quality factor is introduced into identification program for S-wave velocity and quality factor of each layer in subsurface ground.
The results in this study are summarized as follows.
1. The identification program, which was used previously, has been improved, in order to consider the frequency dependency of quality factor of each layer in subsurface ground.
2. The program has been developed for calculating the shear strain in each layer of subsurface ground, using the S-wave velocity and quality factor identified from vertical array records. The system program for evaluating the earthquake damage of soils in each layer has been constructed by connecting the identification program and the program for calculating shear strain.
3. The numerical analyses are carried out using vertical array records at 9 sites in Japan, which show that the maximum shear strain is about 5_x10^<-4> in soft soil, where the maximum acceleration of record is 100cm/sec^2.
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