| Project/Area Number |
12450188
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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 | Kanazawa University |
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Principal Investigator |
MATSUMOTO Tatsunori Kanazawa University, Dept. of Civil Eng., Prof., 工学部, 教授 (10143877)
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| Co-Investigator(Kenkyū-buntansha) |
KITAURA Masaru Kanazawa University, Dept. of Civil Eng., Prof., 工学部, 教授 (70026269)
MIURA Kinya Toyohashi Technical College, Dept. of Civil Eng., Assoc. Prof., 建設工学系, 助教授 (40190582)
HORIKOSHI Kenichi Taisei Corporation, Technology Center, Senior Researcher, 技術センター・土木技術研究所, 副課長(研究職)
TAKAHARA Toshiyuki Kanazawa University, Dept. of Civil Eng., Research Assit., 自然科学研究科, 助手 (20324098)
WANG Fawu Kanazawa University, Dept. of Civil Eng., Assoc. Prof., 工学部, 講師 (10324097)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥11,000,000 (Direct Cost: ¥11,000,000)
Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2001: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2000: ¥6,400,000 (Direct Cost: ¥6,400,000)
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| Keywords | Piled raft / Pile / Centrifuge modeling / Laboratory model test / Horizontal resistance / Earthquake-proof / Sand / Deformation analysis |
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| Research Abstract |
The main objectives of this research are 1) provide comprehensive experimental data for pile rafts subjected to static horizontal loads and dynamic (seismic) loads for design of piled raft foundations, 2) develop a simple but workable analytical method for deformation and load proportion of pile rafts and pile groups. To achieve these objectives, a series of centrifuge modeling of pile rafts was extensively conducted and some conclusions are shown below:
1. The stiffness and the ultimate resistance of the single pile in the piled raft are highly different from those observed in the loading test of the isolated single pile. The increase in the confining stress around the pile due to the load transferred through the raft base should be considered in the evaluation of the pile response in the piled raft design, as well as the interaction effects between the components.
2. The ultimate frictional resistance of the raft component in the piled raft was smaller (rigid pile head connection) or a
… More
lmost the same (hinged pile head connection) compared with the estimates from the raft vertical loads and the coefficient of the friction between the raft base and the soil. It was thought that the soil beneath the raft was constrained by the piles which may reduce the shear deformation of the soil just beneath the raft base, and thus the mobilized shear stress at the interface was smaller.
3. As for the proportion of the horizontal load carried by each component, the raft initially carried more load than the piles, with larger displacements the piles more than the raft in the piled raft with rigid pile head connection. In the piled raft with hinged pile head connection, the contribution of the piles was much smaller. Overall, however, the proportion is highly dependent on the piled raft displacement, and it is therefore important to consider such non-linear response in the designs of piled raft foundations.
4. In the piled raft designs, evaluation of the displacement (settlement, horizontal displacement, and inclination) and the proportion of the load carried by the components are the most important factors. The dynamic behaviors of the above factors were intensively examined in this paper.
5. The change in the vertical load sharing between the piles and the raft base was relatively small compared with the horizontal load, even when the piled rafts were subjected to relatively strong input motion. Less
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