| Project/Area Number |
09450202
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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 |
Building structures/materials
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
TOKIMATSU Kohji Professor, Faculty of Engineering, Tokyo Institute of Technology, 工学部, 教授 (50134846)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥4,900,000 (Direct Cost: ¥4,900,000)
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| Keywords | Earth pressure / Coefficient of Subgrade reaction / Torsional shear test / Earthquake / Foundation / Active earth pressure / Passive earth pressure / Pile |
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| Research Abstract |
A torsion triaxial shear test system is developed with which earth pressures in between the active and passive states can be measured. The test results show that earth pressures of normally consolidated sand in between the active and passive states can be expressed in terms of the angle of internal friction of the sand and the strain rate between minor and major axial strains. Based on this finding static earth pressures in between the active and passive states are formulated by extending the theories presented by Rankine and Coulomb. Similarly, earth pressures in between the active and passive states during earthquakes are formulated and the methods to estimate dynamic earth pressures acting on buried structures and retaining walls are presented. The effectiveness of the proposed methods is confirmed based on the comparison with the results of previous studies.
To examine the earth pressures acting on embedded foundations and piles in liquefied and laterally spreading ground, pseudo-static analyses are conducted for well-documented case histories of pile foundations and the scaling factors for the horizontal subgrade reaction of piles and for the maximum reaction force are back-calculated. The analytical results show that : (1) both the coefficient of the horizontal subgrade reaction of piles and the maximum reaction force of laterally-spreading soils are 0.05-0.2 times those of non-liquefied soils, and (2) the earth pressure acting on the embedded foundation varies from the active to passive state depending on the pile rigidity and relative displacement between the embedded foundation and the surrounding ground.
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