2005 Fiscal Year Final Research Report Summary
Development of retrofit method for existence pile foundations considering effects of embedment of footing
| Project/Area Number |
16560495
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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 |
Building structures/materials
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TAMURA Shuji Kyoto University, DPRI, Associate Professor, 防災研究所, 助教授 (40313837)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Pile foundation / Embedded footing / Seismic earth pressure / Friction / Dynamic interaction / Liquefaction / Centrifuge test / Retrofit |
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| Research Abstract |
To develop the retrofit method for existence pile foundations, the effects of earth pressure and friction acting on an embedded footing on pile stress were investigated based on large-scale shaking table tests and centrifuge tests. The following conclusions are drawn :
(1) The total earth pressure in the non-liquefaction tests tends to be out of phase by 180 degrees with the superstructure inertia, reducing the shear force and bending moment at the pile head.
(2) The total earth pressure in the liquefaction tests tends to be in phase with the superstructure inertia, making the bending moment at the pile head large. A method for estimating the total earth pressure considering its phase relative to the superstructure inertia as well as the effects of soil inertia has been proposed. The proposed method gives a reasonable explanation of the difference in earth pressure between different tests.
(3) The total earth pressure in the liquefaction tests tends to increase, when the excess pore water pressure in the liquefied soil decreases.
(4) The maximum amplitude of the total earth pressure in dense dry sand is about 1.5 times as large as that in loose dry sand. The maximum amplitude of the sidewall fiction in dense dry sand is about 1.2 times as large as that in loose dry sand.
(5) The damping factors of the total earth pressure and sidewall fiction in dense sand are smaller than those in loose sand.
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Research Products
(12 results)
