1996 Fiscal Year Final Research Report Summary
An investigation on effects of countermeasures against liquefaction of sand deposits with structures
| Project/Area Number |
07555445
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Tokyo Institue of Technoloty |
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Principal Investigator |
TAKEMURA Jiro Tokyo Inst.of Tech., Faculty of Eng., Assosiate Prof., 工学部, 助教授 (40179669)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUDA Takashi Ohbayashi-gumi, Technology Research Center, Vice-senior Researcher, 技術研究所, 副主任研究員
KOUDA Masayuki Tokyo Inst.of Tech., Faculty of Eng., Research Associate, 工学部, 助手 (10282823)
OKAMUEA Mitsu Tokyo Inst.of Tech., Faculty of Eng., Research Associate, 工学部, 助手 (50251624)
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| Project Period (FY) |
1995 – 1996
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| Keywords | liquefaction / sand / oil tank / embankment / model test / sheet pile wall / gravel drain / settlement |
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| Research Abstract |
Centrifuge model tests are carried out to study the effect of various countermeasures against liquefaction of sand deposits with an undergrond structure and a structure on surface. Model tests are conduced on five types of models ; one without any countermeasures and four with countermeasures ; sheet pile walls with or without drainage capability, sheet pile walls of which tops are tied with rods and gravel drains.
Following conludsions are drawn from this study.
1.For foundation soil with an underground structure, upward movements of it take place when excess pore pressure beneath the structure reaches a threshold value. In countermeasures to prevent the upward movement, an attempt should be made to keep the excess pore pressure lower than this threshold.
2.Responses of acceleration of structures depend very much on the excess pore pressures generated in foundation soil. The acceleration responses at the very early stages of input motons are similar for all the cases, but the subsequcnt responsese differ for different types of countermeasure. For the cases without drainage, the acceliration of structure decreases with the generation of excess pore pressure. On the other hand, for the cases with drainage, the acceleration of structure increase.
3.Settlements of structures on a ground surface like oil tank and embankment arise from two reasons ; the compression of sand beneath due to consolidation and the other the lateral movement of hte sand. Increase of lateral movement gives rise to an increase in total settlements of the structure, suppression of lateral spreading is necessary.
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