Development of Method for Estimating Lateral Resistance of Pile Groups in Liquefied Soil during an Earthquake
| Project/Area Number |
14550569
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TOMINAGA Koji Hiroshima University, Graduate School for International Development and Cooperation, Professor, 大学院・国際協力研究科, 教授 (10067720)
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| Co-Investigator(Kenkyū-buntansha) |
徐 挺 広島大学, 大学院・国際協力研究科, 助手 (70274131)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Effective stress in Soil / Lateral resistance of single pile / Lateral resistance of pile group / Space of piles / Number of piles / Coefficient of lateral soil reaction / Plastic lateral soil reaction / Liquefaction / 群杭の水平抵抗 / 群杭水平抵抗 / 初期水平抵抗剛性 / 最大杭頭せん断力 / 水平地盤反力分布 / 載荷速度 / 終局水平抵抗力 / 群杭効率 |
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| Research Abstract |
The mechanism of the liquefaction in saturated sand and soil resistance during an earthquake has been gradually made clear since 1964 when the Niigata earthquake occurred. In recent years, however, the damages due to the liquefaction caused by the large earthquakes have been reported, for example the Hokkaido-nansei-oki earthquake in 1993, the Hyogoken-nambu earthquake in 1995, the Tottori-seibu earthquake in 2000, and so on. In the Hyogoken-nambu earthquake, the large-scale liquefaction occurred in the wide area from the former coastline to the reclaimed land, and the damages occurred in the pile foundation under buildings. The cause of damages of the pile foundations has investigated by some researchers. However, many uncertainties to establish the design method for laterally loaded piles supporting a building still remain, especially when considering effective stress reduction in soil around piles due to pore water pressure increasing during an earthquake. Therefore, we devised and
… More
made the appropriate test apparatus for decreasing effective stress in the test sand bed by using the seepage flow, and performed laterally loading tests in order to investigate the subgrade reaction acting on the model pile.
The following points are found out from these studies :
1.The lateral subgrade reaction on the pile at a given level is approximated by the hyperbola with respect to the lateral displacement of the pile. Then the initial modulus and the convergence of the hyperbola are related to the initial coefficient of the lateral subgrade reaction and the ultimate lateral subgrade reaction, respectively.
2.Both of the initial coefficient of lateral subgrade reaction and the ultimate value increase linearly with depth (i.e. triangle distribution), and decrease linearly with decreasing the effective stress in the sand bed. From these results, we are able to present the new design method of pile foundations on the basis of the subgread reaction analysis which considers the reduction of effective stress in ground during an earthquake.
3.Furthermore, the analysis for the pile group foundation based on the three dimensional theory, which considers an elasto-plastic continuum and the ultimate lateral resistance of the soil around the piles, is also proposed. Less
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Report
(4 results)
Research Products
(23 results)
