| Project/Area Number |
04660254
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
農業土木
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| Research Institution | Okayama University |
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Principal Investigator |
FUJII Hiroaki Okayama Univ., Fac.of Env.Sci.Tech., Prof., 環境理工学部, 教授 (70033264)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Shinichi Okayama Univ., Fac.of Env.Sci.Tech., Lecturer, 環境理工学部, 講師 (30198501)
SHIMADA Kiyoshi Okayama Univ., Fac.of Env.Sci.Tech., Assoc.Prof., 環境理工学部, 助教授 (20123234)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1992: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Soft ground / Consolidation / Settlements / Pore pressure / Lateral displacement / Finite Element Method / Field Measurement |
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| Research Abstract |
Finite Element Method is applied to the consolidation analysis for the soft grounds of five projects in reclaimed lands of Kojima and Kasaoka Bay Area.The soft grounds were improved with card-board drain, packed-sand drain and sand compaction pile method. Installed were field instruments for measuring settlements, lateral displacements and pore water pressure. The analyzes were carried out under the condition of the plane strain and axi-symmetric analysis. Soil parameters for the analyzes, i.e., Young's modulus, Poisson's ratio and coefficient of permeability are determined from the standard consolidation tests and Plasticity index. The following conclusions are obtained from the comparison between observed data and calculated results.
1) The method presented herein can predict the settlements of the soft grounds improved with three different methods. While the axi-symmetric analysis gives the better estimation to the observed value of the grounds improved with card-board and packed sand drains, the analysis giving the prescribed displacements for the ground improved with the sand compaction piles method show that the trend of observed and calculated settlements are similar.
2) The starting time of secondary consolidation and the coefficient of secondary consolidation can be obtained from the back analysis using observed settlements.
3) The degrec of estimation difference (D_<ED>) for pore pressures increases with X/L,where X is the distance of the measuring point from the fringe of the embankment and L is the width of the embankment. However, The rate of change of D_<ED> does not change. Both D_<ED> and the rate of the degree of D_<ED> increases with X/L.
4) D_<ED> in the middle of embankments shows the lower value ranged from 0.5% to 24%.
5) D_<ED> in the small embankment area is big, but the rate of change of D_<ED> is almost zero. However, D_<ED> and the rate of change of D_<ED> in the wide embankment area indicates small value.
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