1992 Fiscal Year Final Research Report Summary
Measurement and estimation of unsaturated moisture properties of compacted soils and its application to analyses of embankment dams.
| Project/Area Number |
03660244
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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 | Tottori University |
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Principal Investigator |
MORII Toshihiro Tottori University, Faculty of Agriculture, Research Associate, 農学部, 助手 (30231640)
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| Co-Investigator(Kenkyū-buntansha) |
HATTORI Kunio Tottori University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (00032300)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Seepage analysis / Embankment dam / Unsaturated soil / Finite element method / Laboratory experiment / Radio Isotope method / Stability of dam |
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| Research Abstract |
A numerical seepage analysis which integrates both saturated and unsaturated flows can precisely predict water movement within embankment dams. The treatment of boundary surfaces such as seepage face and ground surfaces subjected to rainfall, infiltration and evaporation is easy with this approach. The finite element mesh used in the analysis remains invariant during transient flow and numerical iterations. Using the same mesh for stress analysis, it is possible to evaluate directly the effects of seepage forces and buoyancy on stresses and stability of embankment dams.
Subjects focused in RESEARCH are to develop
1.an efficient method for measuring moisture properties of unsaturated soils, and
2.a numerical scheme for seepage and stress analysis.
A measuring equipment using small-sized pressure transducers and Radio lsotope method is designed and set up in Subject 1. Laboratory experiments show that the equipment gives reliable data. Referring to published data, modeling of unsaturated conductivity based on lrmay-type equation is discussed. In the 2nd subject, a finite element method based on the concept of effective stress is developed for seepage, stress and stability analysis of dams. The procedure is applied to evaluate stability of an earthdam during reservoiring and drawdown. Numerical results show that the stability is strongly influenced by the change of principal stresses within the dam, and that the manner of this change is governed by the distribution of body force which occurs during reservoiring and drawdown.
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