2003 Fiscal Year Final Research Report Summary
IMPORTANCE OF SOIL DILATANCY AND 3D EFFECTS IN BRACED EXCAVATION BPROBLEMS AND ITS APPLICATION TO STRESS-DEFORMATION ANALYSIS
| Project/Area Number |
14350257
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
NAKAI Teruo Nagoya Institute of Technology, Faculty of Engineering, Professor, 工学研究科, 教授 (00110263)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Kenichi Nagoya Institute of Technology, Faculty of Engineering, Assoc.Professor, 工学研究科, 助教授 (50271648)
HINOKIO Masaya Nagoya Institute of Technology, Faculty of Engineering, Research Assoc., 工学研究科, 助手 (00335093)
ZHANG Feng Nagoya Institute of Technology, Faculty of Engineering, Professor, 工学研究科, 教授 (70303691)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Braced excavation / Construction sequnce / FEM / 3D effects / Constitutive model for soils / Model tests / Numerical Analysis |
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| Research Abstract |
How to predict the surface settlements of the ground and how to evaluate the earth pressure on the braced wall are serious problems at open excavation in urban area. However, in the present practical methods, the earth pressure is usually predicted by conventional methods such as a frame model together with Rankine's earth pressure theory. There is also no appropriate method to predict the surface settlements of ground-usually empirical method and/or elastic finite element method are commonly used. In addition to this, finite element analysis is usually carried out assuming two-dimensional condition such as plane strain condition. The ground movements and earth pressure are much influenced by the construction sequence including three-dimensional effect, which are not considered in these conventional methods.
This research has been carried out to investigate the ground movements and the earth pressures during braced excavation and devise proper and economic open excavation methods in urban area. For this purpose, we carried out elastoplastic finite element analyses in which the mechanical behavior of soils, structures and interface between soil and structure are properly taken into consideration, together with the corresponding model tests. Main contents of the present research can be summarized as follows :
●Investigate the influence of the stiffness of wall and strut on surface settlements and earth pressure due to braced excavation
●Investigate the influence of excavation sequence (including the arrangement of struts) on the surface settlements and earth pressure.
●Verify the usefulness of a newly proposed exaction method, in which no strut is used in excavation and temporary retaining wall is used as a part of permanent structure.
●Characterize three-dimensional effects of tunnel excavation on surface settlements and earth pressure.
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