1998 Fiscal Year Final Research Report Summary
A Study on Limit State Design of Ground Structures by Dilatational Strain Energy
| Project/Area Number |
08455208
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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 |
構造工学・地震工学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
NISHIOKA Takashi Institute of Engineering, University of Tsukuba Mechanics, 構造工学系, 教授 (30011141)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Yasuo Institute of Engineering, University of Tsukuba Mechanics, 構造工学系, 教授 (90111476)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Limit Seismic Intensity / Ground Structures / Stability of the Ground / Mean Stress / Internal Friction Angle / Cohesion / Earthquake Reistance of the ground / Drucker-Pragar's Yield Condition |
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| Research Abstract |
The purpose of this paper is to make clear the ground stability around tunnel structures in earthquake by using dilatational elastic strain energy generated in the ground and to find proper index for earthquake resistance of the ground around tunnel structures.
In Chapter 1, the stability of earth materials under plane strain condition is discussed by using dilatational elastic strain energy When dilatational elastic strain energy in the ground reaches its maximum defined by cohesion, internal friction angle and mean stress of the ground, shear zone spreads in the ground. The direction of shear zone is decided by the dilatational angle and internal friction angle of the ground.
In Chapter 2 and 3, the earthquake resistance of the ground around the box tunnel and shield tunnel is discussed by quasi-static analysis of elasto-plastic finite element method. Limit Seismic Intensity is defined as the time when shear zone connects between ground surface and upper parts of tunnels, as the seismic intensity increases. Aocording to FEM calculation, it is shown that LSI depends on cohesion, internal friction angle and mean stress of the ground.
In Chapter 4, dynamic response calculation in earthquake shows that LSI is the good index for earthquake resistance design of the ground around structures, because DSI shows the largest intensity of the ground than in dynamic response calculation.
The Chapter 5 is the conclusion.
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