2001 Fiscal Year Final Research Report Summary
PHISICAL PROPERTLES OF FLUIDIZED SOIL AND PREDICTION OF LIQUEFIED GROUND DEFORMATION
| Project/Area Number |
12650500
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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 |
Geotechnical engineering
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| Research Institution | FUKUYAMA UNIVERSITY |
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Principal Investigator |
SHIBATA Toru FUKUYAMA UNIVERSITY,ENGINEERING, PROFESSOR, 工学部, 教授 (20027212)
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| Co-Investigator(Kenkyū-buntansha) |
UZUOKA Ryousuke EARTHQUAKE DISASTER MITIGATION RESEARCH CENTER, RIKEN, RESEACH FELLOW, 地震防災フロンティア・研究センター, 研究員
NISHIHARA Akira FUKUYAMA UNIVERSITY, ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (90164574)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Liwuefaction / saturated sands / glass beads / expansion / Bingham-viscosity / seepage flow / lateral deformation / numerical method |
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| Research Abstract |
In a first part of the study, the expansion and viscosity characteristics were investigated on various kinds of liquefied sands and glasss beads particles. Upward seepage flow apparatus was used in order to make liquefied conditions. In a second part, an attempt was made to predict the soil behavior during liquefaction-indeuced flow by using a numerical method.
1.Expansion ratio, V/V_O, was proportional to the upward flow rate of water v and may be expressed by the equation ; V/V_O=1+δ(v-v_c), where V is liquefied volume, V_O is solid state volume, δ is the coefficient of expansion, and v_c is the flow rate at the critical hydraulic gradient. This equation is similar in the form to thermal expansion of a liquid, and v_c is considered to correspond to the melting point of a liquid.
2.(1) Rheological measurements of liquefied soil particles with the viscometer produced Bingham-type viscosity curves. (2) The viscosity coefficient η may be expressed by η∝exp(A/v), where A is constant. Because this equation and Andrade-viscosity equation are similar, the seepage water flow rate v is considerd to correspond to the temperature of a liquid.
3.The CIP (cubic interpolated pseudoparticle) based numerical scheme was modified by incorporating the Bingham viscosity. The method was used to simulate shaking table tests on a liquefied subsoil model. From the results, the numerical method was found to satisfactorily reproduce the deformation behavior of liquefied layer.
4.Bingham model was used to represent the behavior of liquefied soil. A numerical method was used to verify the similitude law for flow deformation of liquefied ground. The numerical method repreduced the tendency of the experimental results as well as the proposed si militude law very well.
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