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Evaluation of deformation and strength characteristics of sand deposits during earthquakes based on in situ frozen samples

Research Project

Project/Area Number 60460172
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Building structures/materials
Research InstitutionTokyo Institute of Technology

Principal Investigator

YOSHIMI Yoshiaki  Professor, Tokyo Institute of Technology, 工学部, 教授 (90016329)

Co-Investigator(Kenkyū-buntansha) TOKIMATSU Kohji  Associate Professor, Tokyo Institute of Technology, 工学部, 助教授 (50134846)
Project Period (FY) 1985 – 1986
Project Status Completed (Fiscal Year 1986)
Budget Amount *help
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1986: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1985: ¥3,800,000 (Direct Cost: ¥3,800,000)
KeywordsSand / Liquafaction / Sampling by in situ freezing / Tube sampling / Shear modulus / N-value / Undrained shear strength / Drained shear strength / Sample disturbance / Deformation characteristics / Dilatancy
Research Abstract

Laboratoty tests were conducted on samples obtained from sand deposits having different SPT N-values by an in situ freezing method and by an ordinary tube sampling method. Based on the in situ frozen samples, it was observed that (1) the undrained shear strength of saturated sands having the same relative density could vary widely depending on the method and time of deposition of the sand, but (2) a good correlation existed between the undrained shear strength and the SPT N-values corrected for confining stress. The in situ liquefaction resistance of the sands predicted from the laboratoty test results were compatible with the values based on the case histories of liquefaction in the field.
Comparison of the test results of the in situ frozen samples and the tube samples revealed that (1) the static drained strength of the two did not differ much; (2) the undrained shear strengths of the tube samples were considerably lower than those of the in situ frozen samples, the difference being more pronounced as the density increased; and (3) the difference was due to the change in the negative dilatancy characteristics of the sands during sampling.
Additional tests conducted to study the cause of sample disturbance showed that (1) the reduction in the undrained shear strength was mainly caused by shear strain history during sampling, rather than by the release of confining stresses after sampling, (2) the undrained shear strength could markedly be reduced due to shear strain history even when the change in density was negligible, and (3) a good correlation existed between undrained shear strength and shear modulus, suggesting the possibility of evaluating the quality of sand samples on the basis of shear modulus.

Report

(1 results)
  • 1986 Final Research Report Summary
  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] 時松孝次: 土質工学会論文報告集. 26. 53-64 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] 時松孝次: 昭和60年度サンプリングシンポジウム発表論文集. 29-32 (1985)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] 保坂吉則: 第21回土質工学研究発表会. 569-570 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] 片山幾夫: 第21回土質工学研究発表会. 583-584 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] 保坂吉則: 第22回土質工学研究発表会. 予定. (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Kohji Tokimatsu: "Effects of sample disturbance on dynamic properties of sand" Soils and Foundations. 26. 53-64 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Kohji Tokimatsu: "Evaluation of sample quality by elastic shear modulus" Proc. Sampling Symposium. 29-32 (1985)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Yoshinori Hosaka: "Effects of sample disturbance on liquefaction resistance of sand" Proc. 21th Annual Meeting of JSSMFE. 569-570 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Ikuo Katayama: "Comparison of dynamic soil properties between undisturbed and disturbed dense sand samples" Proc. 21th Annual Meeting of JSSMFE. 583-584 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Yoshinori Hosaka: "Relationship between SPT N-value and liquefaction potential of sands by in situ freezing" Proc. 22th Annual Meeting of JSSMFE. (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary

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Published: 1987-03-31   Modified: 2016-04-21  

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