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Unsaturated Mechanical Properties of Shirasu

Research Project

Project/Area Number 16580200
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Irrigation, drainage and rural engineering/Rural planning
Research InstitutionKagoshima University

Principal Investigator

HIYAMA Hiroki  Kagoshima University, Agriculture, Associate Professor, 農学部, 助教授 (10208788)

Co-Investigator(Kenkyū-buntansha) HIRA Mizuki  Kagoshima University, Agriculture, Research Associate, 農学部, 助手 (40284913)
Project Period (FY) 2004 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000)
KeywordsShirasu / unsaturated soil / collapse / soaking / suction / 強度・変形特性
Research Abstract

Shirasu is the pyroclastic flow deposit distributed in the southern part of Kyushu. Shirasu sites are prone to natural disasters, like slope failure and debris flow, because Shirasu has a smaller density of soil particles and a keen erosivity. The above natural disasters occur with increasing the degree of saturation by rainfall. It is therefore necessary to investigate the mechanical properties of Shirasu on the process from dry to wet condition. In order to examine the effect of a change in saturation on the compressibility and shear strength properties, three types of tests were carried out on compacted Shirasu. The following results were obtained.
1. From the results of one dimensional compression tests, the soil settles due to soaking during the test. It is the phenomenon called collapse. The compression curves of compacted soils fall to the nearby void ratio of the initially soaked soil compressed under same stress. The Incidence of collapse is the highest when the compression stress is slightly higher than the compression yield stress.
2. From the results of direct shear tests, the shear strength of compacted Shirasu decreases to that of the initially soaked soil due to soaking during the process on shearing. The incidence of collapse increases while density or normal stress of the specimen decreases. The degree of saturation affects the cohesion of strength parameters, but it is not related to the internal friction angle.
3. From the results of unsaturated triaxial compression tests, suction and confining stress, respectively, affect a change in water content and density.

Report

(4 results)
  • 2006 Annual Research Report   Final Research Report Summary
  • 2005 Annual Research Report
  • 2004 Annual Research Report

Research Products

(10 results)

All 2007 2006 2005 2004

All Journal Article

  • [Journal Article] 2006年7月鹿児島県北部集中豪雨による農地災害について2007

    • Author(s)
      平 瑞樹, 肥山浩樹, 高木 東
    • Journal Title

      自然災害研究協議会西部地区部会報・研究論文集 31

      Pages: 37-40

    • NAID

      40015838932

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Farmland damages by a torrential rain at the northern part of Kagoshima in July 2006.2007

    • Author(s)
      Mizuki Hira, Hiroki Hiyama, Azuma Takagi
    • Journal Title

      Western Regional Division Report of Natural Disaster Research Council 31

      Pages: 37-40

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] 鹿児島県北部集中豪雨による農地被害2007

    • Author(s)
      平 瑞樹, 肥山浩樹, 高木 東
    • Journal Title

      自然災害研究協議会西部地区部会報・研究論文集 28

      Pages: 133-136

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Deformation Behavior of Shirasu Soil by the Extended Subloading Surface Model2006

    • Author(s)
      Mizuki Hira, K.Hashiguchi, M.Ueno, T.Okayasu
    • Journal Title

      Lowland Technology International 8(1)

      Pages: 37-46

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Deformation Behavior of Shirasu Soil by the Extended Subloading Surface Model.2006

    • Author(s)
      Mizuki Hira, K.Hashiguchi, M.Ueno, T.Okayasu
    • Journal Title

      Lowland Technology International 8(1)

      Pages: 37-46

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Deformation Behavior of Shirasu Soil by the Extended Subloading Surface Model2006

    • Author(s)
      M.Hira, K.Hashiguchi, M.Ueno, T.Okayasu
    • Journal Title

      Lowland Technology International 8(1)

      Pages: 37-46

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Elastoplastic Constitutive Equation of Volcanic Sandy Soil "Shirasu" Based on the Subloading Surface Model2005

    • Author(s)
      Mizuki Hira, K.Hashiguchi, T.Okayasu
    • Journal Title

      Proceeding of the Eleventh International Symposium on Plasticity and its Current Applications

      Pages: 262-264

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Elastoplastic Constitutive Equation of Volcanic Sandy Soil "Shirasu" Based on the Subloading Surface Model.2005

    • Author(s)
      Mizuki Hira, K.Hashiguchi, T.Okayasu
    • Journal Title

      Proceeding of the Eleventh International Symposium on Plasticity and its Current Applications

      Pages: 262-264

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] 肥薩地方の集中豪雨による農地被害2004

    • Author(s)
      平 瑞樹, 肥山浩樹, 長 勝史
    • Journal Title

      自然災害研究協議会西部地区部会報・研究論文集 28

      Pages: 133-136

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Farmland damages by a torrential rain in Hisatsu region of Kyushu.2004

    • Author(s)
      Mizuki Hira, Hiroki Hiyama, Katsushi Cho
    • Journal Title

      Western Regional Division Report of Natural Disaster Research Council 28

      Pages: 133-136

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary

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Published: 2004-03-31   Modified: 2016-04-21  

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