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2002 Fiscal Year Final Research Report Summary

Method for making homogeneous unsaturated soil specimens with distinct stress histories and their deformation and strength characteristics

Research Project

Project/Area Number 13650539
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Geotechnical engineering
Research InstitutionShinshu University

Principal Investigator

KONISHI Junichi  Shinshu University, the department of technology, assistant professor, 工学部, 助教授 (60021002)

Project Period (FY) 2001 – 2002
Keywordsunsaturated soils / suction / method of making specimens / shear strength / triaxial test / unconfined compression test / water retention characteristics
Research Abstract

A technique for making unsaturated soil samples using pressure membrane method are developed. Advantages and limitations of this method are discussed. The membrane filter selected and used is a cellulose acetate type filter of 0.2 μm pore size and of 0.125 μm thick. The air entry value of the filter is 24kPa.
For a pressure range more than the air entry value of the filter, the water retention curves for dehydration obtained by the pressure membrane method seem to coincide with those obtained by pressure plate method.
In the pressure membrane method, only small absorption occurs when the applied pressure is released. This property may enable us to make samples without absorption of water even when the pressure is released.
The pressure membrane method is better than the compaction method for making a loose sample.
Initial suction of the trimmed specimens is lower than the applied pore air pressure when the samples are made by the pressure membrane method. To make samples with a suction, higher pore air pressure than the suction should be applied.
Triaxial compression tests under constant pore air pressure in undrained condition were carried out for unsaturated soil. The suction may have a quasi-overconsolidated effect on the saturated samples with the suction histories.
The apparent cohesion increase proportionally with suction, whereas the internal friction angle seems to have a constant value since the inclination of the failure line does not change with the air pressure value and the higher the air pressure, the larger the intercept of the failure line.
In unconfined compression tests of unsaturated soils, volume change may occur. Higher the suction of the specimen, the higher the dilation of it.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Ando, K, Konishi, J., Toyoda, T., Tanahashi, H.: "A technique for making unsaturated samples using membrane filters"Clay Science for Engineering, Adachi & Fukue (eds), Proc.IS-Shizuoka, Balkema. 149-154 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 安藤幸二, 山本将士, 小西純一, 豊田冨晴: "不飽和土の一軸圧縮変形・強度特性"地盤工学研究発表会. 36. 893-894 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 橋本幸樹, 安藤幸二, 岡田竜太, 小西純一, 豊田冨晴: "不飽和まさ土の一軸圧縮せん断特性"地盤工学研究発表会. 37. 929-930 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 山口大樹, 安藤幸二, 小西貴士, 小西純一, 豊田冨晴: "種々のサクション履歴を有する不飽和士の強度特性"地盤工学研究発表会. 37. 933-934 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 小西貴士, 山口大樹, 安藤幸二, 小西純一, 豊田冨晴: "水浸飽和供試体の圧密排気非排水せん断強度"土木学会中部支部平成14年度研究発表会. 267-268 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ando, K., Konishi, J., Toyoda, T., Konishi, T, Yamaguchi, H.: "Effect of suction and suction histories on the strength and Deformation characteristics of silty soils"Proc.UNSAT-Asia2003/. (2003年4月大阪で開催予定がSARSのため11月に延期された・原稿受理印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ando, K., Konishi, J., Toyoda, T., Tanahashi, H.: "A technique for making unsaturated samples using membrane filters"Clay Science for Engineering, Adachi & Fukue(eds), Proc.IS-Shizuoka, Balkema. 149-154 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ando, K., Konishi, J., Toyoda, T., Konishi, T., Yamaguchi, H.: "Effects of suction and suction histories on the strength and Deformation characteristics of silty soils"Proc. UNSAT-Asia 2003. (postponed until Nov.2003)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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