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Experimental Study on Stress Corrosion and Vacuum Effect of Rocks

Research Project

Project/Area Number 06452360
Research Category

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

Allocation TypeSingle-year Grants
Research Field 資源開発工学
Research InstitutionKumamoto University

Principal Investigator

OKAMURA Hiroshi  Kumamoto University, Faculty of Engineering, Professor, 工学部, 教授 (40040373)

Co-Investigator(Kenkyū-buntansha) OBARA Yuzo  Kumamoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50135315)
SUGAWARA Katsuhiro  Kumamoto University, Faculty of Engineering, Professor, 工学部, 教授 (60109668)
中山 智晴  熊本大学, 工学部, 助手 (70207950)
Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1994: ¥6,200,000 (Direct Cost: ¥6,200,000)
KeywordsRocks / Uniaxial Compression Test / Stress Corrosion / Vacuum Effect / Water Vapor Pressure / Strength of Rocks / 地層処分 / 天然バリア / マルチクラック / クリープ強度
Research Abstract

At the beginning of the twenty one century, the large rock cavern for radioactive waste diaposal will be constructed within a rock mass at a depth of more than 1000m, in Japan. The stability of such large rock cavern must be guarantee over very long timescale. The prediction of long-term strength of rocks is indispensable for insuring long-term stability of the rock cavern.
The strength of rocks under compression is affected by the density, the shape and the direction of cracks, the strain and stress rate of loading, the stress state , the temperature and the existence of water in vapor phase or in liquid phase, and so on. Some researchers have inducated that the strength of rocks in dependent on the subcritical crack growth due to stress corrosion and is proportional to the water vapor pressure in atmosphere. However, few experiments to verify this fact have been performed.
In this research, to examine the influence of the water as the stress corrosion agent on the strength of rocks, a … More series of uniaxial compression tests under the water vapor pressure ranging from 10^<-3> to 10^3 Pa is conducted on Kitagishima granite and Kumamoto andesite. Furthermore, the stress corrosion index is determined, then the estimation of long-teem strength of rock is discussed. The main results obtained are follows :
1.The elastic modulus are not affected by the stress corrosion due to water vapor, analyzing the stress strain curve obtained.
2.The uniaxial compressive strength of both rocks increases with decreasing water vapor pressure. It is clarified that this effect is dependent on the stress corrosion.
3.The values of the stress corrosion index obtained from the results are 36 in Kumamoto andesite and 61 in Kitagishima granite, based on the relation between uniaxial compressive strength and water vapor pressure. The linear relation is applicable to the range of water vapor pressure 10^<-3> to 10^3 Pa.
4.The estimation of long-term strength of rock is discussed. The discover of an agent activating the stress corrosion is indispensable to estimate the long-term stability of rock cavern. Less

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] Y.OBARA, K.SUGAWARA: "Influence of water vapor pressure on strength of rocks under uniaxial compression" Proceedings of North American Rock Medianics Symposium. (to be appeared). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Y.Obara, K.Sugawara and N.Tokashiki: "Influence of water vapor pressure on strength of rocks under uniaxial compression." Proc.of NARMS'96. (to be appeared). (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Y.OBARA,K.SUGAWARA: "Influence of water vapor pressure on strength of rocks under uniaxial compression" Proceedings of North American Rock Medranics Symposium. (to be appeared). (1996)

    • Related Report
      1995 Annual Research Report
  • [Publications] 坂口清敏: "コンパクトオーバーコアリング法による岩盤応力の測定" 資源・素材学会誌. 110. 331-336 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 坂口清敏: "岩盤応力測定のための応力開放プロセスシミュレーション" 資源・素材学会誌. 110. 601-606 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] Yuzo Obara: "Rock stress measurement by stress relieving in Japan" Proc.of MMIJ/AusIMM Joint Symposium. 425-432 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 金子勝比古: "鉱山微小地震とその解釈" 物理探査データの画像化による総合解釈シンポジウム論文集. 15-20 (1994)

    • Related Report
      1994 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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