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Mechanisms of bedrock frost shattering and associated rockfall generation

Research Project

Project/Area Number 06680157
Research Category

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

Allocation TypeSingle-year Grants
Research Field 自然地理学
Research InstitutionUniversity of Tsukuba

Principal Investigator

MATSUOKA Norikazu  Institute of Geoscience, University of Tsukuba Assistant professor, 地球科学系, 講師 (10209512)

Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
KeywordsPeriglacial / Weathering / Mass movement / Freeze-thaw / Frost shattering / Rockfall / Field measurement / Mountain
Research Abstract

Frost shattering of rockwalls and resulting rockfall activity were studied in a Japanese high mountain environment by means of (1) a laboratory experiment of freezing expansion of a fractured rock sample, (2) field measurements of rock joint opening due to freezing, and (3) observations of rockfall activity from a cirque backwall. Distribution, trail and dimensions of all rock blocks fallen on snow were investigated at 1-10 day intervals during snow-melting seasons. Electric sensors connected to data loggers permitted continuous recording of separation of rock joints and rock temperatures for two years. In the laboratory, monitoring was made of freezing expansion of a fractured granite block and rock temperatures.
Field measurements revealed two events of rock joint opening, one in midwinter and the other in early melting season. Both indicated that opening occurred when a water-filled joint was refrozen following temporary melting which allowed water to percolate into the joint. The laboratory study showed that freezing expansion was completed before the rock temperature was fallen below -2゚C.These results suggest that rock joints tend to open at a little lower than 0゚C.
Thawing of the seasonally frozen rockwall which underwent joint opening during the freezing phase can result in the release of rock debris falling onto snow-covered talus slopes. The number and sizes of the rockfall debris tended to increase with thaw penetration into the rockwalls. On average, the maximum rockfall activity was reached about 10 days behind the exposure of the rockwall from snow. The thermal conduction theory indicated that rockfall activity was maximized when the thawing front penetrated to 1-2 m depth of the rockwalls.

Report

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

    (15 results)

All Other

All Publications (15 results)

  • [Publications] Norikazu Matsuoka: "Diurnal freeze-thaw depth in rockwalls : field measurements and theoretical considerations" Earth Surface Processes and Land forms. 19. 423-435 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "A laboratory simulation on freezing expansion of a fractured rock" Annual Report, Institute of Geoscience, University of Tsukuba. 21. 5-8 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "Soil moisture variability in relation to diurnal frost heaving" Permafrost and Peinglacial Processes. 7(印刷中). (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 松岡憲和・酒井裕晃: "融雪期におけるカ-ル壁からの落石の発生過程" 地形. 17. 39-40 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 松岡憲和: "岩盤の凍結破壊に関する野外観測" 地形. 17. 40 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "Diurnal freeze-thaw depth in rockwalls : field measurements and theoretical considerations" Earth Surface Processes and Landforms. 19. 423-435 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "A laboratory simulation on freezing expansion of a fractured rock" Annual Report, Institute of Geoscience, University of Tsukuba. 21. 5-8 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "Soil moisture variability in relation to diurnal frost heaving" Permafrost and Periglacial Processes. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka and Hiroaki Sakai: "Rockfall activities from a cirque wall during snow-melting seasons" Transactions, Japanese Geomorphological Union. 17. 39-40 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "Field measurements on frost shattering of fractured rockwalls" Transactions, Japanese Geomorphological Union. 17. 39 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Norikazu Matsuoka: "A laboratory simulation on freezing expansion of a fractured rock" Annual Report,Institute of Geoscience,Unirersity of Tsukuba. 21. 5-8 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Norikazu Matsuoka: "Soil moisture variability in relation to diutnal frost heaving" Permafrost and Periglacial Processes. 7(印刷中). (1996)

    • Related Report
      1995 Annual Research Report
  • [Publications] 松岡憲知・酒井裕晃: "融雪期におけるカ-ル壁からの落石の発生過程" 地形. 17. 39-40 (199)

    • Related Report
      1995 Annual Research Report
  • [Publications] 松岡憲知: "岩盤の凍結破壊に関する野外観測" 地形. 17. 40 (199)

    • Related Report
      1995 Annual Research Report
  • [Publications] Norikazu Matsuoka: "Diurnal freeze-thaw depth in rockwalls: field measurements and theoretical consiclerations" Earth Surface Processes and Landforms. 19. 423-435 (1994)

    • Related Report
      1994 Annual Research Report

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

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