• Title/Summary/Keyword: Frost heaving susceptibility

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Effects of Freezing a Backfill Material under Undrained Condition on a Buried Pipe (포화 사질토 뒷채움재의 비배수 동결에 의한 매설 강관의 거동 - 실대형 모형실험 연구 -)

  • Kang, Jae-Mo;Lee, Jang-Guen;Kim, Hak-Seung;Lee, Sang-Yoon;Ryu, Byung-Hyun;Cho, Nam-Jun
    • Journal of the Korean Geotechnical Society
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    • v.30 no.8
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    • pp.39-47
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    • 2014
  • Frost heaving and thawing settlement cause unexpected stress around buried pipelines, which results in deformation and permanent demage. A large scale laboratory test has been performed to observe deformation, stress, and temperature of a buried pipe during atmospheric temperature changes. From the experimental results, the stress concentrated around the buried pipe is inevitable and deformation is caused by the frost heaving. Even though backfill materials are sandy soils which are normally assumed to be non frost susceptible, it is revealed that frost demage can happen due to drainage condition, the level of ground water table, and water content.

Assessment of the Correlation between Segregation Potential and Hydraulic Conductivity with Fines Fraction (세립분 함유량에 따른 동상민감성 지수와 수리전도도의 상관관계 평가)

  • Jin, Hyunwoo;Kim, Incheol;Eun, Jongwan;Ryu, Byung Hyun;Lee, Jangguen
    • Journal of the Korean Geotechnical Society
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    • v.37 no.12
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    • pp.47-56
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    • 2021
  • The cryosuction (negative pore pressure) in freezing soils causes groundwater migration from the frozen fringe to freezing front for ice lens formation. Frost heave and heaving pressure by ice lens cause damage to ground infrastructure. In order to prevent damage by the frost heave, various frost susceptibility criteria have been proposed. The SP (Segregation Potential) is the most widely used classification criterion for frost susceptibility in cold regions. The expansion of the ice lens by the migration of the groundwater is a key role in frost heave mechanism, and thus it is necessary to evaluate the hydraulic conductivity. In this paper, soil mixtures of coarse-fines (sand-silt) were prepared in various weight fractions and used for frost heave and column permeability test. For each case, the SP and the hydraulic conductivity were derived and correlations were analyzed. As a results, the transition threshold of the SP and the hydraulic conductivity were shown at 20% and 50% of the silt weight fraction, respectively. Although there are difference between these transition thresholds, these two coefficients show a specific correlation. In the future, additional study should be conducted for detailed analysis of the threshold transition values between SP and hydraulic conductivity.