Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Evaluation of the Mechanical Characteristics of Frozen Sand, Considering Temperature and Confining Pressure Effects, in a Cryogenic Triaxial Compression Test

동결 삼축압축시험을 통한 동결 사질토의 온도 및 구속압력에 따른 역학적 특성 평가

  • Park, Sangyeong (Dept. of Civil, Environmental and Architectural Engrg., Korea Univ.) ;
  • Jung, Sanghoon (Plant Civil and Structural Team, Hyundai Engrg.) ;
  • Hwang, Chaemin (Dept. of Civil, Environmental and Architectural Engrg., Korea Univ.) ;
  • Choi, Hangseok (Dept. of Civil, Environmental and Architectural Engrg., Korea Univ.)
  • 박상영 (고려대학교 건축사회환경공학부) ;
  • 정상훈 (현대엔지니어링 플랜트토목설계팀) ;
  • 황채민 (고려대학교 건축사회환경공학부) ;
  • 최항석 (고려대학교 건축사회환경공학부)
  • Received : 2022.06.14
  • Accepted : 2022.07.18
  • Published : 2022.08.31
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Abstract

Most studies have conducted cryogenic triaxial compression tests with frozen specimens prepared in a separate mold by one-directional freezing. This method has the potential to generate residual stress in a frozen specimen and cannot be adopted to simulate the application of the artificial ground freezing method in the field. Therefore, in this study, novel equipment and procedure for the cryogenic triaxial compression test were proposed to overcome the limitations of existing test methods. Therefore, the mechanical characteristics of frozen sand, considering the effect of temperature and confining pressure, were evaluated. As the freezing temperature decreased, the brittleness of frozen sand increased, and the strength increased due to a decrease in the unfrozen water content and an increase in the ice strength. A higher confining pressure resulted in an increase in interparticle friction and the pressure melting phenomenon, which caused strength reduction. Thus, it was found that the mechanical behaviors of frozen sand were simultaneously affected by both temperature and confining pressure.

대부분의 선행연구는 동결 삼축압축시험 수행 시, 몰드를 사용하여 시료를 조성하고 단방향으로 동결을 진행하였다. 이는 동결된 시료에 잔류응력이 발생할 가능성이 있기 때문에 인공동결공법이 적용된 지반을 모사하는데 한계가 있다. 본 연구에서는 기존 시험방법의 한계를 보완할 수 있는 시험장비 및 시험방법을 제안하고, 제안된 방법으로 온도 및 구속압력에 따른 동결 사질토의 역학적 특성을 평가하였다. 동결온도가 낮아질수록 동결 사질토는 취성이 증가하였고, 부동수분의 감소 및 얼음자체의 강도 증가로 인하여 강도가 증가하였다. 구속압력의 증가는 강도저감 효과를 발생시키는 압력융해 현상과 강도증진 효과를 발생시키는 흙 입자의 마찰력 증가 모두를 야기하였다. 이처럼 동결 사질토의 역학적 거동은 구속압력과 동결온도의 복합적인 영향을 받는 것으로 나타났다.

Keywords

Acknowledgement

본 연구는 한국연구재단의 지원(NRF-2019R1A2C2086647)으로 수행되었으며, 이에 깊은 감사를 드립니다.

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