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2023 Vol.33, Issue 4 Preview Page

Technical Note

Roughness Effect on the Residual Shear Characteristics of Jumunjin Sands

거칠기 효과를 고려한 주문진 표준사의 잔류전단강도 특성 분석

Sueng-Won Jeong1*
정 승원1*
1Principal Researcher, Geologic Hazards Division, Korea Institute of Geoscience and Mineral Resources
1한국지질자원연구원 지질재해연구본부 책임연구원
*Corresponding Author
31 December 2023. pp. 717-724
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Abstract

Residual shear strength is an important parameter in landslide dynamics and may be considered the critical factor in landslide triggering. Tests were undertaken using Jumunjin sands to examine the effects of smooth and rough surfaces on ring-shear characteristics. Under dense and drained conditions, shear velocities were recorded as 0.01, 0.1, 1, 10, 50, 100 mm s-1, with shear strength increasing with velocity and producing increasingly fine content. Particle fragmentation may thus increase landslide mobilization when the landslide body is mixed with ambient water in channelized flows.

Keywords
residual shear strength
ring shear test
roughness effect
Jumunjin sand
particle fragmentation

잔류전단강도(residual shear strength)는 산사태와 토석류 해석시 사용되는 중요한 인자이다. 잔류전단강도는 흙이 전단될 때 발현되는 최소 전단응력으로 산사태 발생시점에서의 전단강도이다. 본 연구는 링전단시험장치를 사용하여 주문진 모래에 대한 잔류전단강도를 측정하였다. 거칠기 효과를 검증하기 위하여 링전단상자를 거친면(rough surface)과 매끈면(smooth surface)으로 달리 제작하여 흙 시료가 전단될 때 거칠기(roughness)에 따른 전단특성을 조사하고자 하였다. 시험은 조립상태, 배수조건에서 전단속도를 0.01, 0.1, 1, 10, 50, 100 mm/s로 달리 적용하여 각 전단속도에 따른 전단응력을 측정하고, 각 시험단계별 잔류전단강도를 측정하였다. 실험결과에 따르면, 일반적으로 전단강도는 전단속도가 증가하면 증가한다. 또한 전단시간이 길어질수록, 전단속도가 증가할수록, 링전단상자 하부링에서 더 많은 미립분이 쌓인다는 것을 확인하였다. 이러한 결과로 입자 파쇄량이 증가할수록 산사태 발생이후 토석류 확산시에 유동성을 증가시키는 원인으로 판단할 수 있다.

키워드
잔류전단강도
링전단시험
거칠기 효과
주문진 표준사
입자 파쇄
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Information
  • Publisher :Korean Society of Engineering Geology
  • Publisher(Ko) :대한지질공학회
  • Journal Title :The Journal of Engineering Geology
  • Journal Title(Ko) :지질공학
  • Volume : 33
  • No :4
  • Pages :717-724
  • Received Date : 2023-10-20
  • Accepted Date : 2023-11-06
  • DOI :https://doi.org/10.9720/kseg.2023.4.717
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