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모래 입자의 형상과 내부마찰각의 상관관계에 관한 연구

Shear Resistance of Sandy Soils Depending on Particle Shape

  • 서형석 (연세대학교 토목환경공학과) ;
  • 조유민 (연세대학교 토목환경공학과) ;
  • 윤태섭 (연세대학교 토목환경공학과) ;
  • 김광염 (한국건설기술연구원 Geo-인프라연구실)
  • Suh, Hyoung Suk (School of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Jo, Yumin (School of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Yun, Tae Sup (School of Civil and Environmental Engrg., Yonsei Univ.) ;
  • Kim, Kwang Yeom (Korea Institute of Civil Engineering and Building Technology)
  • 투고 : 2016.04.15
  • 심사 : 2016.05.25
  • 발행 : 2016.06.30

초록

본 연구에서는 영상처리 기법을 이용해 총 9개의 모래 시료의 형상을 정량화하여 전단강도와의 상관관계를 분석하였다. 분석 시료는 6개의 자연모래 시료와 3개의 부순모래 시료이며 이를 고해상도 3차원 X-ray CT 촬영하여 그로부터 개별 입자 영상을 분리하고 구형도(Sphericity) 및 이완도(Elongation)와 같은 형상 계수를 통해 모래 시편의 형상을 정량화 하였다. 또한 시료의 상대밀도를 다르게 조성하여 직접전단시험을 수행해 첨두내부마찰각(Peak friction angle)과 극한내부마찰각(Critical state friction angle)을 획득하였다. 시료의 구형도가 감소하고 이완도가 증가할수록, 첨두내부마찰각과 극한내부마찰각은 유사한 기울기를 보이며 증가함을 확인하였으며 두 내부마찰각 사이 절댓값 차이는 입자 형상보다는 상대밀도 차이로부터 기인함을 확인하였다.

This study presents the correlations between quantified particle shape parameters and internal friction angles for nine sand specimens including six natural sands and three crushed sands. Specimens are subjected to 3D X-ray computed tomographic imaging and their particles are segmented through the aid of image processing techniques. Shapes of segmented particles are then quantified through two shape parameters such as sphericity and elongation. The direct shear apparatus enables us to measure peak and critical state friction angles of sand specimens of distinct relative densities. The gathered data show that decreasing sphericity and increasing elongation cause increases in peak and critical state friction angle with similar gradients.

키워드

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