Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Changes of Undrained Shear Behavior of Sand due to Cementation

고결(Cementation)에 따른 모래의 비배수 전단거동 변화

  • Lee Woo-Jin (Dept. of Civil and Environmental Engrg., Korea Univ.) ;
  • Lee Moon-Joo (Dept. of Civil and Environmental Engrg., Korea Univ.) ;
  • Choi Sung-Kun (Dept. of Civil and Environmental Engrg., Korea Univ.) ;
  • Hong Sung-Jin (Dept. of Civil and Environmental Engrg., Korea Univ.)
  • 이우진 (고려대학교 사회환경시스템공학과) ;
  • 이문주 (고려대학교 사회환경시스템공학과) ;
  • 최성근 (고려대학교 사회환경시스템공학과) ;
  • 홍성진 (고려대학교 사회환경시스템공학과)
  • Published : 2006.04.01
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Abstract

Triaxial tests at isotropic confining pressure of 200 kPa were carried out to show the undrained shear behavior of artificially cemented sands, which were cemented by gypsum, and the influences of relative density and DOC (degree of cementation) were investigated from the results. The yield strength, the elastic secant modulus at yield point and the peak frictional angle of cemented sands increased abruptly compared to uncemented sands, and it was checked that cementation exerts more influence on the behavior of sand than the relative density. But after breakage of the cementation bonds, the relative density was more important factor on the behavior of sand than the cementation. Because the compressibility md the excess pore pressure of cemented sands were reduced due to the cementation bonds, the effective stress path of cemented sands was going toward to the total stress path of uncemented sands. The cementation of sand restricted the dialtion of sand at the pre-yield condition, but induced more dilation in the post-yield condition.

본 논문에서는 고결(Cementation)에 의한 모래의 비배수 거동변화를 파악하기 위하여 석고를 고결유발제로 사용한 시료를 조성한 후 등방삼축시험(CIU)을 실시하였으며, 상대밀도 및 고결정도에 따른 거동 양상을 분석하였다. 연구결과 모래의 고결은 항복강도$(q_y)$, 항복시 할선탄성계수$(E_y)$, 첨두마찰각$(\Phi_p)$의 상당한 증가를 유발시키고, 상대밀도보다 모래의 거동에 더 큰 영향을 끼치는 것으로 확인되었다. 그러나 고결결합이 파괴된 이후, 모래의 거동은 고결보다는 상대밀도의 영향을 더 크게 받는 것으로 나타났다. 또한 고결결합에 의한 압축성 감소는 간극수압 발생율을 감소시켜 고결모래의 유효응력 경로가 미고결 모래의 전응력 경로쪽으로 편향되어 발생하였다. 고결결합이 파괴되기 전에는 다일레이션 경향이 감소하지만, 결합이 파괴된 후에는 미고결 모래보다 더 큰 다일레이션 경향이 유발되었다.

Keywords

References

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