Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Verification of Numerical Analysis Technique of Dynamic Response of Seabed Induced by the Interaction between Seabed and Wave

파랑-지반 상호작용에 의한 해저지반의 동적응답 수치해석법 검증

  • Kang, Gi-Chun (Dam & Watershed Maintenance Dept., K-water) ;
  • Kim, Sung-Woung (Dept. of Civil and Environmental Engrg., Korea Maritime and Ocean Univ.) ;
  • Kim, Tae-Hyung (Dept. of Civil Engrg., Korea Maritime and Ocean Univ.) ;
  • Kim, Do-Sam (Dept. of Civil Engrg., Korea Maritime and Ocean Univ.) ;
  • Kim, Jae-Hong (Infrastructure Research Center KWIE, K-water)
  • 강기천 (한국수자원공사 댐.유역관리처) ;
  • 김성웅 (한국해양대학교 토목환경공학과) ;
  • 김태형 (한국해양대학교 건설공학과) ;
  • 김도삼 (한국해양대학교 건설공학과) ;
  • 김재홍 (한국수자원공사연구소)
  • Received : 2014.09.22
  • Accepted : 2015.01.08
  • Published : 2015.01.31
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Abstract

Seabed may undergo large excess pore water pressure in the case of long duration of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. Thus, it is necessary to develop a numerical technique which can precisely evaluate the dynamic response of seabed due to wave action. In this study, a new numerical technique named mixed model (2D NIT & FLIP models) was proposed. The dynamic wave pressure and water flow velocity acting on the boundary between seabed and the wave field was estimated using 2D-NIT model. This result was used as input data in FLIP program for investigation of dynamic response of seabed. To secure the reliability of the mixed model, the numerical analysis results of the mixed model were compared with Yamamoto's solution and Chang's experiment results. The comparison results indicated that there were some differences between them, but the general trend of the effective stress increment and the excess pore water pressure along the depth of seabed was similar to each other. Thus, this study clearly supports the plausibility of the numerical analysis of the mixed model.

해저지반에 고파랑이 장시간 지속적으로 작용하는 경우 과잉간극수압이 크게 발생할 수 있고, 이로 인한 유효응력의 감소로 최악의 경우는 액상화를 유발할 수 있다. 따라서, 파작용에 의한 발생되는 해저지반의 동적응답을 정확히 예측할 수 있는 수치해석방법이 필요하다. 본 연구에서는 복합모델(2D-NIT 모델 & FLIP 모델)을 사용한 새로운 수치 해석법을 제안하였다. 해저지반과 파동장이 접하는 경계면상에서 작용하는 파압과 유속을 2D-NIT모델로부터 산정하고, 이를 해저지반상의 외력으로 입력하여 FLIP으로부터 해저지반의 동적응답 거동을 조사하는 것이다. 복합모델의 신뢰성 확보를 위해 본 연구에서는 2D-NIT & FLIP 모델에 의한 수치해석결과를 기존의 Yamamoto 이론해 및 Chang 실험결과와 비교하였다. 그 결과 2D-NIT & FLIP 해석값과 차이는 있지만, 전체적으로 깊이에 따라 지반내의 유효응력 증분과 과잉간극수압증분의 변화양상이 상당히 잘 일치하고 있기 때문에 본 연구에서 제안된 2D-NIT & FLIP모델이 상당한 타당성을 가지고 있음을 확인 할 수 있었다.

Keywords

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