Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Dynamic Factor of Safety Calculation of Slope by Nonlinear Response History Analysis

비선형 응답이력해석을 통한 사면의 동적 안전계수 계산

  • Lee, Yonghee (Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.) ;
  • Kim, Hak-Sung (Central Research Institute, Korea Hydro & Nuclear Power Co., Ltd.) ;
  • Ju, Young-Tae (R&D Center, NEX Technology Co., Ltd.) ;
  • Kim, Daehyeon (Dept. of Civil Engrg., Chosun Univ.) ;
  • Park, Heon-Joon (Dept. of Civil Engrg., Seoul National Univ. of Sceince & Technology) ;
  • Park, Duhee (Dept. of Civil & Environmental Engrg., Hanyang Univ.)
  • 이용희 (한국수력원자력(주) 중앙연구원) ;
  • 김학성 (한국수력원자력(주) 중앙연구원) ;
  • 주영태 ((주)넥스기술) ;
  • 김대현 (조선대학교 토목공학과) ;
  • 박헌준 (서울과학기술대학교 건설시스템공학과) ;
  • 박두희 (한양대학교 건설환경공학과)
  • Received : 2021.03.16
  • Accepted : 2021.09.08
  • Published : 2021.09.30
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Abstract

Pseudo-static slope stability analysis method is widely used in engineering practice to calculate the seismic factor of safety of slope subjected to earthquake ground motions. Although the dynamic analysis method is well recognized to have the primary advantage of simulating the stress-strain response of soils, it is not often used in practice because of the difficult in estimating the factor of safety. In this study, a procedure which utilizes the dynamic analysis method to extract the transient dynamic factor of safety is devleoped. This method overcomes the major limitation of the pseudo-static method, which uses an empirically determined seismic coefficient to derive the factor of safety. The proposed method is applied to a slope model and the result is compared with that of the pseudo-static method. It is shown that minimum dynamic factor of safety calculated by the dynamic analysis is slightly larger than that determined from the pseudo-static method. It is also demonstrated that the dynamic factor of safety becomes minimum when the horizontal seismic coefficient and horizontal average acceleration are maximum.

유사정적해석법은 실무에서 지진 시 사면의 안전계수를 구하기 위하여 널리 사용되고 있다. 반면에 동적해석은 지진 시 지반의 응력-변형관계를 가장 잘 모사할 수 있다는 장점에도 불구하고 설계기준에서 요구되는 안전계수를 산정하기 어려워 실무적으로 그 활용이 많지 않았다. 본 연구에서는 비선형 응답이력해석으로 사면의 동적 안전계수를 산정하는 기법을 구축하였다. 이 방법은 최대가속도를 인위적으로 조절해서 지진계수를 산정하는 유사정적해석법의 문제점을 극복하며 사면 고유의 증폭 특성을 고려할 수 있다. 제안된 방법은 단일 사면에 대해서 적용하였으며 해석 결과를 유사정적해석법과 비교하였다. 본 연구에서 사용한 사면 사례에서는 동적해석결과로부터 계산된 사면의 최소 안전계수는 유사정적해석결과와 유사하게 평가되었으며, 수평방향 지진계수와 활동 토체의 평균 가속도가 최대가 되는 시점에서 동적 안전계수는 최소가 됨을 확인하였다.

Keywords

Acknowledgement

본 연구에 참여하셨으나 지금은 고인이 되신 KAIST 고(故) 김동수 교수님께 깊은 감사를 드립니다. 교수님께서는 탁월한 통찰력과 넉넉한 인품을 갖추신 국내 지진지반공학 분야의 개척자로서 앞으로도 지반분야 연구자들에게 귀감으로 남으실 것입니다. 교수님께서 편안히영면하시길 기원합니다.

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