한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

한국지반공학회 (Korean Geotechnical Society)
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동적 원심모형실험을 이용한 등가전단보 토조의 성능 검증

Validation of Equivalent Shear Beam Container Using Dynamic Centrifuge Tests

  • 김윤아 (한국과학기술원 건설 및 환경공학과) ;
  • 이해인 (국방과학연구소) ;
  • 고길완 (한국과학기술원 건설 및 환경공학과) ;
  • 김동수 (한국과학기술원 건설 및 환경공학과)
  • Kim, Yoon-Ah (Dept. of Civil & Environmental Engrg., KAIST) ;
  • Lee, Hae-In (The 4th R&D Institute, Agency for Defense Development) ;
  • Ko, Kil-Wan (Dept. of Civil & Environmental Engrg., KAIST) ;
  • Kim, Dong-Soo (Dept. of Civil & Environmental Engrg., KAIST)
  • 투고 : 2020.09.14
  • 심사 : 2020.11.05
  • 발행 : 2020.11.30
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초록

동적 원심모형실험에서 사용되는 등가전단보(Equivalent Shear Beam, ESB) 토조는 모형지반과 토조 사이 발생할 수 있는 경계효과를 최소화함으로써 지진 시 실제 지반의 운동을 효과적으로 모사할 수 있다. KAIST에서 사용하는 등가전단보 토조는 성능이 검증된 바 있다(Lee 등, 2013). 그러나 토조의 노후화로 고유주기 및 동적 특성의 재검증이 필요하다. 따라서 본 연구에서는 동적 원심모형실험을 통해 등가전단보 토조의 동적 특성을 재평가하였다. 등가전단보 토조 자체의 고유주기를 산정하여 Lee 등(2013)의 결과와 비교 분석하였으며, 모래가 채워진 등가전단보 토조의 경계효과를 평가하였다. 실험 결과, 등가전단보 토조는 토조 자체의 강성 증가로 인해 토조 자체의 고유주기가 감소하였으나, 모래가 채워진 등가전단보 토조 벽체의 지진 시 시간 이력과 주파수 특성은 지반의 거동과 유사하였다. 또한, 등가전단보 토조에 조성한 모형지반과 수치해석을 통해 도출한 지반의 동적 응답도 유사하게 나타났다. 이를 통해 등가전단보 토조 자체의 고유주기 감소로 인한 지진 시 지반과 토조의 경계효과는 크지 않음을 알 수 있었다.

In dynamic centrifuge tests, equivalent shear beam (ESB) container minimizes the boundary effect between the soil model and the wall of the container so as to effectively simulate the boundary conditions of real field state. The ESB container at KAIST was evaluated to be performing properly by Lee et al. (2013). However, it is necessary to re-evaluate the performance of ESB container since the ESB container may have deteriorated over time. Thus, the performance of eight-year-old ESB container was re-evaluated through dynamic centrifuge tests. Firstly, the natural period of the empty ESB container was compared with the results of Lee et al. (2013). Then the boundary effect of sand-filled ESB container was evaluated. Results show that the dynamic behavior of the sand-filled ESB container was similar to that of the ground, despite a decrease in the natural period of the empty ESB container over time. In addition, the dynamic response of the ground built in the ESB container and the same ground simulated through numerical analysis with free-field boundary conditions were similar. Therefore, it was found that the boundary effect of the ESB container due to the decrease in the natural period was not significant.

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참고문헌

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