Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Post-Liquefaction Induced Ground Settlement by Dissipation of Porewater Pressure under Drained Condition

지반 배수조건을 고려한 액상화 이후 과잉간극수압 소산에 따른 지반의 침하

  • Yun, Seong-Kyu (Engrg. Research Institute, Gyeongsang National Univ.) ;
  • Kim, Donghwan (Dept. of Civil Engrg., College of Engrg., Gyeongsang National Univ.) ;
  • Yang, Yeongchan (Dept. of Civil Engrg., College of Engrg., Gyeongsang National Univ.) ;
  • Kang, Gichun (Dept. of Civil Engrg., College of Engrg., Gyeongsang National Univ.)
  • 윤성규 (경상국립대학교 공학연구원) ;
  • 김동환 (경상국립대학교 공과대학 토목공학과) ;
  • 양영찬 (경상국립대학교 공과대학 토목공학과) ;
  • 강기천 (경상국립대학교 공과대학 토목공학과)
  • Received : 2022.01.04
  • Accepted : 2022.04.12
  • Published : 2022.06.30
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Abstract

In the case of domestic seismic design, deformation of structures and ground is reviewed through undrained condition analysis and applied to design and maintenance. However, when the ground undergoes dissipation after liquefaction due to a dynamic load such as an earthquake, additional displacement occurs and greater damage occurs. Therefore, it is necessary to additionally analyze the drained conditions, It is necessary to grasp the exact ground behavior such as calculating and reviewing the amount of subsidence of the ground that has undergone the loss process after an earthquake and apply it to design and maintenance together. Therefore, in this study, numerical analysis was performed assuming undrained and drained conditions by dividing pure sandy soil into loose soil with Dr=30% and high-density soil with Dr=70%. In particular, when a dynamic load such as an earthquake is applied, considering the drained conditions of the ground, the settlement amount and the pore water pressure ratio of loose and dense ground are compared, This study focused on comparative analysis of settlement amount and pore water pressure ratio in the process of ground loss after an earthquake. As a result, the amount of subsidence during the dissipation process was 30 to 60 times greater than that of the earthquake.

국내 내진설계의 경우, 일반적으로 비배수 조건 해석을 통해 구조물과 지반의 변형을 검토하여 이를 설계 및 유지보수에 적용한다. 하지만 지진과 같은 동적하중에 의해 발생한 액상화 현상 이후 과잉간극수압의 소산과정을 거치게 되면 추가적인 지반의 침하가 발생하고 그에 따른 더 큰 피해가 발생한다. 그러므로 배수조건의 해석이 추가적으로 요구되는 실정이며, 지진이 끝난 후 소산과정을 거친 지반의 침하량을 산정하고 검토하는 등의 정확한 지반의 거동을 파악해 이를 설계 및 유지보수에 함께 적용해야 한다. 따라서 본 연구는 순수 사질토 지반을 Dr=30%의 느슨한 지반과 Dr=70%의 조밀한 지반으로 구분하여 비배수조건과 배수조건을 가정해 수치해석을 실시하였다. 특히, 지진과 같은 동적하중이 작용할 때, 지반의 배수조건을 고려하여 느슨한 지반과 조밀한 지반의 침하량 및 과잉간극수압비를 비교하고, 지진이 끝난 후 지반의 소산과정에서 나타나는 침하량 및 과잉간극수압비를 비교, 분석하는 부분에 초점을 맞췄다. 그 결과 지진 시 발생한 지반의 침하량 보다 소산과정을 거친 지반의 침하량이 약 30~60배 큰 결과를 얻었다.

Keywords

Acknowledgement

이 논문은 2020년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임(No.NRF-2020R1I1A3067248).

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