Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Acceleration Variation of Surrounding Ground according to distance from Strip-Type Crushed Stone Foundation

쇄석 띠기초와의 거리에 따른 주변지반의 가속도 변화

  • Son, Su-Won (Department of Civil and Environmental Engineering, Pusan National University) ;
  • Son, Tae-Ik (Department of Civil and Environmental Engineering, Pusan National University) ;
  • Kim, Soo-Bong (Department of Civil and Environmental Engineering, Pusan National University) ;
  • Kim, Jin-Man (Department of Civil and Environmental Engineering, Pusan National University)
  • 손수원 (부산대학교 사회환경시스템공학과) ;
  • 손태익 (부산대학교 사회환경시스템공학과) ;
  • 김수봉 (부산대학교 사회환경시스템공학과) ;
  • 김진만 (부산대학교 사회환경시스템공학과)
  • Received : 2018.10.01
  • Accepted : 2019.01.04
  • Published : 2019.01.31
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Abstract

In this study, the acceleration changes of the surrounding ground when crushed stones were installed in a strip-type were analyzed using the 1-G shaking table test. The ground was constructed from clay, and the foundation was installed using crushed stone of strip-type form. The response acceleration and response spectrum for various input seismic motions were analyzed. The change in acceleration was examined according to the adjacent distance to the strip-type crushed stone foundation. In the Hachinohe seismic motion results, there was no significant decrease in acceleration, but the maximum response acceleration for the two seismic motions was inversely proportional to the distance from the crushed stone foundation. As a result of the response spectrum analysis, the attenuation period in the long period and the short period input wave were different from each other, and the change in response spectrum affected the maximum acceleration value. As the distance from the crushed stone foundation was increased, the attenuation was larger in the period between 0.08 and 0.5 sec in the Hachinohe seismic motion, the attenuation was larger in the period of less than 0.2 seconds in the Northridge seismic motion.

국내외에서 점토층이나 준설토 등이 있는 연약지반을 개량하고, 그 지반위에 구조물을 건설하는 수요는 점차적으로 늘어나고 있다. 그리고 이러한 개발과 더불어 태풍, 산사태, 지진 등과 같은 자연재해의 빈도와 규모도 증가하고 있다. 이러한 자연재해로 인한 피해를 예방하기 위한 방법 중 하나가 지반개량공법이다. 본 연구에서는 쇄석을 띠기초 형식으로 설치하였을 때의 주변지반의 가속도 변화를 1-G 진동대 실험을 이용하여 분석하였다. 점토를 이용하여 지반을 조성하고 기초는 쇄석을 띠형식으로 설치하였다. 주기가 다른 입력지진파에 대해 응답가속도와 응답스펙트럼을 분석하였다. 쇄석 띠기초와의 인접거리에 따른 가속도 변화를 분석하여 지진시 쇄석 띠기초가 주변지반의 가속도 변화에 미치는 영향을 평가하였다. Hachinohe 지진파 결과에서는 쇄석띠기초와의 거리에 비해 가속도가 큰 감소는 없지만, 두가지 지진파에 대한 최대응답가속도가 쇄석띠기초와의 거리에 반비례하였다. 응답스펙트럼 분석결과, 장주기와 단주기 입력파에서의 감쇠되는 주기가 달랐으며, 이와 같은 응답스펙트럼 변화가 가속도의 최대가속도값에 영향을 준 것으로 판단된다. Hachinohe 지진파에서는 쇄석띠기초와 멀어질수록 0.08~0.5초 사이의 주기에서 감쇠가 컸으며, Northridge 입력파에서는 쇄석띠기초와 멀어질수록 0.2초 이내의 주기에서 감쇠가 컸다.

Keywords

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Fig. 1. Ground and Foundation Installation Step

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Fig. 2. Experiment setup

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Fig. 3. Input motion

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Fig. 4. Response acceleration at each location (Hachinohe)

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Fig. 5. Response acceleration at each location (Northridge)

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Fig. 6. Response acceleration according to distance from strip foundation

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Fig. 7. Response spectrum at each location

Table 1. Material properties of the model ground

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