한국지반공학회논문집 (Journal of the Korean Geotechnical Society)

한국지반공학회 (Korean Geotechnical Society)
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입자-유체 상호거동을 고려한 지진시 포화 모래지반의 밀도 결정

Determination of Density of Saturated Sand Considering Particle-fluid Interaction During Earthquake

  • 김현욱 (한국수력원자력 중앙연구원) ;
  • 이세현 (한국원자력안전기술원 원자력검사단 한울규제실) ;
  • 윤준웅 (국토안전관리원 기업성장응답센터)
  • 투고 : 2022.08.23
  • 심사 : 2022.09.13
  • 발행 : 2022.10.31
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초록

전단파 속도를 기반으로 포화 지반의 최대 전단탄성계수를 산정하는데 이용되는 매질의 밀도가 명확하지 않아 이를 결정하고자 검증식을 구성하고, 시나리오를 수립하여 실내 실험결과와 비교하였다. 매질의 밀도는 포화, 습윤, 건조, 수중 밀도 조건으로 가정하였고, 각 경우별 건조지반 전단파속도 대비 포화지반 전단파속도의 비를 산정하였다. 포화 밀도 가정시 전단파속도 비는 공진주 실험 결과에 의한 전단파속도 비와 일치하였고, 습윤 밀도 가정시에는 벤더엘리먼트 실험 결과에 의한 값과 일치하였다. 이는 특성 주파수를 경계로 흙입자와 유체의 거동을 정의하는 Biot(1956)의 이론과 일치하는 결과이며, 일반적으로 고려되는 지진의 주파수 범위를 고려한다면 포화 지반에서는 포화 밀도를 적용하는 것이 타당할 것으로 사료된다.

The mass density of the medium (ρ) used to calculate the maximum shear modulus (Gmax) of the saturated ground based on the shear wave velocity is unclear. Therefore, to determine the mass density, a verification formula and five scenarios were established. Laboratory tests were conducted, and the obtained results were compared. The mass density of the medium was assumed to be saturated (ρsat), wet (ρt), dry (ρdry), and submerged conditions (ρsub), and the Vs ratios of saturated to dry condition were obtained from each case. Assuming the saturated density (ρsat), the Vs ratio was consistent with the value from the resonant column test (RCT) results, and the value from the bender element test results was consistent with the wet density assumption (ρt). Considering the frequency range of earthquakes, it is concluded that applying the saturated density (ρsat) is reasonable as in the RCT results.

키워드

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