Journal of the Korean Geotechnical Society (한국지반공학회논문집)

Korean Geotechnical Society (한국지반공학회)
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Determination of Coefficient of Variation of Shear Wave Velocity in Fill Dam for Reliability Based Analysis

신뢰성 기반 해석을 위한 국내 필댐 구성 재료의 전단파 속도 변동계수 결정

  • Received : 2020.03.17
  • Accepted : 2020.04.25
  • Published : 2020.04.30
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Abstract

Shear wave velocity (or shear modulus) is very important in the evaluation of seismic performance of a fill dam under an earthquake. A shear wave velocity profile can be determined by surface wave method such as HWAW and SASW methods but this profile has uncertainty caused by spatial variation of material property in a fill dam. This uncertainty in shear wave velocity profile could be considered using a coefficient of variation of material property in the reliability based analysis. In this paper, the possible 600 shear wave velocity profiles in the core and rockfill zone of fill dam were generated by the random shear wave velocity profile generation method, proposed by Hwang and Park, based on the field shear wave velocity profiles determined by the HWAW and SASW methods. And, through the statistical analysis of generated shear wave velocity profiles in the fill dam, the coefficient of variation (COV) of shear wave velocity with depth were evaluated for the core and rock filled zone of fill dam in Korea.

지진 하중 하에서 필댐의 거동은 필댐 구성 재료의 전단파 속도(또는 전단 탄성계수) 분포에 많은 영향을 받는다. 일반적으로 필댐의 전단파 속도 분포는 전단파 속도 주상도를 통해 나타낼 수 있다. 이때 댐 구성 재료의 전단파 속도는 일반적으로 필댐 내부에서 공간에 따른 변동성을 가지며, 댐에서 허용되는 한정된 수의 실험에서는 이러한 재료 물성치 공간 변동성을 결정론적으로 규명할 수 없다. 따라서 실험에서 얻어진 전단파 속도 주상도는 불확실성을 가지게 되며, 재료 물성치의 불확실성은 해석결과에 불확실성을 야기하게 된다. 신뢰성 기반 해석은 이러한 재료 물성치 불확실성에 의한 해석결과의 영향을 평가 할 수 있다. 신뢰성 기반 해석에서는 변동계수를 통해 재료 물성치의 불확실성을 평가하고, 이러한 불확실성에 의한 영향을 해석에 반영할 수 있다. 본 연구에서는 국내 필댐 심벽부와 사력부 구성 재료의 전단파 속도 변동계수(COV, Coefficient Of Variation)를 결정하였다. 이를 위해 국내 필댐 심벽부와 사력부에서 표면파 시험을 통해 결정된 전단파 속도 주상도들에 대해 Hwang and Park(2013)에 의해 개발된 랜덤 전단파 속도 주상도 생성 기법을 적용하여 국내 필댐 심벽부와 사력부에 존재 가능한 전단파 속도 주상도 600개를 생성하고 이에 대한 통계처리를 통하여 필댐 심벽부와 사력부의 깊이별 전단파 속도 변동계수를 결정하였다.

Keywords

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