KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Reliability Assessment of Ambient Noise HVSR per Observation Condition

관측 환경에 따른 상시미동의 HVSR 결과 신뢰도 평가

  • 유병호 (한양대학교 ERICA 건설환경공학과) ;
  • 최우정 (한양대학교 ERICA 건설환경공학과) ;
  • 최인혁 (한양대학교 건설환경시스템공학과) ;
  • 곽동엽 (한양대학교 ERICA 건설환경공학과)
  • Received : 2020.12.04
  • Accepted : 2021.06.21
  • Published : 2022.02.01
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Abstract

The horizontal-to-vertical spectral ratio (HVSR) of ambient noise is widely used to identify the resonant frequency of a site. The frequency at the largest HVSR is regarded as the resonant frequency. The source of ambient noise is impossible to identify and control. Therefore, obtaining reliable HVSR of ambient noise requires sufficient measurement time and absence of near-field vibration. In this study, we investigated the minimum stabilization time required for a portable seismometer and the effect of the distance between the seismometer and artificial vibration on HVSR estimation. In the case of a soil site, the HVSR was stabilized after 5 minutes after sensor installation. In the case of a rock site, stabilization required more than an hour. Human-footsteps within 10 m of the seismometer strongly influenced the HVSR for the soil site. These results provide a field guideline when measuring ambient noise for HVSR.

상시미동의 수직성분에 대한 수평성분 스펙트럼비(HVSR)는 부지 공명주파수를 파악하는데 활발히 사용되고 있다. HVSR의 가장 큰 비율을 가지는 주파수는 부지 공명주파수와 일치한다. 상시미동은 부지 주변에 존재하는 미세진동을 의미하기 때문에 직접적인 진동원을 파악할 수 없으며, 또한 조절할 수 없다. 따라서 신뢰적인 상시미동 HVSR을 구하기 위해서는 상시미동 측정에 충분한 시간적 여유와 주변 환경의 파악 또한 필요하다. 본 연구에서는 신뢰적인 HVSR 분석에 필요한 상시미동 측정 최소시간과 지진계와 인위적인 진동 사이의 이격거리의 영향을 알아보았다. 토사 부지의 경우 센서 설치 후 5분 이내에 안정화가 되었으나, 암반 부지의 경우 안정화까지 1시간 이상이 소요되었다. 또한 상시미동 관측 시 발걸음 진동이 지진계 10 m 이내에 존재할 경우 HVSR결과에 큰 영향을 미치는 것을 확인하였다. 이러한 결과는 현장에서 상시미동의 HVSR측정에 필요한 가이드라인을 제공할 것으로 기대된다.

Keywords

Acknowledgement

이 논문은 2020 CONVENTION 논문을 수정·보완하여 작성되었습니다. 또한 본 연구는 국토교통부 국토교통기술촉진연구사업의 연구비지원(과제번호 21CTAP-C152247-03)에 의해 수행되었습니다. 이에 깊은 감사를 드립니다. 본 논문은 2020 CONVENTION 논문을 수정·보완하여 작성되었습니다.

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