Journal of Korean Tunnelling and Underground Space Association (한국터널지하공간학회 논문집)

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Application of non-destructive method for evaluation of soil nail length

쏘일네일의 길이평가를 위한 비파괴 기법의 적용

  • Kim, Ki-Hong (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Kim, Nag-Young (Korea Expressway Corporation) ;
  • Lee, Jong-Sub (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Yu, Jung-Doung (School of Civil, Environmental and Architectural Engineering, Korea University)
  • 김기홍 (고려대학교 공과대학 건축사회환경공학부) ;
  • 김낙영 (한국도로공사 도로교통연구원 환경연구실) ;
  • 이종섭 (고려대학교 공과대학 건축사회환경공학부) ;
  • 유정동 (고려대학교 공과대학 건축사회환경공학부)
  • Received : 2014.12.31
  • Accepted : 2015.03.23
  • Published : 2015.03.31
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Abstract

As soil nails support a ground by the friction between nails and soils being reinforced, the length of soil nails is important factor for a ground stability. Thus, the soil nail length has to be accurately evaluated in order to secure a ground stability. The goal of this study is to suggest the applicability of the non-destructive method as the basic research for the evaluation of the soil nail length. First, the elastic and electromagnetic waves are adopted to select an applicable method for the soil nails connected by the coupler. Test results show that while the ultrasonic waves are not detected due to the coupler, the electromagnetic waves are free for the influence of the coupler. Second, electromagnetic waves are measured for combined soil nails with the length of 1 m~15 m for the investigation of the characteristics of electromagnetic waves. The travel time of the electromagnetic wave increases with an increase in the soil nail length. In addition, the ground cable is used to apply the electromagnetic waves to pre-installed soil nails. Test results show that the travel time of the electromagnetic wave by using the ground cable increases with an increase in soil nail length. This study demonstrates that the electromagnetic wave may be a promising method for the evaluation of the soil nail length.

쏘일네일은 지반과 네일간에 발생하는 마찰특성을 이용하여 지반을 보강하기 때문에 쏘일네일의 길이는 지반의 안정성에 매우 중요한 요소이다. 이와 같은 이유로 쏘일네일의 길이를 정확히 평가하여 지반의 안정성을 확보해야 한다. 본 연구는 쏘일네일의 길이를 평가하는 기법을 개발하기 위한 기초 연구로써 비파괴기법의 적용성을 제시하고자 한다. 첫째, 커플러로 연결된 철근에도 적용 가능한 기법을 개발하기 위해 초음파와 전자기파를 적용한 실험을 수행하였다. 실험 결과, 초음파는 커플러의 영향으로 신호를 측정할 수 없는 반면, 전자기파의 경우 커플러의 영향 없이 신호를 측정할 수 있었다. 둘째, 쏘일네일의 길이에 따른 전자기파 신호양상을 파악하기 위해 1 m~15 m의 길이가 되도록 철근을 조합한 후, 전자기파를 측정하였다. 그 결과, 철근의 길이가 증가할수록 전자기파의 도달시간이 증가하는 것으로 나타났다. 또한, 기 설치된 쏘일네일에도 적용할 수 있도록 접지선을 이용한 실험도 수행하였다. 실험결과, 접지선을 이용한 경우에도 철근의 길이가 증가할수록 전자기파의 도달시간도 증가하는 것으로 나타났다. 본 연구의 결과는 전자기파가 쏘일네일의 길이를 평가하기에 유용한 기법임을 보여준다.

Keywords

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Cited by

  1. Non-destructive Health Monitoring of Soil Nails Using Electromagnetic Waves 2018, https://doi.org/10.1139/cgj-2017-0043
  2. Nondestructive Integrity Evaluation of Soil Nails Using Longitudinal Waves vol.144, pp.11, 2018, https://doi.org/10.1061/(ASCE)GT.1943-5606.0001976