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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Analysis of pillar stability according to reinforcement method for very near parallel tunnel

초근접 병렬터널 필라부 보강공법에 따른 안정성 분석

  • Jo, Young-Seok (Dept. of Civil and Environmental Engineering, Dongguk University) ;
  • Kim, Yun-Hee (Dept. of Civil and Environmental Engineering, Dongguk University) ;
  • Hong, Ji-Yeon (Dept. of Civil and Environmental Engineering, Dongguk University) ;
  • Kim, Dong-Gyou (Korea Institute of Civil Engineering and Building Technology) ;
  • Kim, Bumjoo (Dept. of Civil and Environmental Engineering, Dongguk University)
  • 조영석 (동국대학교 건설환경공학과) ;
  • 김윤희 (동국대학교 건설환경공학과) ;
  • 홍지연 (동국대학교 건설환경공학과) ;
  • 김동규 (한국건설기술연구원) ;
  • 김범주 (동국대학교 건설환경공학과)
  • Received : 2021.02.25
  • Accepted : 2021.03.12
  • Published : 2021.03.31
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Abstract

In general, the stress is concentrated on the pillar of very near parallel tunnel (VNPT), and the pillar has been reinforced by using steel-wires to maintain the stability of the tunnel. However, since the strength of the pillar decreases in the soil layer, the reinforcing pillar with the steel-wires is insufficient for tunnel stability. In this study, the laboratory tunnel experiment was conducted to examine the reinforcement effect for a new method, of which the pillar of VNPT is strengthened by using steel-pipes. As a result, against overburden stress, the bearing capacity of the steel-pipe reinforcement was 22% greater than that of the steel-wire reinforcement. In using the Particle Image Velocimetry method, the analysis shows that the steel-pipe reinforcement forms a more favorable condition of which uniformly the overburden load acts on the VNPT and the pillar than the steel-wire reinforcement. Based on the results, the steel-pipe reinforcement is expected to bring a more positive effect on tunnel stability than the steel-wire reinforcement.

초근접 병렬터널의 필라부에는 응력이 집중되고, 기존에는 터널의 안정성을 확보하기 위하여 강연선을 이용하여 필라부를 보강한다. 하지만 토사 지반에서는 필라부의 강도가 감소하기 때문에 필라부를 강연선으로 보강하는 것으로는 터널 안전성을 충분히 확보하지 못한다. 본 연구에서는 초근접 병렬터널의 필라부를 강관으로 보강하는 새로운 공법의 보강효과를 검토하기 위하여 실내터널모형실험을 수행하였다. 그 결과 상부응력에 대한 필라부의 지지능력은 강관 보강하는 경우가 강연선 보강하는 경우보다 22% 큰 것으로 나타났다. Particle Image Velocimetry 기법을 이용한 분석결과 필라부 강관 보강은 강연선 보강보다 병렬터널과 필라부에 상재하중이 균일하게 작용할 수 있는 더 유리한 조건을 형성하였다. 실험결과에 기반하여 필라부 강관보강공법은 강연선 보강공법보다 터널 안정성에 긍정적인 효과를 가져올 것으로 기대된다.

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References

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