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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Experimental study on the tunnel behavior induced by the excavation and the structure construction above existing tunnel

기존터널 상부지반 굴착 후 구조물 설치에 따른 터널거동에 관한 실험적 연구

  • Cha, Seok-Kyu (Dept. of Civil System Engineering, Ajou University) ;
  • Lee, Sangduk (Dept. of Civil System Engineering, Ajou University)
  • 차석규 (아주대학교 대학원 건설시스템공학과) ;
  • 이상덕 (아주대학교 건설시스템공학과)
  • Received : 2018.03.20
  • Accepted : 2018.05.03
  • Published : 2018.05.31
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Abstract

Recently, the construction of the urban area has been rapidly increasing, and the excavation work of the ground has been frequently performed at the upper part of the existing underground structures. Especially, when the structure is constructed after the excavation of the ground, the loading and unloading process in the ground under the excavation basement can affect the existing underground structures. Therefore, in order to maintain the stability of the existing underground structure due to the excavation of the ground, it is necessary to accurately grasp the influence of the excavation and the structure load in the adjoining part. In this study, the effect of the excavation of the ground and the new structure load on the existing tunnel was experimentally implemented and the influence of the adjacent construction on the existing tunnel was investigated. For this purpose a large testing model with 1/5 scale of the actual size was manufactured. The influence of ground excavation, width of the load due to new structure, and distance between centers of tunnel and of excavation on the existing tunnel was investigated. In this study, it was confirmed that the influence on the existing tunnel gets larger, as the excavation depth get deeper. At the same distance, it was confirmed that the tunnel displacement increased up to three times according to the increase of the building load width. That is, the load width influences the existing tunnel larger than the excavation depth. As the impact of the distance between centers of tunnel and of excavation, it was confirmed that tunnel crown displacement decreased by 48%. The result showed that a tunnel is located in the range of 1D (D: tunnel diameter) from the center of excavation, the effect of excavation is the largest.

최근 도심지 공사가 급증하여 기존 지하구조물의 상부에서 지반굴착 공사가 빈번하게 이루어지고 있다. 특히 지반굴착 후 구조물이 시공되는 경우 굴착 저면 하부 지반 내에서 하중 제하, 재하 과정이 반복되므로 기존 지하구조물에 영향을 미칠 수 있다. 따라서 지반굴착으로 인한 기존 지하구조물의 안정을 유지하기 위해서는 인접부에서의 굴착 및 구조물 하중에 의한 영향을 정확히 파악해야 한다. 본 연구에서는 기존터널 상부에 지반 굴착 및 신규 구조물 하중이 가해지는 경우를 실험적으로 구현하여 인접시공이 기존 터널에 미치는 영향을 파악하였다. 이를 위해 실제 크기의 1/5로 축소한 대형모형시험기를 제작하여 굴착저면과 터널 천단 간의 거리를 일정하게 유지한 체 지반굴착, 구조물 하중의 폭, 기존 터널 중심과 지반 굴착 저면 중심과의 이격거리에 따른 영향을 파악하였다. 연구 결과, 동일 하중 크기에 대하여 굴착 깊이가 깊어질수록 기존 터널에 더 큰 영향을 작용하는 것을 확인하였다. 동일 이격거리에서 기존 터널에 영향은 건물하중 폭 증가에 따라 터널 내공변위가 최대 3배까지 증가하는 것을 확인하였다. 건물하중 폭의 영향이 굴착 깊이보다 더 크게 나타났다. 또한 수평으로 이격하는 경우는 터널 중심에서 1.0D 이격되면 터널 천단변위가 48% 감소하는 것을 확인할 수 있었으며, 이로부터 기존 터널 상부에 터파기 시공 위치에 따른 영향이 가장 크게 발생하는 위치는 1.0D (D: 터널직경)인 것으로 확인하였다.

Keywords

References

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