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2014 Vol.30, Issue 9 Preview Page
Evaluation of Effect of Rock Joints on Seismic Response of Tunnels

터널의 지진응답에 대한 암반 절리의 영향 평가

Jin-Kwon Yoo1
,
Jaehoon Chang2
,
Du-Hee Park3*
,
Myung Sagong4
유 진권1
,
장 재훈2
,
박 두희3*
,
사공 명4
1Graduate Student, Dept. of Civil and Environmental Engrg., Hanyang Univ.
2Master, Dept. of Civil and Environmental Engrg., Hanyang Univ.
3Assistant Prof., Dept. of Civil and Environmental Engrg., Hanyang Univ.
4Senior Researcher, Korea Railway Research Institute
1한양대학교 건설환경공학과 박사과정
2한양대학교 건설환경공학과 석사
3한양대학교 건설환경공학과 부교수
4한국철도기술연구원 철도구조연구실 연구실장
*교신저자. *Corresponding Author. 
30 September 2014. pp. 41-55
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Abstract

In performing seismic analysis of tunnels, it is a common practice to ignore the rock joints and to assume that the rock mass surrounding the tunnel is continuous. The applicability of this assumption has not yet been validated in detail. This study performs a series of pseudo-static discrete element analyses to evaluate the effect of rock joint on the seismic response of tunnels. The parameters considered are joint intersection location, joint spacing, joint stiffness, joint dip, and interface stiffness. The results show that the joint stiffness has the most critical influence on the tunnel response. The tunnel response increases with the spacing, resulting in localized concentration of moment and shear stress. The response of the tunnel is the lowest for joints dipping at 45°. This is because large shear stresses result in rotation of the principal planes by 45°. In summary, the weathered and smooth, vertical or horizontal, and widely spaced joint set will significantly increase the tunnel response under seismic loading. The tunnel linings are shown to be most susceptible to damage due to induced shear stress, and therefore should be checked in the seismic design.

Keywords
Rock joint
Tunnel
Seismic response
Pseudo-static
Discrete element analysis

일반적으로 암반 터널 지진해석 시 절리의 영향을 무시하며 암반을 연속체라 가정한다. 하지만 이와 같은 가정의 적절성에 관해서는 연구된 바 없다. 본 연구에서는 응답변위법을 적용하여 지진동에 의하여 유발되는 암반 절리의 변위가 터널의 응답에 미치는 영향을 일련의 개별요소법을 이용하여 수치적으로 규명하였다. 해석에는 절리와 터널의 교차위치, 절리의 강성, 경사, 간격, 그리고 암반과 터널 사이의 인터페이스 강성이 고려되었다. 해석 결과, 절리의 강성이 터널에 가장 지배적인 영향을 미치는 것으로 나타났다. 절리의 간격은 클수록 변위가 국부적으로 집중되어 응답이 증가하는 것으로 나타났다. 절리의 경사는 정적인 경우와는 상반되게 45°에서 응답이 가장 작게 계산되었다. 이는 전단변형으로 인하여 수직면과 수평면에 큰 전단응력이 작용하여 주응력면이 45°로 회전하기 때문인 것으로 판단된다. 결과적으로 절리의 경사, 간격, 강성 모두 터널의 응답에 큰 영향을 미치며 특히 간격이 큰 미끈한 수직 또는 수평방향 절리가 터널을 통과하는 경우가 가장 위험한 것으로 나타났다. 또한 터널 라이닝에는 휨응력보다는 전단응력이 큰 폭으로 증가하므로 내진설계 시 이를 반드시 검토해야 할 것으로 판단된다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 30
  • No :9
  • Pages :41-55
  • Received Date : 2014-08-11
  • Revised Date : 2014-09-18
  • Accepted Date : 2014-09-19
  • DOI :https://doi.org/10.7843/kgs.2014.30.9.41
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