A study on the optimum range of reinforcement in tunneling adjacent to structures

구조물 근접 터널시공시 최적의 보강범위에 관한 연구

  • 이홍성 (현대건설(주) 기술/품질 개발원) ;
  • 김대영 (현대건설(주) 기술/품질 개발원) ;
  • 천병식 (한양대학교 공과대학 토목공학과) ;
  • 정혁상 (한양대학교 공과대학 토목공학과)
  • Published : 2009.06.30

Abstract

Development of underground space is actively performed globally for better life in the surface, and the scale of the space is increasing. Extreme care should be taken in the construction of the underground space in urban areas in order to avoid damage of adjacent structures and interference with existing underground space. In case of shallow tunnels, reinforcement of ground and structures is necessary to minimize the damage to structures due to excavation but any standard for optimum range of the reinforcement has not been established yet. In this paper, a series of numerical analyses have been performed for a 20 m diameter tunnel excavated underneath a structure to investigate the degree of damage of the structure according to vertical and horizontal spacing between the tunnel and structure. In addition to that, optimum range of reinforcement is presented for each case where reinforcement is required. It has been observed that the reinforcement is necessary for the ground condition adapted in the analyses as follows: (1) if horizontal spacing ($S_{H}$) approaches to 0D (D: equivalent diameter of tunnel) for vertical spacing (Sv) of 0.5D, and (2) if tunnel exists underneath the structure for vertical spacing (Sv) of 0.75D. The reinforcement is not necessary for Sv of 10 regardless of $S_{H}$. It also has been obtained that the optimum ranges of the reinforcement around structure foundation are 7 m in depth and whole width of the structure and 5 m beyond tunnel sidewall. These reinforcememt ranges have been confirmed to be enough for stability of the structure if types of reinforcement method is appropriately selected.

References

  1. 배규진 등 (1998), “Neural Network을 이용한 터널 설계 적정성 평가용 Expert System 개발”, 건설기술연구원
  2. 이홍성 (2004), “미고결 암반층에서의 붕괴터널 대책사례", 현대건설 2004 기술세미나 논문집.
  3. 임해식, 김경민 (2002), “한국산 고화재에 의한 연약지반의 개량효과-용도별 고화재에 따른 개량지반의 설계 정수를 중심으로-", 한국지반환경공학회, 지반환경 제 3권 제 2호, pp. 11-19.
  4. (사)한국터널공학회 (2002), 터널의 이론과 실무.
  5. 천병식 등 (2001), “그라우트재의 호모겔과 샌드겔의 강도증진 성상에 관한 연구”, 한국지반환경공학회 학술발표회 논문집.
  6. 首都高速道路公團 保全施設部(1982), “首都高速道路に近接する構造物の施工指導要領事(案)".
  7. (社)日本藥液注入協會(1988), “藥液注入工法 設計.施工指針).
  8. 土木硏究所 基礎硏究室 (1983), “近接基礎設計施工要領(案)", 土木硏究所資料第 2009号
  9. Attewell, P. B. (1977), “ Ground movements caused by tunelling in soil", Proc. of International Conference on Large Movements and Structures, London, pp. 812-948.
  10. Attewell, P. B. et al. (1986), “ Soil movements induced by tunnelling and their effects on pipelines and structures", Blackie, Glasgow.
  11. Baumann, V. (1984), “Das soilcrete-verfahren in der baupraxis", Vortrage der Baugrundtagung, Dusseldorf.
  12. Burland, J. B. (1995), “ Assessment of risk of damage to buildings duε to tunnelling and excavation", 1st Conference on Earthquake Geotech. Engineering.
  13. Boscardin, M. D. and Coridng, E. J. (1989), “ Building response to excavation-induced settlement", Journal of Geotechnical Engineering, Vol. 115, No. 1, pp. 1-21. https://doi.org/10.1061/(ASCE)0733-9410(1989)115:1(1)
  14. Bjerrum, L. (1963), “ Discussion to european conference on soil mechanics and foundation engineering", Wiesbaden, Vol. III, pp. 135.
  15. Cording, E. J. (1984), “ Use of empirical data for braced excavations and tunnels in soil", Lecture Series, Chicago ASCE, Chicago, IL.
  16. Cording, E. J. and Hansmire, W. H. (1975), “Displacements around soft ground tunnels", General Report, Session IV, Tunnels in Soil 5th Pan American Congress on Soil Mechanics and Foundation Engineering, Buenos Aires
  17. Hergarden, H. J. A. M., Van der Poel, J. T. and Van der Schrier, J. S. (1996), “Ground movements due to tunnelling influence on pile foundation", Geotechnical Aspects of Underground Construction in Soft Ground, Rotterdam, Balkema, pp. 519-524
  18. Jacobsz, S. W., Standing, J. R., Mair, R. K., Soga, K., Hagiwara, T. and Sugiyama, T. (2001), "Tunnelling effect on driven Piles", Proc. of International Conference on Response of Buildings to Excavation-Induced Ground Movements, Imperial College, London, CIRIA, pp. 1-15.
  19. Lee, H. S., Jue, K. S., Kim, D. Y., Jung, W. H. and Lee, Y. N. (2007), “Urban tunneling under existing structure", Proceedings of ITA 2007.
  20. Morton, J. D. and King, K. H. (1979), “Effects of tunnelling on the bearing capacity and settlements of piled foundations", Proc. Tunnelling ’79, IMM, pp. 57-68
  21. Lee, Y. J. (2004), “Tunnelling adjacent to a row of loaded piles", Ph. D Thesis, University College London.
  22. Peck, R. (1969), “Deep excavations and tunneling in soft ground", Proc., 7th Int'l Conf. on Soil Mech. and Foun. Engr., Mexico City, State-of-the-Art, pp. 225-290
  23. Son, M. R. and Cording, E. J. (2005), "Estimation of building damage due to excavation-induced ground movements", Joumal of Geotechnical and Geoenvironmental Engineering, Vol. 131 , No. 2, ASCE, pp. 162-177. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:2(162)
  24. Sowers, G. F. (1962), “ Shallow foundation", Foundation Engineering, G. A. Leonards, Ed., McGraw-Hill, New York, pp. 525