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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Analysis for Dynamic Behavioral Characteristics of Submerged Floating Tunnel according to Shore Connection Designs

지반 접속부 설계에 따른 수중터널의 동적 거동 특성에 대한 수치해석적 연구

  • Seok-Jun, Kang (Dept. of Civil and Environmental Engineering, KAIST) ;
  • Joohyun, Park (Dept. of Civil and Environmental Engineering, KAIST) ;
  • Gye-Chun, Cho (Dept. of Civil and Environmental Engineering, KAIST)
  • 강석준 (한국과학기술원 건설및환경공학과) ;
  • 박주현 (한국과학기술원 건설및환경공학과) ;
  • 조계춘 (한국과학기술원 건설및환경공학과)
  • Received : 2023.01.05
  • Accepted : 2023.01.27
  • Published : 2023.01.31
Download PDF
⟨ Previous Next ⟩

Abstract

Submerged floating tunnels must be connected to the ground to connect continents. The displacement imbalance at the shore connection between the underground bored tunnel and submerged floating tunnel can cause stress concentration, accompanying a fracture at the shore connection. The elastic joint has been proposed as a method to relive the stress concentration, however, the effect of the elastic joints on the dynamic behavior should be evaluated. In this study, the submerged floating tunnel and shore connection under dynamic load conditions were simulated through numerical analysis using a numerical model verified through a small-scaled physical model test. The resonant frequency was considered as a dynamic behavioral characteristic of the tunnel under the impact load, and it was confirmed that the stiffness of the elastic joint and the resonant frequency exhibit a power function relationship. When the shore connection is designed with a soft joint, the resonant frequency of the tunnel is reduced, which not only increases the risk of resonance in the marine environment where a dynamic load of low frequency is applied, but also greatly increases the maximum velocity of tunnel when resonance occurs.

수중터널은 내륙 간 연결을 위해 지반에 접속되어야 한다. 지반 접속부에 연결된 지중터널과 수중터널이 보이는 변위 불균형은 응력 집중을 야기할 수 있으며, 이를 해결하기 위한 방법으로 탄성 조인트를 활용할 경우에는 정적 하중 조건에서 지반 접속부의 응력 집중은 해소시킬 수 있음이 선행 연구에서 확인되었다. 그러나, 지속적으로 거동하는 수중터널의 구속조건을 고려했을 때 지반 접속부의 동적 거동과 안정성에 탄성 조인트의 활용이 미치는 영향이 검토되어야 한다. 본 연구에서는 동적 하중 조건의 수중터널 및 지반 접속부를 수치해석적 방법을 통해 모사하였으며, 동일 상황을 모사한 축소 모형시험을 통해 수치해석 모델을 검증하였다. 다양한 물성의 탄성 조인트가 설치될 경우에 대한 수치해석적 모사를 통해 탄성 조인트 강성에 따른 수중터널의 고유진동수 변화와 공진 거동을 분석하였다. 그 결과, 조인트의 강성과 고유진동수가 멱함수 관계를 가짐이 확인되었다. 낮은 강성의 조인트로 지반 접속부가 설계될 경우, 수중터널의 고유진동수는 감소하여 낮은 진동수의 동하중이 가해지는 해양 환경에서 공진의 위험이 증가할 뿐만 아니라 공진 발생 시 최대 속도가 크게 증가하였다. 그러므로, 수중터널 지반 접속부의 응력 집중 해소와 공진 방지를 동시에 고려하여 지반 접속부를 설계해야 할 것으로 판단된다.

Keywords

Acknowledgement

본 연구는 2022년도 정부(과학기술정보통신부)의 재원으로 한국연구재단(No. 2017R1A5A1014883)의 지원을 받아 수행되었습니다. 이에 감사드립니다.

References

  1. Cifuentes, C., Kim, S., Kim, M.H., Park, W.S. (2015), "Numerical simulation of the coupled dynamic response of a submerged floating tunnel with mooring lines in regular waves", Ocean Systems Engineering, Vol. 5, No. 2, pp. 109-123. https://doi.org/10.12989/ose.2015.5.2.109
  2. Grant, A.B. (1986), "A submerged floating tunnel solution to a crossing for the Strait of Messina", Proceedings of the Symposium on Strait Crossings, Stavanger, Norway, pp. 365.
  3. Haukas, T., Remseth, S. (1997), "Global dynamic analysis of floating submerged tunnels", Proceedings of the 10th Nordic Seminar on Computational Mechanics, October 24-25, Tallinn, Estonia.
  4. Itasca (2013), FLAC3D: Fast Lagrangian Analysis of Continua in 3 Dimensions, Online Manual, Itasca Consulting Group, U.S. Minneapolis, pp. 175-180.
  5. Jakobsen, B. (2010), "Design of the submerged floating tunnel operating under various conditions", Procedia Engineering, Vol. 4, pp. 71-79. https://doi.org/10.1016/j.proeng.2010.08.009
  6. Jiang, B., Liang, B., Wu, S. (2018), "Feasibility study on the submerged floating tunnel in Qiongzhou strait, China", Polish Maritime Research, Vol. 2, pp. 4-11. https://doi.org/10.2478/pomr-2018-0066
  7. Jin, C., Kim, M.H. (2017), "Dynamic and structural responses of a submerged floating tunnel under extreme wave conditions", Ocean Systems Engineering, Vol. 7, No. 4, pp. 413-433. https://doi.org/10.12989/OSE.2017.7.4.413
  8. Jin, C., Kim, M.H. (2021), "The effect of key design parameters on the global performance of submerged floating tunnel under target wave and earthquake excitations", CMES-Computer Modeling in Engineering & Sciences, Vol. 128, No. 1, pp. 315-337. https://doi.org/10.32604/cmes.2021.016494
  9. Jin, C., Kim, M.H. (2018), "Time-domain hydro-elastic analysis of a SFT (submerged floating tunnel) with mooring lines under extreme wave and seismic excitations", Applied Sciences, Vol. 8, No. 12, 2386.
  10. Jin, R., Gou, Y., Geng, B., Zhang, H., Liu, Y. (2020), "Coupled dynamic analysis for wave action on a tension leg-type submerged floating tunnel in time domain", Ocean Engineering, Vol. 212, 107600.
  11. Kang, S.J., Kim, J.T., Cho, G.C. (2020), "Preliminary study on the ground behavior at shore connection of submerged floating tunnel using numerical analysis", Geomechanics and Engineering, Vol. 21, No. 2, pp. 133-142. https://doi.org/10.12989/gae.2020.21.2.133
  12. Kuhlemeyer, R.L., Lysmer, J. (1973), "Finite element method accuracy for wave propagation problems", Journal of the Soil Mechanics and Foundations Division, Vol. 99, No. 5, pp. 421-427. https://doi.org/10.1061/JSFEAQ.0001885
  13. Long, X., Ge, F., Wang, L., Hong, Y. (2009), "Effects of fundamental structure parameters on dynamic responses of submerged floating tunnel under hydrodynamic loads", Acta Mechacica Sinica, Vol. 25, pp. 335-344. https://doi.org/10.1007/s10409-009-0233-y
  14. Lysmer, J., Kuhlemeyer, R.L. (1969), "Finite dynamic model for infinite media", Journal of the Engineering Mechanics Division, Vol. 95. No. 4, pp. 859-877. https://doi.org/10.1061/JMCEA3.0001144
  15. Martinelli, L., Barbella, G., Feriani, A. (2010), "Modeling of Qiandao Lake submerged floating tunnel subject to multi-support seismic input", Procedia Engineering, Vol. 4, pp. 311-318. https://doi.org/10.1016/j.proeng.2010.08.035
  16. Mazzolani, F.M., Landolfo, R., Faggiano, B., Esposto, M. (2007), "A submerged floating tunnel (Archimedes bridge) prototype in the Qiandao lake (PR of China): research development and basic design", Costruzioni Metalliche, Vol. 5, pp. 45-63.
  17. NPRA (2016), Bjornafjord submerged floating tube bridge: K3/K4 technical report, in: Soreide, T.H. (ed.), Norwegian Public Roads Administration, pp. 121-199.
  18. Sae-Long, W., Limkatanyu, S., Hansapinyo, C., Prachasaree, W., Rungamornrat, J., Kwon, M. (2021), "Nonlinear flexibility-based beam element on Winkler-Pasternak foundation", Geomechics and Engineering, Vol. 24, No. 4, pp. 371-388.
  19. Xiao, J., Huang, G. (2010), "Transverse earthquake response and design analysis of submerged floating tunnels with various shore connections", Procedia Engineering, Vol. 4, pp. 233-242. https://doi.org/10.1016/j.proeng.2010.08.027
  20. Youshi, H., Fei, G. (2010), "Dynamic response and structural integrity of submerged floating tunnel", Procedia Engineering, Vol. 4, pp. 35-50. https://doi.org/10.1016/j.proeng.2010.08.006