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

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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Assessment of NATM tunnel lining thickness and its behind state utilizing GPR survey

GPR탐사를 통한 NATM터널(무근)라이닝의 두께 분포 및 배면상태 평가

  • Choo, Jin-Ho (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Yoo, Chang-Kyoon (Technical Support in Diagnosis Division, Korea Infrastructure Safety and Technology Cooperation) ;
  • Oh, Young-Chul (Technical Support in Diagnosis Division, Korea Infrastructure Safety and Technology Cooperation) ;
  • Lee, In-Mo (School of Civil, Environmental and Architectural Engineering, Korea University)
  • 추진호 (고려대학교 건축사회환경공학부) ;
  • 유창균 (한국시설안전공단 기술진단지원팀) ;
  • 오영철 (한국시설안전공단 기술진단지원팀) ;
  • 이인모 (고려대학교 건축사회환경공학부)
  • Received : 2019.07.25
  • Accepted : 2019.08.21
  • Published : 2019.09.30
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Abstract

In this study, lining thickness distribution and its behind state (particularly, its void state) were analyzed using the GPR survey data performed on three currently operating NATM tunnels. Results of GPR analysis showed that void areas were mostly detected between concrete lining and primary support, particularly, near the crown of the tunnels. The lining thickness in the left-hand side of the tunnel was different from that of the right-hand side by 8.6~253.5 mm when measured in transverse direction. It was also found that longitudinal cracks were prevailed in the area lining thickness was sharply changed. Longitudinal thickness distribution at the crown was also studied and tested by performing 3 goodness-of-fit tests in order to find the most suitable thickness distribution. Normal distribution (or similar distribution) fit most suitably to the measured data if the measured average thickness was larger than designed one; Gamma and/or Inverse Gauss distribution fit to the measured data reasonably well if the measured average thickness was less than the designed value of thickness. Since actual lining thickness can be a potential index when assessing the state and safety of the unreinforced NATM tunnel lining, measuring of the lining thickness with GPR survey might be needed rather than assuming the thickness is always constant and same with the designed value.

본 연구에서는 3개의 공용중인 NATM터널에서 수행된 정밀안전진단 GPR탐사 결과로 라이닝 두께분포 및 배면상태 특성을 분석하였다. 라이닝 천장에서 실시한 GPR 자료분석으로 라이닝 콘크리트와 1차지보재 사이에 공간이 대부분 존재하는 것으로 분석되었다. 다수의 라이닝 종단탐사로 분석된 횡단 두께의 좌 우 불균형은 8.6~253.5 mm로 확인되었으며 급격한 두께편차 주변에서 종방향균열 발생을 확인하였다. 라이닝 천단 중앙에서 실시된 종단 두께 분포는 3개의 적합도 검증을 통해 터널별 최적의 분포함수가 선정되었다. 종방향 라이닝 두께의 평균이 설계기준 이상인 경우 정규분포 및 이와 유사한 분포 특성을 나타내고 있으며, 설계두께 이하의 터널에서는 Gamma, Inverse Gauss분포함수가 해당터널의 라이닝을 대표하기 위한 최적함수로 적합할 것으로 판단하였다. NATM터널(무근) 라이닝의 두께분포는 터널의 상태평가 및 안전성평가를 전반적으로 분석하기 위한 중요한 지표가 될 수 있으며, 향후 기존의 일정한 설계 두께를 적용하기 보다는 GPR탐사를 반영한 라이닝의 현실적인 평가 방법의 연구가 필요할 것으로 판단된다.

Keywords

References

  1. Ansell, A. (2010), "Investigation of shrinkage cracking in shotcrete on tunnel drains", Tunnelling and Underground Space Technology, Vol. 25, No. 5, pp. 607-613. https://doi.org/10.1016/j.tust.2010.04.006
  2. Basaligheh, F., Keyhani, A. (2015), "Application of tests of goodness of fit in determining the probability density function for spacing of steel sets in tunnel support system", International Journal of Mining and Geo-engineering, Vol. 49, No. 2, pp. 187-203.
  3. Bian, K., Liu, J., Xiao, M., Liu, Z. (2016), "Cause investigation and verification of lining crack of bifurcation tunnel at Huizhou pumped storage power station", Tunnelling and Underground Space Technology, Vol. 54, pp. 123-134. https://doi.org/10.1016/j.tust.2015.10.030
  4. Bjureland, W., Spross, J., Johansson, F., Prastings, A., Larsson, S. (2017), "Reliability aspects of rock tunnel design with the observational method", International Journal of Rock Mechanics and Mining Sciences, Vol. 98, pp. 102-110. https://doi.org/10.1016/j.ijrmms.2017.07.004
  5. Choo, J.H., Park, S.W., Kim, H.T., Jee, K.H., Yoon, T.G. (2011), "Analysis and cause of occurrence of lining cracks on NATM tunnel based on the precise inspection for safety and diagnosis - Part I", Journal of Korean Tunnelling and Underground Space Association, Vol. 13, No. 3, pp. 199-214. https://doi.org/10.9711/KTAJ.2011.13.3.199
  6. Choo, J.H., Yoo, C.K., Oh, Y.C., Lee, I.M. (2019), "A re-appraisal of scoring items in state assessment of NATM tunnel considering influencing factors causing longitudinal cracks", Journal of Korean Tunnelling and Underground Space Association, Vol. 21, No. 4, pp. 479-499. https://doi.org/10.9711/KTAJ.2019.21.4.479
  7. Carranza-Torres, C., Diederichs, M. (2009), "Mechanical analysis of circular liners with particular reference to composite supports. For example, liners consisting of shotcrete and steel sets", Tunnelling and Underground Space Technology, Vol. 24, No. 5, pp. 506-532. https://doi.org/10.1016/j.tust.2009.02.001
  8. Denys, B. (2012), Non-Destructive assessment of concrete structures: reliability and limits of single and combined techniques-state-of-the-art-report of the RILEM technical committee 207-INR, Springer, France, pp. 63-262.
  9. Duracrete (2000), Statistical quantification of the variables in the limit state function: european union-brite euram III, CUR, pp. 1-130.
  10. Haldar, A., Mahadevan, S. (2000), Probability, reliability and statistical methods in engineering design, John Wiley & Sons, Inc., New York, pp. 1-304.
  11. Haack, A., Schreyer, J., Jackel, G. (1995), "State-of-the-art of non-destructive testing methods for determining the state of a tunnel lining", Tunnelling and Underground Space Technology incorporating Trenchless Technology Research, Vol. 10, No. 4, pp. 413-431. https://doi.org/10.1016/0886-7798(95)00030-3
  12. Joh, S.H., Rahman, N.A., Magno, K. (2018), "Pavement integrity assessed by leaky surface waves with wave group interpretation", Journal of Transportation Engineering, Part B: Pavements, Vol. 144, No. 3, pp. 04018036-1-14. https://doi.org/10.1061/JPEODX.0000067
  13. KSCE (2015), Study of the effect of backfilling in tunnel lining, pp. 1-158.
  14. Lateef, A.M. (2011), Analysis of the common defects on in-service urban tunnels and repairing effects, Doctoral Thesis, Chongqing University, pp. 1-156.
  15. Lee, Y.S., Park, S.W, Whang, I.B., Shin, Y.S., Kim, S.G. (2009), "Analysis of cause and deterioration about using 3-arch tunnel", Journal of Korean Tunnelling and Underground Space Association, Vol. 11, No. 1, pp. 97-105.
  16. Lee, K.H., Heo, I.W., Kim, D.H., Lee, I.M. (2011), "The construction management of tunnel using 3D laser scanner", Journal of Korean Tunnelling and Underground Space Association, Vol. 13, No. 3, pp. 159-176. https://doi.org/10.9711/KTAJ.2011.13.3.159
  17. MOLIT (2016), Korean design standard: KCS 27 40 05, pp. 1-8.
  18. Oreste, P.P. (2007), "A numerical approach to the hyperstatic reaction method for the dimensioning of tunnel supports", Tunnelling and Underground Space Technology, Vol. 22, No. 2, pp. 185-205. https://doi.org/10.1016/j.tust.2006.05.002
  19. Park, J.J., Shin, J.C., Hwang, J.H., Lee, K.H., Seo, H.J., Lee, I.M. (2012a), "Assessment of over / underbreak of tunnel utilizing BIM and 3D laser scanner", Journal of Korean Tunnelling and Underground Space Association, Vol. 14, No. 4, pp. 437-451. https://doi.org/10.9711/KTAJ.2012.14.4.437
  20. Park, S.W., Park, S.S., Hwang, I.B., Cha, C.J. (2012b), "A case study on cause analysis for longitudinal crack of duct slab in tunnel", Journal of the Korea Institute for Structural Maintenance and Inspection, Vol. 16, No. 5, pp. 19-28. https://doi.org/10.11112/jksmi.2012.16.5.019
  21. Pottler, R. (1993), "Die unbewehrte innenschale im Felstunnelbau - Standsicherheit und Verformung im Rissbereich", Beton-und Stahlbetonbau, Vol. 88, No. 6, pp. 155-160. https://doi.org/10.1002/best.199300230
  22. Yang, J.S., Fu, J.Y. (2015), "Investigation and rehabilitation of lining imperfections and cracks in an operating railway tunnel", Proceedings of the Engineering Conference International Digital Achives - Shotcrete for Underground Support XII, October, Singapore, pp. 1-10.
  23. Williams, N.D. (2014), Nondestructive testing of rail tunnel linings, Master of Science Thesis, Texas A&M University, pp. 1-100.