종방향균열 영향인자 분석을 통한 NATM터널 정밀안전진단 상태평가 항목의 재검토
A re-appraisal of scoring items in state assessment of NATM tunnel considering influencing factors causing longitudinal cracks
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초록
공용중인 터널의 조사 및 평가는 시설물안전법의 안전점검 및 정밀안전진단 세부지침(터널)편에 따라 외관조사와 내구성조사를 근거하여 상태평가를 수행하고 있다. 본 연구에서는 종방향균열의 발생요인 파악을 위해 준공 후 10년이 경과되어 최초 정밀안전진단이 실시된 NATM터널 12개에 대해 균열과 라이닝의 두께를 검토하여, 이를 반영한 상태평가 수정사항을 모색하였다. 종방향균열에 대한 굴착지반의 영향을 검토하기 위해 지보패턴, 이를 구성하는 지보재 시공 조건, 라이닝의 재료적 특성, GPR탐사를 통한 라이닝 두께 등을 터널 형상 및 용도에 따라 4개의 그룹으로 나누어 자료를 분석하였다. 균열발생밀도는 숏크리트, 록볼트, 강지보재의 지보재 지지능력에 따라 변화되나 굴착지보패턴에 따른 균열발생과의 연관성은 낮은 것으로 나타났다. 라이닝 재료적인 특징인 물-시멘트비, 시멘트함유량, 강도 등이 균열발생에 영향을 주는 것으로 나타났다. 또한, GPR탐사의 라이닝 두께를 반영한 상태평가에서는 평균 0.03 정도(분포, 0.001~0.071) 의 점수증가를 야기하는 것으로 확인되어 향후 라이닝 두께 부족을 고려하는 현실적인 상태평가 방안에 대한 검토가 필요하다.
Abstract
State assessment of an operational tunnel is usually done by performing visual inspection and durability tests by following the detailed guideline for safety inspection (SI) and/ or precision inspection for safety and diagnosis (PISD). In this study, 12 NATM tunnels, which have been operational for more than 10 years, were inspected to figure out the cause of longitudinal cracks for the purpose of modifying the scoring items in the state assessment NATM tunnel related to the longitudinal crack and the thickness of concrete lining. All investigated tunnels were classified into four groups depending on the shape and usage of each tunnel. The causes of longitudinal crack occurrence were analyzed by investigating the correlations between the longitudinal crack and the following four factors: the patterns of ground excavation; construction state of primary support system; characteristics of material properties of the concrete lining; and thickness of lining which was obtained by Ground Penetration Radar (GPR) tests. It was found that influencing factors causing longitudinal cracks in the lining were closely related with the construction condition of the primary support system, i.e. shotcrete, rockbolt, and steel-rib; crack occurrences were not much affected by the excavation patterns. As for the properties of concrete lining materials, occurrence of the longitudinal crack was mostly affected by the following three items: w/c ratio; contents of cement; and strength of lining. When estimating the lining thickness of the concrete lining by GPR tests and taking thickness effect into account in the statement assessment, it was concluded that increase of the index score by an average of 0.03 (ranging from 0.01 up to 0.071) is needed; a more realistic way of state assessment should be proposed in which the increased index score caused by lack of lining thickness should be taken into account.
참고문헌 (24)
- Breysse, D., "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", pp.63~262 (2012), Springer
- 추진호, "정밀안전진단 결과를 활용한 NATM (철근)의라이닝 결함 종류별 발생원인 및 분석 - Part I", 한국터널지하공간학회 논문집, 21(1), pp.1~29 (2019), 사단법인 한국터널지하공간학회[DOI]
- 추진호, "정밀안전진단 결과를 활용한 NATM터널(무근)의 라이닝 균열 종류별 발생원인 및 분석 - Part I", 한국터널지하공간학회 논문집, 13(3), pp.199~214 (2011), 사단법인 한국터널지하공간학회
- Health and Safety Executive, "Safety of New Austrian Tunnelling Method (NATM) Tunnels: a review of sprayed concrete lined tunnels with particular reference to London Clay", pp.1~88 (1996), HSE Books
- Hugenschmidt, J., "GPR inspection of concrete bridge", Cement and Concrete Composites, 28(4), pp.384~392 (2006)
- 전중규, "모형 실험에 의한 터널 콘크리트 라이닝의 천단부 균열 제어에 관한 연구", 한국터널지하공간학회 논문집, 8(3), pp.227~235 (2006), 사단법인 한국터널지하공간학회
- Joh, S. H., "Pavement integrity assessed by leaky surface waves with wave group interpretation", Journal of Transportation Engineering, Part B: Pavements, 144(3), pp.04018036-1~04018036-14 (2018)[DOI]
- 김상환, "대단면 터널 라이닝 품질개선을 위한 시공기법에 대한 연구", 한국터널지하공간학회 논문집, 8(1), pp.77~86 (2006), 사단법인 한국터널지하공간학회
- Analysis to the causes of longitudinal crack in NATM road tunnel and its repair and retrofit method, "KISTEC", Korea Infrastructure Safety and Technology Corporation, 1~199 (1997)
- KTA, "Case histories of tunnel collapse", pp.1~420 (2010), CIR
- Lai, J., "Structural safety assessment of existing multiarch tunnel : a case study", Advances in Materials Science and Engineering, 2017, pp.1~11 (2017)
- Lee, D. H., "On mechanical behavior and cracking characteristics of tunnel lining by numerical analysis", Journal of Korean Society For Rock Mechanics, 8(2), pp.146~156 (1998)
- 이유석, "공용중인 3-Arch터널의 열화조사 및 원인분석", 한국터널지하공간학회 논문집, 11(1), pp.97~105 (2009), 사단법인 한국터널지하공간학회
- Maeda, Y., "Study of the evaluation method on tunnel lining crack progress", Proceedings of World Tunnel Congress, pp.1~13 (2018)
- MOLIT, "Detail guideline for safety diagnosis and safety inspection for safety and diagnosis (tunnel)", Korea Infrastructure Safety and Technology Corporation, 1~56 (2017)
- Müller, L., "Reasons for unsuccessful applications of the New Austrian Tunnelling Method", Tunnelling under difficult conditions: Proceedings of the international tunnel symposium, pp.67~72 (1978)
- 박성우, "터널 덕트슬래브의 종방향 균열에 대한 원인 분석 사례 연구", 한국구조물진단유지관리공학회 논문집, 16(5), pp.19~28 (2012), 한국구조물진단유지관리공학회
- Rankoth, C.K., "Investigation of time dependent stress at crown of second lining concrete of NATM tunnels for mitigating longitudinal cracks", Doctoral, pp.2016
- Rankoth, C. K., "Investigation of stresses generated in second lining concrete of NATM tunnels in early age", JCI-Rilem International Workshop (2017)
- Robert, J. F., "Concrete for underground structures-guidelines for design and construction", pp.17~33 (2011), Society for Mining, Metallurgry, and Exploration, Inc
- 서강천, "공용중인 도심지 지하철터널의 변상 원인 규명 및 보강대책에 관한 연구", 석사, 토목공학, pp.2002
- Thomas, A., "Sprayed concrete lined tunnels : an introduction", pp.79~221 (2009), Taylor & Francis
- Wilhelm, H., "Reduction of crack formation in tunnel inner shells made of in-situ concrete", Erschienen in der Zeitschrift Bauingenieur, 3, pp.73~84 (2000)
- 정수매, "NATM 터널라이닝 종방향 균열 제어공법", 한국터널지하공간학회 논문집, 11(4), pp.437~447 (2009), 사단법인 한국터널지하공간학회