Kazı Derinliğinin Püskürtme Beton Dayanımı Üzerindeki Etkisi: Sayısal Bir Yaklaşım

Year 2018, Volume: 8 Issue: 1, 63 - 74, 31.01.2018

Mustafa Kanık , Zülfü Gürocak

https://doi.org/10.17714/gumusfenbil.335028

Abstract

Uygun ve güvenilir destek sistemlerinin seçimi,
tünelcilikte maliyet ve güvenliği etkileyen en önemli faktörlerden birisidir.
Farklı araştırmacılar tarafından önerilmiş olan görgül kaya sınıflama
yöntemleri destek tipinin seçiminde büyük kolaylık sağlamaktadır. Bu konuda
kullanılan diğer bir yöntem sayısal analizlerdir. Görgül olarak elde edilen
destek tipinin sayısal olarak da analiz edilmesi sonucunda daha güvenilir ve
ekonomik destek tipi belirlenebilmektedir. Bu çalışmada, farklı kaya sınıfları
için RMR₈₉ tarafından önerilen püskürtme betonun dayanımı ile kazı
derinliği arasındaki ilişkileri incelemek amacıyla Sonlu Elemanlar Yöntemi
(FEM) kullanılarak sayısal modellemeler yapılmıştır. Modellemelerde, Zayıf,
Orta ve İyi kaliteli kaya sınıfındaki kaya kütleleri ve farklı kazı
derinlikleri dikkate alınmıştır. Kazı derinliğinin artması bağlı olarak, destek
sisteminin yenilmeden çalışabilmesi için püskürtme beton dayanımının ne kadar
olması gerektiği araştırılmıştır. Yapılan analizlere göre püskürtme beton
dayanımının 30 MPa alınması durumda, İyi kaliteli Kaya sınıfında 450 m, Orta
kaliteli Kaya sınıfında 310 m, Zayıf kaliteli Kaya sınıfında ise 200 m kazı
derinliğinde püskürtme betonda yenilmeler meydana gelmektedir. Bu
derinliklerden sonra destek sisteminin duraylı kalabilmesi için püskürtme beton
dayanımının artırılması gerekmektedir. Püskürtme beton dayanımı 40 MPa’ya
çıkarıldığında, İyi kaliteli Kaya sınıfında 530 m, Orta kaliteli Kaya sınıfında
420 m ve Zayıf kaliteli Kaya sınıfında ise 260 m kazı derinliğine kadar destek
elemanlarında yenilme meydana gelmemektedir. İyi kaliteli kaya sınıfında 20 MPa
dayanımlı püskürtme beton için yapılan analizlerde, 410 m örtü kalınlığına
kadar destek sisteminde yenilme meydana gelmemektedir. Bu çalışmadan elde
edilen sonuçlar, kazı derinliğinin artması sonucunda, destek sistemlerinin
yenilmemesi için püskürtme beton dayanımın artırılması veya bir alt kaya sınıfı
için önerilen destek sistemlerinin seçilmesi gerektiğini göstermektedir.

Keywords

Kazı derinliği, RMR sınıflama sistemi, Püskürtme beton dayanımı, FEM analizi

Effect of Excavation Depth on Shotcrete Strength: A Numerical Approach

Abstract

Choosing appropriate and reliable support systems is one of the most
important factors affecting cost and security in tunneling. The empirical rock
classification methods proposed by different researchers provide great
convenience in selecting the support type. Another method used in this regard
is numerical analysis. With the aid of the numerical analyses, analyzing the
support system empirically obtained helps to determine more reliable and economic
support types. In this study, numerical models were developed using Finite
Elements Method (FEM) to investigate the relationship between the strength of
shotcrete and the excavation depth for the different rock classes proposed by
RMR₈₉. Different excavation depths for Weak, Fair and Good rock
masses are taken into account in the modeling. Depending on the increase in
depth of excavation, it has been researched how much the strength of the
shotcrete must be so that the support system can continue to support without
being yielded. According to the evaluated models, when the shotcrete strength
is assumed as 30 MPa, the elements of shotcrete was started to yielded at 200 m
depth for the weak rock mass, 310 m depth for the fair rock mass and 450 m
depth for the good rock mass. After reaching the mentioned depths, it is
necessary to increase the strength of the shotcrete in order to keep the
support system stable. Once the shotcrete strength is increased to 40 MPa,
there was not failure in the support elements up to the excavation depth of 530
m in the good rock mass, 420 m for fair rock mass and 260 m for the weak rock
mass. The support system was determined stable up to 410 m overburden in the
evaluated analyses for 20 MPa strengthen shotcrete. In this study, it is
revealed that, the increase in depth of excavation indicates that the strength
of the shotcrete must be increased to avoid instabilities of the support
systems or that the support systems recommended for a lower rock class should
be selected.

Keywords

Excavation depth, Numerical modeling, RMR classification system, Shotcrete strength

References

• Badr, A, 2016. Statistical Analysis of the Variability in Shotcrete Strength, Global Journal of Researches in Engineering: E Civil And Structural Engineering, Volume 16, Issue 4.
• Badr, A., ve Brooks, J.J., 2008. “Rebound and Composition of in-Situ Polypropylene Fibre-Reinforced Shotcrete,” 11th 6 Intl Conf Durability of Building Materials & Components, 11DBMC, Istanbul, Turkey, 11-14 May, Vol. 1, pp. 569-576.
• Barton, N.R., Lien, R., and Lunde, J., 1974. Engineering classification of rock masses for the design of tunnel support, Rock Mechanics, v. 6, p. 189-239.
• Barros, J.A., Lourenço, L.A., Soltanzadeh, F. And Taheri, M. (2014) “Steel-fibre reinforced concrete for elements failing in bending and in shear,” European Journal of Environmental and Civil Engineering, 31 18(1), pp.33-65.
• Beauprè, D., Dufour,J.F., Hutter, J. ve Jolin, M., 2005. Variability of compressive Strength of Shotcrete in a Tunnel-Lining Project, Shotcrete, V. 5, No. 2, pp.22-25.
• Bieniawski, Z.T., 1973, Engineering classification of jointed rock masses: Transaction of the South African Institution of Civil Engineers, v. 15, p. 335-344.
• Bieniawski, Z.T., 1989. Engineering Rock Mass Classifications. Wiley, 251pp, New York.
• Bieniawski, Z.T., 1993, Classification of rock masses for engineering: The RMR system and future trends, In:Hudson, J.A., ed., Comprehensive Rock Engineering, Volume 3: Oxford, Pergamon Press, p. 553-573, New York.
• Cai, M., Kaiser, P.K., Tasaka, Y. and Minami, M., 2007. Determination of residual strength parameters of jointed rock masses using the GSI system, International Journal of Rock Mechanics and Mining Sciences, 4 (2), 247–265.
• Celada, B., Tardaguila, I., Varona, P., Rodriguez, A. and Bieniawski, Z.T., 2014. Innovating tunnel design by an improved experience-based RMR system. In: World Tunnel Congress, May 9th to 15th 2014, Iguassu Falls, Brazil.
• Deere, D.U., 1964. Technical description of rock cores for engineering purposes, Rock Mech. Rock Eng. 1, 17–22.
• Fenner, R., 1938. Untersuchungen zur Erkenntnis des Gebirgsdrucks, Glückauf, 74, 32, 681-695.
• Genis, M., Basarir, H., Ozarslan, A., Bilir, E. and Balaban, E., 2007. Engineering geological appraisal of the rock masses and preliminary support design, Dorukhan Tunnel, Zonguldak, Turkey. Engineering Geology, 92, 14–26.
• Gurocak, Z., Solanki, P. and Zaman, M.M., 2007. Empirical and numerical analyses of support requirements for a diversion tunnel at the Boztepe dam site, eastern Turkey. Engineering Geology. 91, 194–208.
• Gurocak, Z., 2011. Analyses of stability and support design for a diversion tunnel at the Kapikaya dam site, Turkey, Bulletin of Engineering Geology and the Environment, 70, 41–52.
• Hoek, E., Kaiser, P.K. ve Bawden, W.H., 1995. Support of Underground Excavations in Hard Rock. Rotterdam, Balkema Hoek, E., 2007, Practical rock engineering, RocScience.
• ISRM, (International Society for Rock Mechanics), 1981. ISRM Suggested Methods: Rock Characterization, Testing and Monitoring, Pergamon Press, London, 211 s.
• Kaya, A., Bulut, F., Alemdag, S., ve Sayın, A. (2011). Analysis of support requirements for a tunnel portal in weak rock: A case study in Turkey. Scientific Research and Essays, 6(31), 6566–6583.
• Kaya, A. ve Bulut, F. (2013). Stability analyses of tunnels excavated in weak rock masses using empirical and numerical methods, Jeoloji Mühendisliği Dergisi, 37(2), 103–116.
• Kaya, A., and Sayın, A. (2017) Engineering geological appraisal and preliminary support design for the Salarha Tunnel, Northeast Turkey. Bull Eng Geol Environ, DOI: 10.1007/s10064-017-1177-2
• Kanik, M., Gurocak, Z. and Alemdag, S., 2015. A comparison of support systems obtained from the RMR89 and RMR14 by numerical analyses: Macka Tunnel project, NE Turkey, Journal of African Earth Sciences,Volume 109, September 2015, 224–238.
• Kirsten, 1992. Comparative efficiency and ultimate strength of mesh- and fibre reinforced shotcrete as determined from full-scale bending tests, Journal of the South African Institute of Mining and Metallurgy, Nov., 303-322.
• KGM (Karayolları Genel Müdürlüğü), 2013. NATM Uygulamalı Yeraltı Tünel İşleri Teknik Şartnamesi, Karayolları Genel Müdürlüğü, Ankara.
• Lauffer, H., 1958, Gebirgsklassifizierung für den Stollenbau: Geology Bauwesen, v. 24, p. 46-51.
• Mohajerani, A., Rodrigues, D., Ricciuti,C., ve Wilson, C., 2015. Early-Age Strength Measurement of Shotcrete, Journal of Materials, Vol 2015, pp 1-10.
• NIOSH, 2014. Shotcrete design and installation compliance testing: early strength, load capacity, toughness, adhesion strength, and applied quality,” Martin et al. edit, National Institute for Occupational Safety and Health, Publication No. 2015-107, RI 9697.
• Palmström, A., 1995. RMi-a rock mass characterization system for rock engineering purposes. Ph.D. thesis, Univ. Of Oslo, Norway, 400 pp
• Patel, P.A., Desai, A.K., ve Desai, K.A., 2012. Evaluation of engineering properties for polypropylene fiber reinforced concrete, International Journal of Advanced Engineering Technology, 3(1), pp.42-45.
• Rocscience, 2006. Roclab bilgisayar programı, www.rocscience.com
• Rocscience Inc, 2011. Phase2 v8.0 Finite Element Analysis for Excavations and Slopes, Rocscience Inc., Toronto, Ontario, Canada.
• Sheorey, P.R., Murali, M.G., Sinha, A., 2001. Influence of elastic constants on the horizontal in situ stress. Int. J. Rock Mech. Min.Sci. 38 (1), pp 1211–1216.
• Stini, I., "Tunnelbaugeologie," Springer-Verlaa, Vienna, 1950, p 336.
• Terzaghi, K., 1946, Rock defects and loads on tunnel supports, in Proctor, R.V., and White, T.L., eds., Rock tunneling with steel support, Volume 1: Youngstown,Ohio, Commercial Shearing and Stamping Company p. 17-99.
• Wickham, G.E., Tiedemann, H. R. and Skinner, E. H., 1972, Support determination based on geologic predictions, In: Lane, K.S.a.G., L. A., ed., North American Rapid Excavation and Tunneling Conference: Chicago, New York: Society of Mining Engineers of the American Institute of Mining, Metallurgical and Petroleum Engineers, p. 43-64.
• Wood, D.F., Banthia, N. ve Trottier, J-F, 1993. A comparative study of different steel fibres in shotcrete. In Shotcrete for underground support VI, Niagara Falls, 57- 66. New York: Am. Soc. Civ. Engrs
• Yalcin, E., Gurocak, Z., Ghabchi, R. ve Zaman, M, 2016. Numerical Analysis for a Realistic Support Design: Case Study of the Komurhan Tunnel in Eastern Turkey, International Journal of Geomechanics, Vol 16(3)
• Zhang, L. 2014, Variability of Compressive Strength of Shotcrete in a Tunnel-Lining Project. www.shotcrete.org