Şehir İçerisinde Açılan Tünellerde Portal Şev Stabilitesi ile Tünel Kazı İlişkisine Bir Örnek (T7 Tüneli, Ankara-Sivas Yüksek Hızlı Tren Projesi (Kayaş-Elmadağ Kesimi))

Year 2022, , 1 - 13, 31.07.2022

Ebu Bekir Aygar

https://doi.org/10.47072/demiryolu.1064319

Abstract

Tünellerde portal kesimleri her zaman kritik mühendislik yapıları içerisinde olmuştur. Portal ve tünellerin etkileşimi hem portal tasarımını hem de tünel tasarımını etkilemektedir. Portal şevlerinde olası bir yenilmenin etkisi doğrudan tünelleri etkileyeceğinden tüneldeki ilerlemeleri de olumsuz etkilemekte ve zaman zaman durdurmaktadır. Uzun tünellerde kazı ve destek işlemlerinin yıllarca süreceği göz önüne alındığında portal şevlerinin duraylılığı büyük önem kazanmaktadır. Kaya birimlerinde açılan tünellerde süreksizliklere bağlı olarak gelişecek yenilmeler ile zayıf zeminlerde portal şevlerinde toptan göçme olarak meydana gelen yenilmelerin tahkiki, uzun döneme göre yapılmalıdır. Ayrıca yüzeyde ve portal çevresinde yerleşim alanlarının olduğu durumda ise daha kritik bir durum meydana gelmektedir. Bu çalışma kapsamında, Ankara-Sivas Yüksek Hızlı Tren Projesi (Kayaş-Elmadağ kesimi) T7 tüneli özelinde stabilte problemleri incelenmiştir. Tünel kazısı sırasında meydana gelen deformasyonların etkisi ile tünel stabilitesini yitirmiş ve tünel kazısı durdurulmuştur. Tünel destekleri yenilerek portal stabilitesini de olumsuz etkilemiştir. Ayrıca tünel giriş portal kesiminde yerleşimlerinolması bu durumun önemini daha da artırmıştır. Bu amaçla portal ve tünel destekleri için nümerik analizler yapılarak mevcut durumun stabilitesi değerlendirilmiş sonrasında ise yeni destek sistemleri ile portal kesimi için metodoloji önerilmiştir.

Keywords

Portal stabiltesi, Hızlı tren projesi, Tünel destek sistemi

An Example of the Relationship Between Portal Slope Stability and Tunnel Excavation in the Urban Area-(T7 Tunnel, Ankara-Sivas High Speed Train Project (Kayaş-Elmadağ Section))

Abstract

Portal sections in tunnels have always been within critical engineering structures. The interaction of the portal and tunnels affects both the portal design and the tunnel design. Since the effect of a possible failure in the portal slopes directly affects the tunnels, it also negatively affects the progress in the tunnel and stops it sometimes. Considering that the excavation and support work in long tunnels may take years, the stability of the portal slopes gains great importance. The failures that will develop due to discontinuities in the tunnels excavated in the rock units and the failures that occur as a wholescale collapse in the portal slopes in weak soils should be evaluated according to the long term. In addition, a more critical situation occurs when there are residential areas around the portal. Within the scope of this study, this situation is investigated specifically for the T7 tunnel constructed within the scope of Ankara-Sivas High Speed Train Project, Kayaş-Elmadağ section. With the effect of the deformations that occurred during the tunnel excavation, the tunnel lost its stability and the tunnel excavation was stopped. The tunnel supports were renewed, negatively affecting the stability of the portal. In addition, the fact that there is a settlement in the tunnel entrance portal section has increased the importance of this situation. For this purpose, numerical analyzes were performed for the portal and tunnel supports, and the stability of the current situation was evaluated, and then a methodology was proposed for the portal section with new support systems.

Keywords

Portal stability, High speed train project, Tunnel support system.

References

• [1] L.v Rabcewicz, “The new austrian tunnelling method, Part One,” Water Power, pp 453–457, 1964.
• [2] L.v. Rabcewicz, “The new austrian tunnelling method, Part Two,” Water Power, pp 511–515, 1964.
• [3] L.v. Rabcewicz, “The new austrian tunnelling method, Part Three,” Water Power, pp 19–24, 1965.
• [4] E.B. Aygar, C. Gökçeoğlu, “Ankara-istanbul yüksek hızlı tren projesi, t13 tüneli fay zonunda karşılaşılan sorunlar ve çözüm önerileri ankara-istanbul hıgh speed raılway project, the problems encountered at t13 tunnel fault zone and solutıon suggestıons,” IMCET 2019 / Antalya / Turkey / April 16 . 19, Proceedings 26th International Mining Congress and Exhibition of Turkey, 2019.
• [5] E.B. Aygar, C. Gökçeoğlu, “Problems encountered during a railway tunnel excavation in squeezing and swelling materials and possible engineering measures: a case study from turkey.” Sustainability, 2020, 12, 1166, https://doi.org/10.3390/su12031166, 2020.
• [6] E.B. Aygar, C. Gökçeoğlu, “Evaluation of collapse mechanism and portal interaction of a high-speed railway tunnel (t29 tunnel, turkey),” Eurock 2021, Torino. 2021.
• [7] E.Poşluk, S. Dalgıç, İ. Kuşku, E.A. Poşluk, “Heyelan ıslahında gereken dayanma kuvvetinin limit denge yöntemi ile belirlenmesi,” İstanbul Yerbilimleri Dergisi, C.27, S.2. 77-88, Y.2014, 2017.
• [8] E.B. Aygar, C. Gokceoglu, “Effects of portal failure on tunnel support systems in a highway tunnel”. Geotech Geol Eng 39, 5707–5726.https://doi.org/10.1007/s10706-021-01859-z. 2021
• [9] A. Can, Y. Baskose and C. Gokceoglu, “Stability assessments of a triple-tunnel portal with numerical analysis (south of Turkey)”. Geotechnical Research, https://doi.org/10.1680/jgere.21.00028. 2022
• [10] Karayolları Genel Müdürlüğü, Karayolları Teknik Şartnamesi, 2013.
• [11] L.v. Rabcewicz, J. Golser, “Principles of dimensioning the supporting system for the “new austrian tunnelling method,” Water Power, Marc, 88-93. 1973.
• [12] L. Müller, “Removing misconceptions on the new austrian tunnelling method,” Tunnels & Tunnelling International;10(8):29–32. 1978.
• [13] Yüksel Proje, Kayaş-yerköy demiryolu kesim-1 (km:12+263-74+100) tünel jeoteknik raporu (t1, t2, t3, t4, t5, t6 ve t7), 2011.
• [14] N.R. Barton, R. Lien, J. Lunde, “Engineering classification of rock masses for the design of tunnel support,” Rock Mech. 6(4), 189-239. 1974.
• [15] N. R. Barton, F. Løset, R. Lien, J. Lunde, “Application of the q-system in design decisions,” In Subsurface space, (ed. M. Bergman) 2, 553-561. New York: Pergamon.1981.
• [16] N.Barton, “Application of q-system and index tests to estimate shear strength and deformability of rock masses,” In Workshop on Norwegian Method of Tunnelling (pp. 66–84). New Delhi, India,1993
• [17] Z.T. Bieniawski, “Engineering classification of jointed rock masses,” Trans S. Afr. Inst. Civ. Engrs 15, 335-344. 1973.
• [18] Z.T. Bieniawski, “Rock mass classification in rock engineering,” In Exploration for rock engineering, proc. of the symp., (ed. Z.T. Bieniawski) 1, 97-106. Cape Town: Balkema. 1976.
• [19] Z.T. Bieniawski, Engineering rock mass classifications. New York: Wiley. 1989.
• [20] Fugro Sial, “Ankara-sivas demiryolu projesi kayaş-kırıkkale arası kesim-1 (kayaş-elmadağ) (km:12+263-45+440) Tünel 7 Giriş Portalı Destek Sistemi Hesap Raporu”, 2019
• [21] P. Marinos, E. Hoek, “Gsi: a geologically friendly tool for rock mass strength estimation,” In: Poceedings of the GeıEng2000, International conference on geotechnical and geological engineering, Melbourne, Technomic publishers, Lancaster, pp 1422-1446
• [22] E. Hoek, P. Marinos, “Predicting tunnel squeezing,” Tunnels and Tunnelling International. Part 1 – November 2000, Part 2 – December 2000.
• [23] Roclab, 2011, Version 1.032, www.rocscience.com
• [24] RocScience, 2020. Phase2 8.0 User Guide, [Accessed: 17-Nov-2021]. https://www.rocscience.com/downloads/phase2/ Phase2_ TutorialManual,
• [25] J. Jacky, “The coefficient of earth pressure at rest.” J. Soc. Hung. Archit. Eng. 78, 355–388. 1944.
• [26] U.S. Department of Transportation Federal Highway Administration, Technical manual for design and construction of road tunnels -civil elements, Publication No:FHWA-NHI-10-34, 2009