Understanding Tunnel Lining Deformations: The Influence of Cover Depth on Structural Behaviour

Year 2025, Volume: 5 Issue: 4, 234 - 244, 30.12.2025

Sedef Ergenç , Sinem Bozatlı Kartal , Yavuz Abut

https://doi.org/10.64808/engineeringperspective.1792022

Abstract

As cities continue to expand, the demand for effective underground infrastructure to address urban transportation challenges has increased. Tunnels, particularly those constructed using the New Austrian Tunneling Method (NATM), play a crucial role in managing these challenges. This study investigates the deformation behaviors of NATM tunnels under three different cover depths (17 m, 26 m, and 56 m) using the Finite Element Model (FEM) under static loading conditions. The main objective is to analyze the impact of varying cover loads on the stability and structural integrity of egg-shaped tunnel geometries, which are commonly preferred by designers. The analysis investigates deformations during excavation, focusing on both tunnel convergence and surface settlement, in a four-layered ground profile consisting of weathered soil, weathered rock, soft rock, and hard rock, respectively. By comparing these deformations under different cover loads, this study highlights critical factors influencing tunnel design and provides valuable insights for ensuring the safety and efficiency of shallow tunnel construction, particularly in multi-layered rock formations. Key findings indicate a maximum vertical displacement of -11.50 mm at the top of the final lining and a maximum compressive thrust of 155 t/m in the deepest case, demonstrating a non-linear structural response to increasing cover depth. The results, supported by graphical representations, demonstrate the importance of precise cover load calculations in tunnel stability and contribute to the development of engineering guidelines for similar projects.

Keywords

Cover depth , Egg-shaped tunnel , Finite element analysis , Multi-layered rock formations , New Austrian Tunneling Method (NATM) , Tunnel deformation.

Ethical Statement

Authors declare that there is no conflict of interests regarding the publication of the paper.

Thanks

We would like to express our sincere gratitude to Comtec Research for providing access to the trial version of the TUNAPLUS Analysis Program, which was instrumental in performing the finite element analysis for our tunnel design study.

References

• 1. Kumar, P., & Kumar Shrivastava, A. (2022). Experimental and nu-merical analysis of deformation behaviour of tunnels under static loading conditions. Sustainable Energy Technologies and Assess-ments, 52, 102057. https://doi.org/10.1016/j.seta.2022.102057
• 2. Adlım, K. N., Bozatlı, S., & Abut, Y. (2022). Tünel Geometrisinin Deformasyonlar Üzerindeki Etkisinin Sığ ve Tabakalı Kaya Ortamın-da İncelenmesi [Investigation of the Effect of Tunnel Geometry on Deformations in Shallow and Stratified Rock Formation]. Yüzüncü Yıl Üniversitesi Fen Bilimleri Enstitüsü Dergisi, 27(3), 548-556. https://doi.org/10.53433/yyufbed.1090576
• 3. Narunat, H., Pornkasem, J., Prateep, L., & Suchatvee, S. (2016). Investigation on Tunnel Responses Due to Adjacent Loaded Pile By 3D Finite Element Analysis. GEOMATE Journal, 12(31), 63-70. http://dx.doi.org/10.21660/2017.31.6542
• 4. Külekçi, G. (2022). The relation of the method used in tunneling op-erations with the geological structure example of the Black Sea Coastal Road. Journal of Civil Engineering and Construction, 11(4), 255-263. https://doi.org/10.32732/jcec.2022.11.4.255
• 5. Ahmed, M., & Iskander, M. (2012). Evaluation of tunnel face stabil-ity by transparent soil models. Tunnelling and Underground Space Technology, 27(1), 101-110. https://doi.org/10.1016/j.tust.2011.08.001
• 6. Kumar, P., & Shrivastava, A. (2019). Stability of single tunnel in rock under static loading conditions. INDOROCK-2019: 8th Indian Rock Conference, India International Centre, New Delhi.
• 7. Kumar, P., & Shrivastava, A. K. (2021). Physical Investigation of Deformation Behaviour of Single and Twin Tunnel under Static Loading Condition. Applied Sciences, 11(23). https://doi.org/10.3390/app112311506
• 8. Mishra, S., Rao, K. S., Gupta, N. K., & Kumar, A. (2017). Damage to Shallow Tunnels under Static and Dynamic Loading. Procedia En-gineering, 173, 1322-1329. https://doi.org/10.1016/j.proeng.2016.12.171
• 9. Mishra, S., Rao, K. S., Gupta, N. K., & Kumar, A. (2018). Damage to shallow tunnels in different geomaterials under static and dynamic loading. Thin-Walled Structures, 126, 138-149. https://doi.org/10.1016/j.tws.2017.11.051
• 10. Akutagawa, S., Lee, J., Doba, N., Kitagawa, T., Isogai, A., & Matsu-naga, T. (2006). Identification and prediction of deformation behavior around a shallow NATM tunnel using strain softening model. Tun-nelling and Underground Space Technology incorporating Trenchless Technology Research, 21, 387-387. https://doi.org/10.1016/j.tust.2005.12.198
• 11. Golshani, A., Joneidi, M., & Majidian, S. (2016). 3D numerical modeling for construction of tunnels intersections-case study of Ha-kim tunnel. Japanese Geotechnical Society Special Publication, 2(43), 1523-1527. https://doi.org/10.3208/jgssp.IRN-15
• 12. Rehman, H., Naji, A. M., Ali, W., Junaid, M., Abdullah, R. A., & Yoo, H.-k. (2020). Numerical evaluation of new Austrian tunneling method excavation sequences: A case study. International Journal of Mining Science and Technology, 30(3), 381-386. https://doi.org/10.1016/j.ijmst.2020.03.009
• 13. Aygar, E. B. (2020). Evaluation of new Austrian tunnelling method applied to Bolu tunnel's weak rocks. Journal of Rock Mechanics and Geotechnical Engineering, 12(3), 541-556. https://doi.org/10.1016/j.jrmge.2019.12.011
• 14. Alemdag, S., Zeybek, H. I., & Kulekci, G. (2019). Stability evalua-tion of the Gümüşhane-Akçakale cave by numerical analysis method. Journal of Mountain Science, 16(9), 2150-2158. https://doi.org/10.1007/s11629-019-5529-1
• 15. Franco F, J., Viveros M, F., & Viscarra A, F. (2022). Displacements and Stability Assessment in the Portal of Tunnel 3, “El Sillar”, Through the Finite Element Method. Revista Investigación & Desar-rollo, 22(1). https://doi.org/10.23881/idupbo.022.1-8i
• 16. Wijaya, W., Rahardjo, P. P., & Lim, A. (2021). Investigation of Twin Tunnel Deformation with Umbrella Grouting Protection & NATM Tunneling using 3D Finite Element: Case Study Cisumdawu Tunnel. UKaRsT, 5(2), 252-267. https://doi.org/10.30737/ukarst.v5i2.1977
• 17. Kota, V. K., Juneja, A., Bajpai, R. K., & Srivastava, P. (2021, 2021//). Stability Assessment of Cross-Tunnels in Jointed Rock Using Dis-crete Element Method. Proceedings of the Indian Geotechnical Con-ference 2019, Singapore. https://doi.org/10.1007/978-981-33-6466-0_61
• 18. Li, J. K., & Wang, Y. B. (2014). The Surface Deformation Law with Engineering Mechanics Caused by Construction of Tunnels with Large Section and Small Interval. Advanced Materials Research, 886, 440-443. https://doi.org/10.4028/www.scientific.net/AMR.886.440
• 19. Berdoudi, S., Morsli, M., Mekti, Z., & Benselhoub, A. (2022). Nu-merical study on deformation around underground mining structures (Algeria). Natsional'nyi Hirnychyi Universytet. Naukovyi Visnyk(6), 47-51. https://doi.org/10.33271/nvngu/2022-6/047
• 20. Imteyaz, W., & Mishra, S. (2023). Stability Analysis of the Shallow Tunnel Under Soft Ground Regime. Materials Today: Proceedings, 87, 152-158. https://doi.org/10.1016/j.matpr.2023.03.218
• 21. Boldini, D., Lackner, R., & Mang Herbert, A. (2005). Ground-Shotcrete Interaction of NATM Tunnels with High Overburden. Journal of Geotechnical and Geoenvironmental Engineering, 131(7), 886-897. https://doi.org/10.1061/(ASCE)1090-0241(2005)131:7(886)
• 22. Akutagawa, S., Lee, J.-H., & Kitani, T. (2008). Numerical Modeling of Nonlinear Deformation Behavior of Shallow Tunnel by Strain-Softening Analysis. Journal of the Society of Materials Science, Ja-pan, 57(2), 191-198. https://doi.org/10.2472/jsms.57.191
• 23. Chen, C. J., & Zhu, H. L. (2015, 2015/07). Simulation of Train Load on Deformation of Big-Diameter Shield Tunnel. Proceedings of the 2015 International Conference on Electrical, Automation and Me-chanical Engineering. https://doi.org/10.2991/eame-15.2015.173
• 24. Erbeyoğlu, E., Keskin, S. N., Uzundurukan, S., & Akan, R. (2017). Bahçe-Nurdağ (Fevzipaşa) Varyantı Tünel Geçişi Yapısal Tasarımı İncelemesi. Harran Üniversitesi Mühendislik Dergisi, 2(3), 47-56.
• 25. Busby, J., & Marshall, C. (2000). Design and construction of the Øresund tunnel. Proceedings of the Institution of Civil Engineers - Civil Engineering, 138(4), 157-166. https://doi.org/10.1680/cien.2000.138.4.157
• 26. Aygar, E. B., & Gökçeoğlu, C. (2020). Zayıf Zeminlerde Açılan Büyük Çaplı Bir Tünelin Destek Sistemi Tasarımı (Çukurçayır-2 Tü-neli, Trabzon). MT Bilimsel(18), 97-118.
• 27. Ha, S.-g., Naji, A. M., Rehaman, H., Nam, K.-m., Kim, H.-e., Park, J.-w., & Yoo, H.-k. (2021). Expanded Longitudinal Deformation Profile in Tunnel Excavations Considering Rock Mass Conditions via 3D Numerical Analyses. Applied Sciences, 11(12). https://doi.org/10.3390/app11125405
• 28. Töyrä, J. (2006). Behaviour and stability of shallow underground constructions (Publication Number 1402-1757). PhD Thesis, Luleaa University of Technology, Department of Applied Physics and Me-chanical Engineering.
• 29. Karaoğlan, H. (2002). Kaya zeminde tunel tasarımı (Tunnel design in rock) (Publication Number 127018). MSc Thesis, Istanbul Technical University, Graduate School of Science Engineering and Technology. (In Turkish).
• 30. Wyllie, D. C., & Mah, C. (2017). Rock Slope Engineering (4th ed.). CRC Press. https://doi.org/10.1201/9781315274980
• 31. Wyllie, D. C., & Mah, C. W. (2004). Rock strength properties and their measurement. In Rock Slope Engineering (4th ed., pp. 35). CRC Press.
• 32. Ding, W., Shen, Y., Ding, W., Guo, Y., Qiao, Y., & Tang, J. (2025). Stochastic Finite Element-Based Reliability Analysis of Construction Disturbance Induced by Boom-Type Roadheaders in Karst Tunnels. Applied Sciences, 15(21). https://doi.org/10.3390/app152111789