Stability Analysis of Intersection Resulted from Slope and Access Tunnels in Tabas Coal Mine using Finite Difference Numerical Method

Document Type : Research Article

Authors

Dept. of Mining Engineering, Amirkabir University of Technology, Tehran, Iran

Abstract

The demand for underground infrastructures has increased significantly in recent decades due to urbanization, industrial needs, and mineral extraction. In coal mining, the design and construction of intersecting tunnels, especially bifurcated intersections, pose unique challenges. These intersections are often subject to complex stress redistribution, displacement, and plastic deformation. Failure to address these conditions can jeopardize the overall stability and safety of the mining operation.
This study presents a numerical investigation into the stability of a bifurcated tunnel intersection (H16) in the Parvadeh coal mine, Tabas, South Khorasan, Iran. The intersection, formed by S2 slope tunnel and MG5 access tunnel, is situated at a depth of 570 m, within a geologically complex and mechanically heterogeneous rock mass. The Finite Difference Method (FDM), implemented in FLAC3D, was used to model excavation sequences, stress redistribution, plastic deformation, and the effectiveness of proposed support systems. A sensitivity analysis examined the influence of critical geotechnical parameters. Results highlighted key areas of instability, optimal reinforcement strategies, and practical implications for mine design. Field validation also confirms the reliability of the numerical model.

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References

[1]                 Chortis, F., & Kavvadas, M. Three-Dimensional Numerical Analyses of Perpendicular Tunnel Intersections. Geotechnical and Geological Engineering, 39(3), 1771-1793. (2020)
[2]                 Tan, Z., Zhou, Z., Kong, H., Zhao, B., & Zhao, J. Single excavation face method for super-large-span bifurcated tunnels. Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 1-13. (2021)
[3]                 Wang, J., Cao, A., Li, Z., et al. Mechanical Behavior and Excavation Optimization of a Small Clear-Distance Tunnel in an Urban Super Large and Complex Underground Interchange Hub. Applied Sciences, 13(1). (2022)
[4]                 Singh, R. N., Porter, I., & Hematian, J. Finite element analysis of three-way roadway junctions in longwall mining. International Journal of Coal Geology, 45(2-3), 115-125. (2001)
[5]                 Hsiao, F. Y., Wang, C. L., & Chern, J. C. Numerical simulation of rock deformation for support design in tunnel intersection area. Tunnelling and Underground Space Technology, 24(1), 14-21. (2009)
[6]                 Liu, X., & Wang, Y. Three Dimensional Numerical Analysis of Underground Bifurcated Tunnel. Geotechnical and Geological Engineering, 28(4), 447-455. (2010)
[7]                 Guo, Z., Shi, J., Wang, J., Cai, F., & Wang, F. Double-directional control bolt support technology and engineering application at large span Y-type intersections in deep coal mines. Mining Science and Technology (China), 20(2), 254-259. (2010)
[8]                 Li, G., He, M., Zhang, G., & Tao, Z. Deformation mechanism and excavation process of large span intersection within deep soft rock roadway. Mining Science and Technology (China), 20(1), 28-34. (2010)
[9]                 Lin, P., Zhou, Y., Liu, H., & Wang, C. Reinforcement design and stability analysis for large-span tailrace bifurcated tunnels with irregular geometry. Tunnelling and Underground Space Technology, 38, 189-204. (2013)
[10]             Nik, M. G., & Farahani, A. F. Assessment the Stability of Tunnels in Y Shaped Intersections with Regard to the Intersection Angles, Case Study: Penstock Tunnels of Rudbar Dam. Amirkabir Journal of Civil Engineering, 48(2). (2016)
[11]             Golshani, A., Joneidi, M., & Majidian, S. 3D numerical modeling for construction of tunnels intersections- case study of Hakim tunnel. Japanese Geotechnical Society Special Publication, 2(43), 1523-1527. (2016)
[12]             Liu, H.-l., Li, S.-c., Li, L.-p., & Zhang, Q.-q. Study on deformation behavior at intersection of adit and major tunnel in railway. KSCE Journal of Civil Engineering, 21(6), 2459-2466. (2017)
[13]             Zhou, D., Ding, W., Xie, D., & Chen, S. Reinforcement Analysis of Bifurcated Highway Tunnels with Large Section of Different Surrounding Rock Grades in Tiger Leaping Gorge. IOP Conference Series: Materials Science and Engineering, 741(1). (2020)
[14]             Gkikas, V. I., & Nomikos, P. P. Primary Support Design for Sequentially Excavated Tunnel Junctions in Strain-Softening Hoek–Brown Rock Mass. Geotechnical and Geological Engineering, 39(3), 1997-2018. (2020)
[15]             Xie, S., Wu, Y., Chen, D., Liu, R., Han, X., & Ye, Q. Failure analysis and control technology of intersections of large-scale variable cross-section roadways in deep soft rock. International Journal of Coal Science & Technology, 9(1). (2022)
[16]             Xu, H., Zhang, Y., Yang, J., et al. Study on the Constant Resistance Coupling Support Technology for Rock Column at the Intersection Point of Deep Soft Rock Large Section Roadway: A Case Study in China. Shock and Vibration, 2022, 1-12. (2022)
[17]             Sun, X.-m., Qi, Z.-m., Zhang, Y., Miao, C.-y., Zhao, C.-w., & He, M.-c. Failure mechanism and control countermeasures of surrounding rock at deep large section chamber intersection in the Wanfu Coal Mine. Journal of Mountain Science, 20(7), 2058-2075. (2023)
[18]             Jiang, J., Tao, R., Hesham El Naggar, M., Liu, H., & Du, X. Seismic performance and vulnerability analysis for bifurcated tunnels in soft soil. Computers and Geotechnics, 167. (2024)
[19]             (IRITEC), (2003). Tabas Coal Mine Project, detailed design report (Vol. 1, pp. 464).
[20]             Mahdevari, S., Shahriar, K., Sharifzadeh, M., & Tannant, D. D. Stability prediction of gate roadways in longwall mining using artificial neural networks. Neural Computing and Applications, 28(11), 3537-3555. (2016)
[21]             Tabas engineering technical. office. (2023). engineering report.

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History

  • Receive Date: 21 October 2024
  • Revise Date: 27 May 2025
  • Accept Date: 28 May 2025

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