China Safety Science Journal ›› 2025, Vol. 35 ›› Issue (5): 186-194.doi: 10.16265/j.cnki.issn1003-3033.2025.05.1523

• Safety engineering technology • Previous Articles     Next Articles

Performance assessment of diseased tunnels based on FRP-PCM reinforcement

XU Zhenyu1,2(), ZHANG Xuepeng1,2,**(), LI Ningbo3, JIANG Yujing1,4, CHEN Hongbin4, LIU Linsheng5   

  1. 1 State Key Laboratory of Disaster Prevention and Ecology Protection in Open-pit Coal Mines, Shandong University of Science and Technology, Qingdao Shandong, 266590, China
    2 College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao Shandong, 266590, China
    3 General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing 100120, China
    4 School of Engineering, Nagasaki University, Nagasaki 8528521, Japan
    5 Qingdao Metro Group Co., Ltd., Qingdao Shandong 266555, China
  • Received:2025-01-15 Revised:2025-03-18 Online:2025-05-28 Published:2025-11-28
  • Contact: ZHANG Xuepeng

Abstract:

In order to enhance the safety and operational maintenance capabilities of tunnels, a quantitative evaluation framework and design methodology for FRP-PCM composite reinforcement in diseased tunnels was established through cross-sectional ultimate bearing capacity analysis. Numerical tests were conducted using the finite difference method to analyze the stability of FRP-PCM-reinforced diseased tunnels. Tunnel safety assessment was performed based on the sectional ultimate bearing capacity curve, commonly referred to as the M-N curve. A safety factor α of the M-N curve was proposed to enable a quantitative evaluation of the reinforcement effect. Based on this framework, a design and selection scheme for FRP was established, incorporating tunnel design specifications. The analysis reveals that when cavities exist at the crown of the tunnel, both the crown and shoulders exhibit higher risk levels according to the M-N curve. Furthermore, under conditions of poorer surrounding rock quality, greater lining concrete deterioration, and increased loosening pressure height, the reinforcing effect of the FRP-PCM method becomes more significant. For cases with an 80% degradation degree, Class V surrounding rock, and a loosened pressure height of 2D, the application of different types of FRP reinforcement reduces the safety factor of the M-N curve by 23%-32%, thereby significantly improving the structural safety of the lining. By leveraging the M-N curve's safety coefficient, an appropriate FRP type can be selected for defective lining reinforcement based on factors such as rock quality, loose pressure height, and lining conditions.

Key words: diseased tunnel, fiber-reinforced polymer cement mortar (FRP-PCM), reinforcement, M-N curve, lining diseases

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