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<p>Prestressed composite linings are increasingly adopted in large-diameter tunnels subjected to high internal pressures and complex geological conditions due to their superior structural performance and long-term durability. This work presents a finite element model based on the stratum–structure method to systematically evaluate the influence of interface treatment methods—namely, cushion layers and reinforcing bars—on internal pressure distribution and joint load-bearing behavior. The analysis also considers the effects of surrounding rock weathering and backfill stiffness on the interaction between the lining and the surrounding rock. The results show that the laying area of cushion layers has a negligible effect on pressure distribution, whereas higher stiffness significantly facilitates earlier contact between the inner and outer linings, enabling joint bearing at lower internal pressures and reducing the load on the inner lining. For reinforcing bars, the layout range and density substantially affect the pressure contribution mechanism, while bar diameter has a limited impact. A greater installation angle accelerates the transition from separate to joint bearing. Higher surrounding rock strength leads to a greater internal pressure contribution from the rock, resulting in a more favorable load path, particularly in later loading stages. The influence of backfill stiffness is stage-dependent: from 0 to 1.6&#xa0;MPa, increased stiffness enhances initial rock support; from 1.6 to 2.3&#xa0;MPa, it significantly improves joint action; beyond 2.3&#xa0;MPa, a stiffer backfill helps suppress stress concentration in the lining, reduces cracking risk, and maintains a higher load share for the rock. These findings provide engineering insight into the optimization of prestressed composite lining structures for use in high-pressure tunnel environments.</p>

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Effect of Interface Characteristics on Load Transfer and Deformation in Composite Tunnel Linings

  • 期刊论文

  • 发表日期：

    2025年8月21日

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  • Xinwei Tang,
  • Ziheng Wan,
  • Danqing Song,
  • Yue Wu

摘要

Prestressed composite linings are increasingly adopted in large-diameter tunnels subjected to high internal pressures and complex geological conditions due to their superior structural performance and long-term durability. This work presents a finite element model based on the stratum–structure method to systematically evaluate the influence of interface treatment methods—namely, cushion layers and reinforcing bars—on internal pressure distribution and joint load-bearing behavior. The analysis also considers the effects of surrounding rock weathering and backfill stiffness on the interaction between the lining and the surrounding rock. The results show that the laying area of cushion layers has a negligible effect on pressure distribution, whereas higher stiffness significantly facilitates earlier contact between the inner and outer linings, enabling joint bearing at lower internal pressures and reducing the load on the inner lining. For reinforcing bars, the layout range and density substantially affect the pressure contribution mechanism, while bar diameter has a limited impact. A greater installation angle accelerates the transition from separate to joint bearing. Higher surrounding rock strength leads to a greater internal pressure contribution from the rock, resulting in a more favorable load path, particularly in later loading stages. The influence of backfill stiffness is stage-dependent: from 0 to 1.6 MPa, increased stiffness enhances initial rock support; from 1.6 to 2.3 MPa, it significantly improves joint action; beyond 2.3 MPa, a stiffer backfill helps suppress stress concentration in the lining, reduces cracking risk, and maintains a higher load share for the rock. These findings provide engineering insight into the optimization of prestressed composite lining structures for use in high-pressure tunnel environments.