三点加载下高性能纤维混凝土顶管承载特性及配筋方案研究

Load-bearing Behavior and Reinforcement Schemes of High-performance Fiber-reinforced Concrete Jacking Pipes under Three-point Loading

  • 摘要: 高性能纤维混凝土(HPFRC)因其优异的强度、延性和耐久性,在电力顶管工程中具有应用潜力,但目前关于HPFRC顶管力学性能的研究较为匮乏。采用模型试验、解析计算和数值模拟方法,对强度等级为C150的HPFRC顶管在三点加载条件下的承载特性及不同配筋方案对结构受力响应的影响进行研究。结果表明:HPFRC顶管的荷载-位移初期呈线弹性关系,荷载超过200 kN/m后,位移增速加快、管节出现裂缝,荷载达到437 kN/m时结构破坏;与常规混凝土顶管相比,HPFRC顶管的承载能力和抗裂性能显著提高,钢筋用量和壁厚降低,且损伤后仍能保持较强承载力;3种分析方法所得的顶管结构受力及破坏过程基本一致,但解析计算方法在裂缝宽度预测上存在较大误差;不同配筋方案对结构损伤和承载能力的影响显著,双侧配筋和内侧配筋方案表现出更优的抗损伤能力。

     

    Abstract: High-performance fiber-reinforced concrete (HPFRC) exhibits significant potential for use in electricpower pipe-jacking engineering due to its superior strength, ductility, and durability. However, research on the mechanical properties of HPFRC jacking pipes remains scarce. This study investigates the load-bearing characteristics of C150 HPFRC jacking pipes under three-point loading and evaluates the influence of different reinforcement schemes through model tests, analytical calculations, and numerical simulations. The results indicate that the loaddisplacement relationship of HPFRC jacking pipes initially follows a linear elastic trend. When the load exceeds200 kN/m, the displacement accelerates, and cracks develop in the pipe segment. Structural failure occurs at a peak load of 437 kN/m. Compared to conventional concrete jacking pipes, HPFRC pipes demonstrate significantly improved load-bearing capacity, crack resistance, and post-damage residual strength while requiring less steel reinforcement and reduced wall thickness. The three analytical methods yield consistent results regarding structural stress behavior and failure progression. However, the analytical calculation method exhibits notable errors in predicting crack widths. Furthermore, different reinforcement schemes significantly influence structural damage and load capacity, with double-sided and inner-layer reinforcement configurations demonstrating superior damage resistance.

     

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