不同开挖工法对相山隧道围岩稳定性影响研究

Study on the Influence of Different Excavation Methods on the Stability of Surrounding Rock in Xiangshan Tunnel

摘要: 本文针对地质条件复杂的相山隧道，采用三维有限元数值模拟方法，系统研究了全断面法、台阶法及CD法三种常用开挖工法对围岩应力分布、支护结构受力及围岩稳定性的影响。研究结果表明：不同工法下围岩主应力分布均呈对称形态，对称轴为隧道中心线，拱腰与拱脚区域为应力集中关键部位；CD法在控制拱顶与拱腰围岩应力方面效果显著，全断面法则在拱脚处应力集中程度较低；支护结构分析显示，断层区域应力响应强烈，全断面法在断层处应力增幅最大(拱顶53.27%，拱底30.67%)，CD法表现最优。研究结论可为类似地质条件下隧道开挖工法选择、支护设计与施工控制提供理论依据与工程参考。

Abstract: This paper focuses on Xiangshan Tunnel, which is characterized by complex geological conditions. Using three-dimensional finite element numerical simulation, the study systematically investigates the effects of three common excavation methods—full-face method, bench-cut method, and CD method—on the stress distribution of surrounding rock, the mechanical response of the supporting structure, and the stability of the surrounding rock. The results indicate that under different excavation methods, the principal stress distribution in the surrounding rock exhibits a symmetrical pattern, with the tunnel centerline as the axis of symmetry. The haunch and arch foot regions are identified as key areas of stress concentration. The CD method proves particularly effective in controlling stress at the vault and haunch, while the full-face method results in relatively lower stress concentration at the arch foot. Analysis of the supporting structure reveals a strong stress response in fault zones, with the full-face method showing the highest stress increase in these areas (53.27% at the vault and 30.67% at the invert), whereas the CD method performs the best overall. The findings of this study provide a theoretical basis and practical reference for the selection of excavation methods, the design of support structures, and construction control in tunnels under similar geological conditions.