Abstract

In order to prevent and control the large deformation of surrounding rock of tunnels, the selection of section type and the determination of excavation method were numerically investigated by using the self-developed code—Realistic Failure Process Analysis (RFPA^2D) and taking a specific project as the engineering background—Ruyi tunnel. Then, special measures were employed to deal with the dangerous parts of the section of the tunnel. Finally, the control effect of surrounding rock deformation was checked with displacement monitoring and microseismic monitoring. The results showed that the horseshoe-shaped tunnels with six centers and the bench excavation can prevent the occurrence of large deformation. The “support resistant limiting damper-H230 grid steel frame” and the increased depth of the inverted arch can effectively control the deformation of the vault and the arch bottom. Besides, it was revealed that the propagation and connection of cracks at the top of the tunnel are the most critical cause for the instability failure of the tunnel. Engineering application indicated that the selected section type, excavation method and special support measures for dangerous parts greatly reduce the deformation of surrounding rock and effectively solve the problem of large deformation of the weak broken surrounding rock.

摘要

为防治隧道围岩大变形，采用自主开发的程序——Realistic Failure Process Analysis（RFPA ^{2D ），对断面类型选择和开挖方法确定进行数值研究})，并以具体工程为工程背景——如意隧道。然后，对隧道段的危险部位采取了特殊措施。最后通过位移监测和微震监测验证了围岩变形的控制效果。结果表明，六心马蹄形隧道和台阶开挖可以防止大变形的发生。“抗支撑限位阻尼器-H230网格钢架”和增加的倒拱深度可以有效控制拱顶和拱底的变形。此外，揭示了隧道顶部裂缝的扩展和连接是隧道失稳破坏的最关键原因。