层状地层软岩隧道形变控制措施研究

软弱层状岩体具有自稳性较差，且强度各向异性等特点，隧道修建过程中常出现初支混凝土开裂、型钢拱架或格栅扭曲、支护侵限等大变形破坏现象。以国道318线折多山隧道工程为依托，通过开展有限差分数值模拟对层状地层软岩隧道大变形破坏特征进行了分析。研究结果表明:随着节理强度的增加，层状岩体的横观各向同性性质减弱，塑性区的分布从由节理面控制变为沿隧道轴线对称分布，且塑性区的范围也有所减小；从变形控制角度分析，对围岩整体进行注浆加固及增加支护结构的强度可以有效控制围岩变形，而仅对节理进行加固的效果较差。

Study on Deformation Control Measures of Soft Rock Tunnel in Layered Stratum

Soft and weak layered rock mass has the characteristics of poor self-stability and strength anisotropy, etc. The phenomenon of large deformation, such as cracks of primary supporting concrete, distortion of section steel or grid steel frame and beyond-limit deformation of support often occur in the process of tunnel construction. To solve this problem, Zheduoshan tunnel of national highway 318 line is taken as an example to carry out finite discrete element method (FDM) simulations. The results show that, with the increase of the joint strength, the transverse isotropic property of layered rock is weakened. The distribution of plastic zone is not controlled by the joint surface and is symmetrical along the tunnel axis. And the range of plastic zone is also decreased. From the point of view of deformation control, the deformation of the surrounding rock can be controlled effectively by grouting reinforcement and increasing the strength of the supporting structure and the effect of only joint reinforcement is poorer.