Face Stability and Reinforcement of the Tunnel in Weak Surrounding Rock

According to the influence of surrounding rock levels and buried depths on the face stability of the tunnel. A stability analysis model of the full-face tunnel with weak surrounding rock is established based on the finite element method (FEM) and the Drucker-Prager yield criterion. The results indicate that the plastic failure zone gradually expands with the increase of the buried depths, and the plastic failure zone was penetrated and expanded to the inside away from the tunnel face. When the buried depths reach a certain depth, the plastic failure zone of surrounding rock tends to be stable, and the relationship between the plastic failure depths of the tunnel face and the buried depth is established. The overlap of the Glass Fiber Reinforcement Anchor (GFRA) is a critical aspect for the stability of tunnel face. Therefore, a practical method of determining the overlap length of the glass fiber reinforcement anchor in the tunnel face is proposed. The Ma Weishan tunnel is used as the engineering background, the overlap length of the glass fiber anchor is determined under the conditions of the IV and V surrounding rock levels.