Study on Optimization of Initial Support for a Tunnel in the Fracture Zone Based on the Strength Reduction Method

Abstract

In this paper, the fracture zone of the Chunxuan Road Tunnel in Jinan, Shandong Province, China was selected for the engineering background. With reference to the field monitoring data, a finite element model was established based on the strength reduction method. With the aid of this model, the influences of different initial support parameters (including lining, bolt and steel arch) on the tunnel deformation in the fracture zone were analyzed to obtain reasonable initial support parameters. The results show that the tunnel deformation under the original initial support is severe. Among the initial support methods, such as lining, bolt, and steel arch, the parameters of the lining and steel arch significantly influence the tunnel deformation in the fracture zone. Therefore, selecting appropriate initial support parameters can effectively control the tunnel deformation in the fracture zone. After the optimized support scheme is adopted, failure instability no longer occurs in the tunnel and the tunnel deformation is also effectively controlled. The research findings provide a clear reference for deformation control and support scheme optimization of similar projects.