Study on the Rationality of Tunnel Plane Strain Model Based on Stress Release Principle

Based on the finite element difference software FLAC3D, a three-dimensional refined simulation model for tunnel excavation and a plane strain model based on the stress release principle were established. By comparing the deformation characteristics of surrounding rock and the stress distribution of support structures, it is concluded that, apart from slight differences in the stress distribution of the steel arch, the results of the plane strain model and the three-dimensional refined model show high consistency in the deformation characteristics of surrounding rock and the stress distribution of anchor bolts. The calculated results for the maximum load on a single anchor bolt differ by 13.25%, and the differences in surrounding rock deformation and the maximum load on the steel arch are both less than 8%. The plane strain model based on the stress release method can well match the three-dimensional refined model, indicating its feasibility for practical engineering analysis.