Weak structural plane deformation is responsible for the non-uniform large deformation disasters in layered rock tunnels, resulting in steel arch distortion and secondary lining cracking. In this study, a servo biaxial testing system was employed to conduct physical modeling tests on layered rock tunnels with bedding planes of varying dip angles. The influence of structural anisotropy in layered rocks on the micro displacement and strain field of surrounding rocks was analyzed using digital image correlation (DIC) technology. The spatiotemporal evolution of non-uniform deformation of surrounding rocks was investigated, and numerical simulation was performed to verify the experimental results. The findings indicate that the displacement and strain field of the surrounding layered rocks are all maximized at the horizontal bedding planes and decrease linearly with the increasing dip angle. The failure of the layered surrounding rock with different dip angles occurs and extends along the bedding planes. Compressive strain failure occurs after excavation under high horizontal stress. This study provides significant theoretical support for the analysis, prediction, and control of non-uniform deformation of tunnel surrounding rocks.

Download PDF:

Keywords: Bedding plane, Three-dimensional (3D) printing, Physical model test, Non-uniform deformation, Digital imaging correlation (DIC)