Research on the effect of bedding dip angle on deformation and failure of thin layered surrounding rock based on 3D-printed physical model tests

Layered rocks are frequently encountered in underground engineering construction. Due to their significant bedding structure, their failure mechanisms are complex. Current research on the failure mechanisms of layered rocks mainly relies on rock mechanics tests. However, this method has problems such as difficult sampling, large discreteness, and small scale. Therefore, we propose a 3D printing physical model test method for layered rocks. This method can conveniently and accurately produce model specimens with different bedding angles, and has the advantages of low- test cost, short cycle, more intuitiveness, and controllable conditions. Based on this method and supplemented by acoustic emission and digital speckle techniques, we studied the deformation and failure mechanisms of tunnel models with bedding dips of 0°, 30°, 60°, and 90° under the dominance of horizontal stress. The results show that the normal deformation of the bedding is particularly prominent, leading to obvious asymmetric deformation and failure characteristics of the tunnel model, indicating that the bedding structure plays a dominant role in the stress transfer and deformation evolution process of the tunnel.