Effect of lateral pressure on the stability of inclined layered rock tunnel: A 3D-printed model investigation by cement-based materials

The inclined layered rock tunnel engineering in the alpine canyon area subject to tectonic stress will be influenced by high lateral stress. Currently, there are scarce reports on the impact of the lateral pressure coefficient on the stability of inclined layered rock tunnels. Hence, the mechanical response of the inclined layered tunnel model was investigated based on the 3D-printed model test, supplemented by acoustic emission (AE) and digital image correlation (DIC) monitoring methods under three cases of lateral pressure coefficients of 1.2, 1.5 and 1.8. The results reveal that for the tunnel model with a 60° bedding inclination, the bearing capacity is negatively correlated with the lateral pressure coefficient. The normal deformation of the bedding of the tunnel model is prominent, exhibiting significant asymmetric deformation characteristics. When the lateral pressure coefficient k increases from 1.2 to 1.5, the failure of the tunnel model changes from shear-slip failure along the layer to bedding cracking and buckling failure of the sidewall. The test results have enlightenment significance for the stability evaluation of inclined layered surrounding rock tunnels in the alpine canyon area.