<p>To control the asymmetric failure of tunnel surrounding rock and lining structure caused by anisotropy of layered soft rock, a study was conducted on the directional support effect of rock bolt under varying large deformation grades in three typical layered soft rock tunnel sections of the Jiuzhaigou-Mianyang Expressway. Initially, based on statistical analysis of maximum deformation and strength–stress ratios in typical tunnels, the deformation grades of layered soft rock tunnel were categorized into slight, moderate, and severe grades. Subsequently, model tests with a 1/50 scale ratio were conducted to investigate the effect of rock bolt directional support on the asymmetric deformation and stress of surrounding rock and lining structures under different large-deformation grades. Furthermore, numerical simulations were employed to verify the accuracy and rationality of rock bolt directional support. Study found that the asymmetric failure of layered soft rock tunnel mainly occurs where the tunnel contour line intersects the bedding plane, due to the combined influence of geo-stress field distribution and the orientation of soft bedding. This asymmetric characteristic phenomenon becomes more apparent as the large-deformation grade increases. Nevertheless, rock bolt directional support can effectively mitigate asymmetric failure in layered soft rock tunnels and enhance control over the anisotropic behavior of the surrounding rock.</p>