Abstract: The cut angle is a critical design parameter for tunnel blasting in bedded slate. Failure to consider the bedding dip effect when designing the cut angle may adversely affect blasting performance or even lead to cut blasting failure. To investigate the optimal cut angle design for slate tunnel blasting under different bedding dip conditions,this study conducted static and dynamic tests on slate with varying bedding dip angles in the Bayueshan Tunnel to determine the Holmquist-Johnson-Cook (HJC) constitutive model parameters. Using ANSYS / LS-DYNA,nine numerical models of cut blasting for slate tunnels were developed under different bedding dip and cut angle conditions. These models simulated the effective stress and damage evolution characteristics of the surrounding rock,enabling determination of the optimal cut angle design. Field blasting tests based on the optimal cut angle design were then conducted in the Bayueshan Tunnel for validation. The results show that under bedding dip angles of 0°,60°,and 90°,the optimal cut angles are 80°,70°,and 60°,respectively,yielding the highest peak effective stress and largest blasting-induced damage area for optimal cut blasting performance. Five field tests confirmed these findings, demonstrating an 11. 15% increase in average advance per cycle,a 10. 98% improvement in blast hole utilization rate,a 7. 8 m reduction in the farthest muck-throwing distance,and effective prevention of the " belly bulging" phenomenon. The findings provide a valuable reference for cut blasting parameter design in bedded slate tunnels.