Abstract: To investigate the influence of joints in horizontally stratified soft rock formations on the propagation and attenuation characteristics of blast-induced stress waves, this study employs LS-DYNA numerical simulations based on the Changzheng Tunnel on the Chengdu-Zigong high-speed railway. The research systematically analyzes the propagation patterns, vibration attenuation, and energy dissipation characteristics of stress waves in jointed rock masses under varying joint thicknesses and spacings, elucidating the impact of joint geometric characteristics on vibration attenuation zoning. Field monitoring data further validate the reliability of the numerical approach. Key findings reveal that joint thickness and spacing significantly govern stress wave energy dissipation and attenuation. When the joint thickness exceeds 0.4 times the charge radius, the amplitude of vibration velocity attenuation stabilizes. Increased joint thickness enhances stress wave reflection energy while markedly reducing transmitted energy,with both trends reaching equilibrium beyond critical thresholds. Under multi-joint conditions, the peak resultant vibration velocity decreases with larger joint spacings, exhibiting predictable decay rates. Based on vibration attenuation zoning, a new classification standard for blast control in jointed rock masses is proposed. Field-measured surface particle vibration velocities demonstrate strong agreement with numerical results.