To improve the contour quality of smooth blasting in rock tunnels, a comprehensive study was conducted on the initiation behavior of emulsion explosives subjected to axial shaped-charge jet impact under different charging configurations, confinement conditions, and charge spacings through model experiments, numerical simulations, and field investigations. The results indicate that: (1) the axial shaped-charge charging structure significantly enhances the stability of jet-induced initiation, while stronger confinement conditions and shorter charge spacings further improve initiation reliability. Under surrounding-rock confinement, interval charging based on axial shaped-charge liners can achieve reliable detonation transfer between explosive segments; however, the charge spacing must be maintained within an appropriate range. (2) Charge spacing is the dominant factor controlling stable detonation transfer. As the spacing increased from 10 cm to 75 cm, the jet-tip pressure decreased from 3.84 GPa to 0.85 GPa, accompanied by an increase in the critical penetration depth required to establish stable detonation in the acceptor explosive. (3) A novel shaped-charge tube–liner charging structure integrating axial detonation transfer and radial directional rock fragmentation was developed. Compared with the conventional continuous charging structure, the maximum overbreak and underbreak were reduced from 33.7 cm to 9.6 cm, while the maximum damage depth of the surrounding rock decreased from 0.94 m to 0.65 m. These improvements effectively enhanced contour control and minimized blast-induced rock damage, thereby significantly improving the smooth-blasting performance of tunnel excavation. The proposed charging structure provides a promising approach for achieving precise contour control and damage reduction in underground rock engineering.