Research on optimization of parameters for excavation and smooth blasting boreholes in mountain tunnels

To improve the uneven distribution of fractured rock blocks in the Aktep Tunnel in Xinjiang, the key parameters of the existing blasting plan, such as the inclination angle of the cutting hole and the spacing between surrounding holes, were optimized and analyzed through theoretical calculations using ANSYS/LSDYNA numerical simulation method; Four sets of models for cutting and smooth blasting were constructed separately, and the contour of the blasting chamber after blasting was obtained through simulation, based on which the blasting effect was analyzed. The results showed that compared with the blasting effects when the excavation angles were 70°, 75°, and 80°, when the excavation angle was 75°, while ensuring the excavation depth, the damage to the surrounding rock mass caused by blasting could be reduced, the blasting of the rock mass was more uniform, and the rock block rate was significantly reduced; Comparing the blasting effects of peripheral holes with a spacing of 50, 60, and 70 cm, as the spacing between holes increases, the damage zone between the two holes changes from through to non through. The best blasting effect can be achieved when the spacing between peripheral holes is 50 cm. The optimized blasting plan was applied to practical engineering, and the blasting effect was significantly improved, greatly enhancing construction efficiency.