Aiming at the blasting effect of cutting hole in upward blind shaft, the compensation coefficient method is used to calculate the spacing of surrounding large empty holes and formulate the scheme. Smoothed particle hydrodynamics method (SPH particle method) is used for numerical simulation. The effect of surrounding empty holes and compensation coefficient on the blasting cavity and rock damage range are studied. The results show that when the hole spacing is constant, the explosion cavity area increases with the increase of compensation coefficient. When the compensation coefficient reaches 2.42, the blasting effect is the best and reaches the peak 0.54 m~2; Then the blasting effect reaches the limit, and the change of blasting cavity area tends to be stable. The rock damage range is limited due to the effect of explosives, and the overall change range is within 10%. The SPH particles in the simulation process can well simulate the rock movement state, empty hole filling and rock damage range in the blasting process. The simulation results are highly consistent with the cross-sectional area of the blasting cavity in the field test, indicating that the numerical simulation calculation has certain accuracy.

Smooth blasting is a commonly used blasting technique for the excavation of ultra-long mountain tunnels. This paper takes the construction of the Dongge section tunnel in Shenzhen City as the engineering background. It investigates the effect of relevant blasting parameters on the smooth blasting effect. Numerical models with different linear charge densities were established. Through analysis of the numerical simulation results, the optimal linear charge density suitable for this blasting project was determined. The results indicate that: The length of the main cracks in the smooth blasting layer on both sides of the blast holes and in the surrounding rock mass increases with the increase of linear charge density. At a linear charge density of 0.08 kg/m, the effect of crack penetration along the blast hole alignment is not good, with partial under-excavation observed. When the linear charge density is 0.12 kg/m, the crack length during the blasting process is the longest, resulting in greater damage to the surrounding rock mass. Through multiple analyses and calculations using numerical simulation, it was determined that a linear charge density of 0.10 kg/m yields better blasting effects. The outline of the smooth blasting is neater, and the half-hole rate is higher. Theoretical derivation and calculation results can provide reference for similar engineering projects.