Analysis of surface vibration effect on tunnel excavation section induced by tunneling blasting

In view of the shortage of theories on the surface vibration effect in the excavated section of the tunnel, the surface vibration effect of the tunnel is analyzed based on theoretical and field measured data. Firstly, the blasting model for a tunnel is simplified, and the blasting of cut holes is simplified to a series of spherical charge blasting. Then the surface vibration in the excavated section of the tunnel is transformed into the surface vibration of spherical charge by conformal mapping. Finally, the method for calculating the vibration velocity of surface particles in the excavated section is obtained. Through practical projects, The feasibility of the theoretical method is verified by comparing the theoretical and measured peak velocity distribution curves. The distribution laws of the tunnel depth on the peak velocity of the tunnel axis are discussed by using the theoretical method. It is found that when the tunnel depth is shallow, the peak velocity of the excavated section larger than that of the unexcavated section is obvious. With the increase of the depth, the phenomenon gradually disappears.