Numerical analysis of the blasting excavation of tunnels with soil-rock interfaces

The effect of blasting vibration on Heishan tunnel with soil-rock interfaces was numerically analyzed with FLAC^3D when the tunnel was excavated by blasting excavation.In the analysis the blasting excavation was simulated by a method of spherical blast waves.According to the numerical result,the safe charge of explosives was proposed and its application was analyzed in the blasting control.It is indicated that that the stress is redistributed at the vault and the bottoms of the arch waist.Soil zones in the vault are sensitive to blasting vibration.Although plastic failure develops mainly in the vault of the tunnel and there are also some damages in the center soil connecting with rock,they do not affect the overall stability of the tunnel.