Analysis of blast-induced ground vibration under surface explosion

The blasting operation is vital in the construction of tunnels and channels or in mining when encountering hard geological environments to facilitate the progress of a project. The level and range of damage due to the blast are affected by the energy of shock waves generated after explosion. The control of seismic damage is a major issue in blasting engineering and cannot be neglected. The stratum layer or buildings on the earth’s surface can be damaged when blasting-induced vibration strength exceeds the allowed range. In order to reduce the degree of damage, the patterns of blasting vibration must be studied and controlled. Therefore, the propagation characteristics of shock waves on the earth’s surface are important factors to be studied before the planning and designing of a project. This paper adopted a mutual verification method between the blasting experiment and numerical analysis results for verifying the reliability of numerical simulation based on experimental data. The numerical analysis method analyzed the dynamic mechanical behavior of blasting vibration using the finite element method. The LS-DYNA program was used to simulate TNT explosive and surface contact blasting in semi-infinite space and in propagation of the resulting seismic waves. The propagation characteristics, represented by temporal and spatial changes of surface acceleration, were investigated. The analysis results showed that post-explosion dynamic characteristics of the earth’s surface simulated by finite element method yielded promising simulation results. In addition, the propagation characteristics of stress waves were observed from the dynamic mechanical behavior of surface acceleration after explosion. That is, the maximum main stress presented a pattern of progressive attenuation with increasing distance from the blasting source. The results are able to provide reference for the protection of engineering structures from blasting vibration damages.