Dynamic response and control of middle rock sidewall under impact of blast loading

Abstract

This study focuses on the dynamic response and control of middle rock sidewall (MRS) during blasting. First, the spatial distribution characteristic of blasting vibration in MRS was investigated thoroughly based on the blasting of temporary ship lock and ship lift of the Three Gorges project. Results demonstrated that the distribution of peak particle velocity (PPV) in MRS is parabolic, and the vibration amplification could be found obviously at the free surface. Site experiments were designed to determine the damage threshold of PPV used in the vibration control of blasting excavation of MRS. Results indicated that the PPV threshold of MRS is stricter than that of the conventional condition due to its unique geometric shape. Then numerical simulation was implemented to reproduce the dynamic response in MRS under blasting by using the LS-DYNA commercial software. Results revealed that the PPV distribution obtained by numerical simulation match well with that of site experiments. The reflection and superposition processes of blasting stress wave were investigated and verified against the comparison between different kinds of stress waves. Finally, the most optimal width of MRS was determined to make the peaks and troughs of different stress wave occur at the same position according to the interference theory of stress wave. The results of numerical simulation and theoretical calculations were compared to verify the rationality of the optimal width determination.