Abstract: The tunnels in Da Maoshan have large cross\|sections and the clear\|spacing between two tunnels is small. The techniques of controlling blasting in the new tunnel construction while maintaining the stability and safety of the existing adjacent operating tunnels are studied in this paper. The vibrations induced by blasting during the new tunnel construction are monitored. The measured results are compared with the values from numerical simulations and theoretical analyses. The monitoring results indicate that the blasting design parameters can be optimized when the new tunnel construction is close to an existing one. This case study provides a theoretical approach as well as practical experience in safeguarding the existing operating tunnels while blasting in the adjacent new tunnels.   

Key words: tunnel engineering, small clear\, spacing tunnel group, blasting monitoring, blasting parameter optimization