Abstract: During the construction of Tianchangling Tunnel, the blasting induced vibrations were monitored to ensure the safety of an adjacent existing tunnel. The primary vibration frequency and duration were evaluated. The optimum explosive dosage was determined throughout the onsite blasting data processing so that the vibration at the existing tunnel met the code requirement. For the millisecond delayed blasting method, the relationship of the blasting vibration velocity fitted with the total explosive dosage found to meet the requirements of this project. Due to the complexity of the geological conditions and the length of the tunnel construction, the range of primary vibration frequencies of the blasting induced vibration are very wide. Under the same rock mass classifications, the peak vibration velocity at the toe of the existing tunnel with various distance to the center of blasting is evaluated for the safety of the existing tunnel.

Key words: Blasting Induced Vibration, Tunnel, Vibration Velocity, Primary Vibration Frequency