Abstract: Improper handling of the demolition blasting of hydraulic trestle pier will cause permanent effect on the hydraulic structure. Based on monitoring data and macroscopic survey, the authors analyzed the toppling duration and vibration effect of the trestle of Shimenkan hydropower station, and gave the calculation formula of toppling duration which is an improvement compared with former methods. Measures of reducing vibration effect were proposed. No adverse impact was exerted on surrounding buildings by the blasting, and the monitored toppling duration data generally agreed  with theoretical calculation result.

Key words: blasting, trestle, duration, vibration, toppling