Effect of Tunnel Blasting Operation on the Surface Penstock Pipe

Abstract

This paper presents the investigation of the effect of ground vibration components induced blasting events in Ordu-Mesudiye Highway Topçam tunnel on the penstock pipe (PP) having 35-400 slopping of Topçam Hydro-Electrical Power Plant (HEPP). Until the tunnel excavation passed under the PP of HEPP, a total of 37 shots (26 upper halves and 11 lower half) were monitored and the ground vibration components (peak particle velocity, acceleration, displacement and frequency) were measured in two different stations. It was also examined whether the concrete platform under this PP had a crack, damage or etc. As a result of these workings, a maximum of 220 kg total charge was used and the charge weight per delay varied between 1.0-18 kg in the shots. The distance of shots to measurement station was between 78.04 and 170.16 m. 6 PPVs, 11 accelerations and a displacement value exceeded the threshold values determined. However, the vibration values were taken under control with changing the blasting parameters and it was provided that the tunnel excavation passed under the PP of Topçam HEPP.