Abstract: Damage should be controlled in order to ensure the safety of bedrock under blasting excavation in nuclear power plant. For this case, blasting vibration, sonic wave test and numerical simulation are employed to study the wave attenuation in rock mass and blasting induced damage under blasting excavation at Ling’ao Nuclear Power Station (LNPS) in Guangdong Province of China. The relationship between damage characteristic and peak particle velocity (PPV) at a certain distance from the charge are suggested. The method and the vibration safety threshold to control the damage depth for bedrock under blasting excavation are then presented. It is reported that when the PPV at 30 m from charge is not beyond the safety threshold of 5 cm/s, the damage depth of the bedrock will not exceed 2 m. The method and the safety threshold presented can ensure the safety of bedrock under blasting excavation in the project.

Key words: safety threshold, blast vibration, damage, rock mass, nuclear power station