Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

Table 3

Maximum PPV of each key control protected object using 6 types of blasting excavation method in I phase underground powerhouse.

Scheme	Charge (kg)	Generator layer (cm/s)	Turbine layers (cm/s)	New pouring concrete (cm/s)
Draw cut of deep hole	24.0	0.92	0.68	2.57
Draw cut of shallow hole	10.8	0.44	0.43	1.71
Presplitting blasting of deep hole	12.0	0.22	0.18	0.75
Presplitting blasting of shallow hole	7.3	0.16	0.13	0.60
Draw cut blasting with presplitting gap	24.0	0.89	0.63	2.43
Draw cut with damping ditch	24.0	0.31	0.21	0.83