Prediction of Bench Blasting Vibration on Slope and Safety Threshold of Blasting Vibration Velocity to Undercrossing Tunnel

Table 1

Blast hole parameters in bench blasting.

Classification	Hole spacing (m)	Hole row-spacing (m)	Minimum burden (m)	Stemming length (m)	Single hole charge (kg)
Presplitting hole	1.5	4	—	2.5	12–16.4
Main blast hole	4	3.6	3.6	2.5–4	75–108

Note. The type of explosive is emulsion explosive, the detonation velocity is 3500 m/s, the charge density is 1000 kg/m³, the equivalent charge diameter is 0.072∼0.084, the bench height is 12−15 m, the hole depth is 14−17 m, the borehole diameter is 115 mm, the specific consumption of the explosives is 0.3 kg/m³, the maximum charge per delay is 108−376 kg, and the total charge of each blasting is 0.94–4.8 t.