Blasting Vibration Law and Prediction in the Near-Field of Tunnel

Table 2

Suggested definitions of tunnel blast monitoring regions.

Distance region	Maximum expected PPA (g)	Scaled distance (m/kg^0.5)
Extreme near-field	>100	SD ≤ 0.5
Near-field	10–100	0.5 < SD ≤ 2.5
Intermediate-field	3–10	2.5 < SD ≤ 7.0
Far-field	<3	SD > 7.0

Note. PPA is short for peak particle acceleration.