Stability Analysis of Underground Multicavities in Bench Blasting Vibration

Table 3

Critical vibration velocity of the wall rock of the grotto[5].

Compressive strength (MPa)		Tensile strength; (MPa)	No damage; (m/s)	Slight damage; (m/s)	Intermediate damage (m/s)	Serious damage; (m/s)
Hard rock	75–110	2.1–3.4	0.27	0.54	0.82	1.53
	110–180	3.4–5.1	0.31	0.62	0.96	1.78
	180–200	5.1–5.7	0.36	0.72	1.11	2.09
Soft rock	40–100	1.1–3.1	0.29	0.58	0.90	1.67
	100–160	3.4–4.5	0.35	0.70	1.07	1.99