Numerical Study on the Mechanism and Application of Artificial Free Surfaces in Bedrock Blasting of Shield Tunnels

Table 10

Peak values of the particle vibration velocity in the direction.

Free face	Particle no.	Distance from the center of the hole (cm)	Peak vibration velocity of a particle in the direction (cm/s)
			Group A	Group B	Group C	Group D	Group E
With	1	40	1.31	1.16	0.82	0.51	0.32
	2	80	0.65	0.57	0.41	0.26	0.21
	3	130	1.27	1.13	0.81	0.54	0.38
	4	180	1.13	1.01	0.76	0.59	0.46
	5	230	0.86	0.78	0.58	0.5	0.41
	6	280	0.73	0.65	0.47	0.39	0.37
Without	1	40	2.96	2.84	2.48	1.79	1.11
	2	80	2.85	2.73	2.34	1.65	1.03
	3	130	2.76	2.64	2.21	1.55	0.99
	4	180	2.64	2.51	2.05	1.44	0.95
	5	230	2.45	2.31	1.86	1.35	0.94
	6	280	2.2	2.06	1.69	1.27	0.93