Study on Energy Release of Surrounding Rock under the Multiple Unloading Disturbance during Tunnel Excavation

Table 1

Blasting design parameters of 2# underground laboratory.

Hole type	Charge weight	Quantity	Hole count	Delay
Cut hole	0.2	12	8	ms1
Breaking hole	0.2	19	20	ms3
	0.2	17	17	ms5
	0.2	35	19	ms7
	0.2	29	23	ms9
Periphery hole	0.2	23	50	ms11