Table 3 Specific charge for tunnel blasting.

From: Cumulative damage characteristics of tunnel initial support concrete under blasting load

Type of blasthole

Detonator level

Delay time/ms

Number of blast holes

Charge quantity for a single blast hole/ kg

Single stage charge/ kg

Cutting hole

MS1

25~45

16

2.7

43.2

Auxiliary hole

MS3

55~85

12

1.5

18

Auxiliary hole

MS5

75~105

8

2.1

16.8

Auxiliary hole

MS7

85~115

11

1.2

13.2

Auxiliary hole

MS9

90~125

21

1.2

25.2

Auxiliary hole

MS11

95~130

11

1.2

13.2

Peripheral hole

MS13

100~140

25

0.6

15

Floor hole

MS15

100~150

4

1.2

4.8

Subtotal

  

108

 

149.4

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