Fill in (1) holes then (2) holes after delaying (Refer to Figures 1, 2, and 3)) This can be applied for controlling of a crack direction (See Bellow).
Figure 1: Splitting of Large Boulder
|
d |
32-35 mm |
44-51 mm |
|
1 1/4-1 3/8 |
1 3/4-2 |
|
L |
30-40 cm |
60-90 cm |
|
1’-1’4 |
2’-3’ |
|
D |
70% of Height |
Figure 2: Trenching and tunneling of Rock
|
d |
38-51 mm |
|
1 1/2-2 |
|
L |
30-60 cm |
|
1’-2’ |
|
D |
1-1.8 m |
|
3’-6’ |
|
|
45°-60° |
| Reliever holes are necessary when trench is deep |
 |
Figure 3: Mass Concrete
|
|
Concrete |
reinforced Concrete |
|
d |
38-51 mm |
38-44 mm |
|
1 1/2-2 |
1 1/2-1 3/4 |
|
L |
50-90 cm |
40-60 cm |
|
1’8-3’ |
1’4-2’ |  |
WHAT IS STAFFII