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| |
General
Concept Boulder |
|
|
|
| (1)Soft
Rock (Tensile Strength: < 60kg/cm2 : 85psi) |
(2)Middle
Hard Rock (Tensile Strength: 60-100kg/cm2 : 80-140psi) |
(3)
Hard Rock (Tensile Strength: > 100kg/cm2 : 140psi) |
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|
|
|
|
d |
38-44mm |
| 1
1/2"-1 3/4" |
D |
70%
of Height |
|
|
| |
|
|
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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 |
|
|
|
| |
Slabbing |
d |
32-35 mm |
44-51
mm |
1
1/4"-1 3/8"
|
1
3/4-2" |
L |
20-30 cm |
40-50
cm |
| 8"-1'
|
1'4"-1'8"
|
D |
90%
of Height |
|
|
|
| |
Underground
Excavation |
d |
38-44 mm |
| 1
1/2"-1 3/4" |
L |
30-60 cm |
| 1'-2' |
D |
Shown
in Figure |
|
|
| |
|
d |
38-51 mm |
| 1
1/2"-2' |
L |
60-90
cm |
|
2'-3' |
D |
90%
of Height |
|
|
|
| |
Leakage
of virgin rock |
| The
toe should be drilled at closer hole spacing and succussively broken
from the front row. No drilling will cause poor breakage. |
| d |
44-51
mm |
| 1
3/4-2" |
L1 |
30-40
cm |
| 1'-1'4"
|
L2 |
60-90
cm |
| 2'-3'
|
D |
Add
5% of Height |
|
80°-90°
|
|
|
| The
front holes (up to the sixth row) may be simultanious filled in. It
is more effective fr the removal to fill in 1 holes and then each
two rows (2,3) after a delay of 6-20 hours. |
|
| |
Trenching
Tunneling |
| |
Reliever
holes are necessary when trench is deep |
| d |
38-51
mm |
| 1 1/2"-2" |
| L |
30-60 cm |
| 1'-2' |
| D |
1-1.8 m |
| 3'-6' |
|
|
45°-60°
|
|
|
| |
Repeat
the same procedure for deeper case |
| |
|
| d |
38-51
mm |
| 1 1/2"-2'
|
| L1 |
40-60 cm |
| 1'4"-2' |
| L2 |
30-40 cm |
| 1'-1'4" |
| D
|
1-1.8 m |
| 3'-6' |
|
|
| |
|
| d |
38-44
mm |
| 1
1/2"-1 3/4" |
L |
30-60
cm |
| 1'-2'
|
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