Environmental Engineering Reference
In-Depth Information
Fig. 2.24 The effective mass of packed explosives with side scattering/
fl
ying [
18
]
If the packed height of explosives is h, the effect height
fl
flying to the right end
ha = 4h/9.
(2) The effective mass of packed explosives with side scattering/
ying
The most common conditions are that the detonation starts from one end, the
products
fl
fly/scatter in any direction (Fig.
2.24
).
In Fig.
2.24
, cylinder 101 is the effective mass of packed explosives with
fl
fl
ying
to the bottom. Its height is ha and radius is r.
Determination of ha is based on the assumption that the time of expansion waves
transportation to the packed center equals that of detonation waves passing ha.So
s
¼ r
=
c ¼ ha
=
D
:
The velocity of side expansion waves is approximate c
D
=
2
:
And r
=
D
=
ð
2
Þ
¼
ha
=
D
;
The height of effect packed explosives equals its diameter. The
volume of effective packed explosives is 1
so ha ¼
2r
:
32r
p
r
2
p
r
3
=
ð
Þ
¼
2
=
3
:
The mass of effective packed explosives is Eq.
2.58
.
r
3
Ma ¼
2
=
3
p
q
0
ð
2
:
58
Þ
¼
p
r
2
and
2.58
into Eq.
2.54
, then
Substitute S
3
p
r
3
8
27
mD
S
¼
8
27
2
16
81
r
q
0
D
i ¼
p
r
2
q
0
D ¼
ð
2
:
59
Þ
When the packing of explosives is long enough and detonation starts from one
end, the speci
16
81
r
q
0
D.
(3) The effective height of packed explosives
When the height of packed explosives is not long enough, the effective packed
explosives
c impulse of the bottom is i ¼
fl
flying to the base are not guaranteed to be cone. When the effect height
3r
;
h ¼
according to the theory of two ends
fl
flying/scattering, the packed height to
the bottom is 4
3r. This height is shorter than effect height 2r,
which is the theoretical value (Fig.
2.25
).
Figure
2.25
describes that the measurement of brisance without enough packing
height does not need to take the packed mass into consideration. But the effective
packed height should meet 4
=
9h ¼
4
=
93
ðÞ
¼
4
=
=
9h ¼
2r
:
