Environmental Engineering Reference
In-Depth Information
Fig. 2.47 Explosion of liquid
explosives in/under water
they scatter radially. So the water column projects out of water radially. The gas
bubbles have maximum compression when they reach the surface. And the
oa-
tation velocity of gas bubbles is much faster. Now all water above gas bubbles are
projected upward, and a high and narrow fountain column is generated. The height
and projection velocity of fountain columns are determined by the depth of
explosives. The explosion phenomena of liquid explosives are in Fig.
2.47
.
Because of the re
fl
ection of sparse waves from free surface, the damage of
explosion in water is obviously improved compared to that on ground. This
property can be used to improve the utilization rate of explosives. But if the
explosion occurs in deep enough water, the bubbles are dispersed or dissolved
before they reach the free surface. Now there is no fountain. For general explosives,
the depth is calculated by below equation.
fl
0
p
3
h
9
:
½
W
Here, h is the depth of explosives in water; and W is the mass of explosives
(2) Existence of water bottom
Like the explosion on the ground, explosion in water increases the pressure of
water shock waves. For rigid water bottom, it equals two times of explosion power.
In fact, the water bottom is not absolutely rigid, and it absorbs part of energy.
Experiments indicate that in the water bottom with sandy soils, shock wave pres-
sure increases up 16 % and impulse goes up 35 %.
In summary, the explosion of explosives in/under water generates water shock
waves, bubble impulse, and pressure waves. All of these can cause serious damage
for the targets.
