Geoscience Reference
In-Depth Information
8
7
6
5
4
saturated
unsaturated
3
2
1
0
0
5
10
15
20
fall height (m)
Figure 6.9
Fall velocity as a function of the fall height (
=
the water depth minus the draught of the
split barge) for a container with a volume of 260 m
3
, saturated fill (
ρ
=
1800 kg/m
3
) and
unsaturated fill (
ρ
=
1460 kg/m
3
).
the water depth for a container with
V
=
260 m
3
and for the cases of saturated fill
(
72 m
2
.
For this example, both cases show that terminal velocity still has not been reached at
20 m water depth.
ρ
=
1800 kg/m
3
) and unsaturated fill (
ρ
=
1460 kg/m
3
), for
C
d
=
1 and
A
s
=
6.5.4 Required tensile strength
Using the analysis presented above, the required tensile strength of the geotextile con-
tainer can be determined.
If it is assumed that
E
fill
is fully mobilised even at small strain in the geotex-
tile, then the energy absorbed by the geotextile (
E
g
) is equal to the fall energy minus
the energy absorbed by the fill material:
(6.10)
EEE
geo
EE
−
E
al
f
l
l
l
E
ill
f
From
E
geo
the strain in the geotextile (
ε
g
) during impact can be calculated as [22, 17]:
E
SJ
(6.11)
geo
=⋅
2
ε
g
Thus, producing a geotextile tensile load of:
(6.12)
TJ
g
′
⋅
ε
TJ
T
g
