Geoscience Reference
In-Depth Information
begins to move down through the opening. This process can continue until the critical
opening width is reached (
b
0
b
crit
). An estimation of the critical opening width (
b
crit
)
can be made by assuming that the geotextile container has a rectangular shape as it
exits the barge. Thus, the opening width necessary for the container to pass through
the barge opening is:
=
2
SS
16
A
⋅
S
−
(F.9)
b
=
crit
2
A
⋅
where:
S
=
circumference of the geotextile container (perpendicular to its axis) [m];
A
=
filled cross-sectional area of the geotextile container (perpendicular to its
axis) [m
2
].
A more accurate method to calculate the critical opening width is given in [17].
If the geotextile container remains suspended for a brief time in the bin just before
complete release from the split barge, the strength of the geotextile must be sufficient
to carry a major part of the submerged weight. The tensile load in the geotextile is
then nearly half of the submerged weight of the geotextile container per meter length.
Due to the fact that the total amount of sand will not be situated at the bottom of the
barge and thus not all sand will be in the lower part of the geotextile container, the
formula is written as follows:
(F.10)
T
′
A
045
γ
For example, if the container cross-sectional area is 10 m
2
and the buoyant unit
weight of the fill is 9 kN/m
3
, then the load in the geotextile will be 41 kN/m. If the
container remains suspended on one side of the bin for an additional brief period of
time the load will be uneven and thus the tensile loads in the geotextile locally can be
considerably greater.
