Geoscience Reference
In-Depth Information
sectional area of the structure divided by the calculated filled cross-sectional area of
the geotextile container (see Figure 6.4).
During the drop a geotextile container has to be able to deform in order to slide
through the bottom opening of the split barge. For the same volume of fill material
the greater the circumference, the more the geotextile container can deform. The
requisite circumference of the geotextile container is as follows:
⎛
⎜
⎞
A
b
(6.2)
S
25
b
≥⋅
⎛
⎝
+
0
0
where:
S
=
circumference of the cross-section of the geotextile container [m];
0
=
width of the opening of the split barge [m];
A
=
filled cross-sectional area of the geotextile container in the barge or cross-
section of the barge [m
2
].
25%. The deviation is
due to the factor of 2.5 in Equation 6.2 not being known precisely. In the case of a
split barge with relatively high friction during release, the factor of 2.5 should be
replaced with a factor of 3 [22]. This will result in a flatter and lower geotextile
container after dropping.
In Figure 6.5 the minimum required circumference of a geotextile container (filled
with sand) is given for various opening widths of the split barge (
b
0
) as a function of
the filled cross-sectional area.
For a split barge, suitable for dropping geotextile containers, a rule of thumb is
that the bin width is equal to 1/5 of the bin length. In addition, the opening width of
the split barge should be at least 50% of the bin width.
The accuracy for determining
S
lies in the order of
±
cross-section of structure
cross-section of geotextile container
Number of required geotextile containers =
Figure 6.4
Estimation of the required number of geotextile containers in a structure.
