Geoscience Reference
In-Depth Information
Figure 6.3
Relationship between degree of filling, filled cross-sectional area and circumference of
geotextile containers. For example, a geotextile container with a cross-sectional area of
10 m
2
with a degree of filling of 40% (
f
=
0.4) will have a circumference of about 18 m.
6.3 GEOMETRIC DESIGN
In Figure 2.1 a general design chart is given for geotextile-encapsulated sand elements.
The first step in the design process is to establish the functional and technical require-
ments. This is an area that falls outside the scope of this manual. As already indicated
in Section 2.2, it is assumed that the designer is already at the design process stage
and has a clear view of the functional requirements, has a draft design of the entire
structure and wants to elaborate on it.
First, the main dimensions of the structure are established. Then, the size of the
elements and the construction of the structure based on experimental data, construc-
tion feasibility, economic feasibility and application area are carried out. Where pos-
sible, this is done in consultation with the contractor.
In [14, in Dutch] indicative values are given for the ultimate dimensions of geotex-
tile containers after placement in relation to the size of the split barge. Table 6.1 shows
a revised version of this table based on a degree of filling of around 40% of the maxi-
mum possible cross-sectional area and of around 80% of the bin volume of the split
barge used in placement. The shaded part gives an indication of common split barge
dimensions.
The filled cross-sectional area (
A
) of the geotextile container can be calculated by
multiplying the width (
b
) by the height (
h
) of the geotextile container (
b
h
), but that
will overestimate the filled cross-sectional area because the shape is not rectangular.
A more accurate way of determining
A
is to divide the volume (
V
) of the container by
the length (
l
) of the barge bin (
V/l
).
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