Geoscience Reference
In-Depth Information
Dimensions and shape
of geotextile tubes
When a geotextile tube is empty and lying flat on the ground surface, its width is
equal to half its circumference. When fully filled (degree of filling
=
1.0), it has a
circular shape with a radius
R
). In practice, a degree of filling
of between 0.60 and 0.85 can only be achieved. At this degree of filling a shape
is obtained where the underside of the cross-section is flat, the sides approximate
quadrants of a circle and the upper side approximates a (half) ellipse. The radius of
this ellipse along the horizontal axis is equal to the radius of the quadrant (quarter
of the circle). The filled dimensions of the geotextile tube can be approximated using
the mathematical formulae given below, and using the basic parameters shown in
Figure D.1.
Note: The best way to determine the shape of the geotextile tube is to use
the method described by Timoshenko [44] and which is used in several computer
programs. Bezuijen and Van Steeg [40] have shown that this formulation presents
excellent agreement with calculations and measurements. However, this method
requires the use of a computer and numerical calculations. When these are not
available, it is possible to make an estimate of the tube shape using the method
described below.
=
circumference/2
π
b
r
a
Figure D.1
Definition sketch of a filled geotextile tube.
