Geotextile positioned vertically in a dike can stop piping. That has been proven by an experiment with the textile on IJkdijk in Bellingwolde (the Netherlands).
Geotextile has been used in hydraulic engineering for some time now but using it for piping is new. The experiment has shown for the first time in the field that geotextile can actually stop piping. Deltares conducted the test in the last week of September for the Rivierenland water authority with co-financing from the ‘Room for the River’ programme.
For the purposes of the experiment, the special textile was installed over a width of 15 m and a height of 0.5 m in the clay layer of the dike. The special geotextile ‘GeoDetect filter and detection system’ was supplied by Ten Cate.
Once the textile was in place, the pressure on the dike was increased to induce piping. Clear piping was soon seen below the clay dike on the downflow side of the textile but the geotextile was successful in stopping the further development of the piping channel. The geotextile stopped piping for eight days, after which the experiment was terminated.
Ulrich Förster, a Deltares dike specialist , was closely involved with the test. He is very enthusiastic about the result: ‘ We had already conducted lab trials with the geotextile and the results were very promising. So we had high hopes for this experiment and we haven’t been disappointed. Even less sand and clay than I expected was rinsed out. We stopped after eight days because, in practice, that is usually how long high water lasts, with a risk of piping as a result.’
Now the experiment has been successful, the Rivierenland water authority will be looking to see whether the textile can be tested next year on a longer section of dike in the Rivierenland area.
The Rivierenland authority has to upgrade many kilometres of dike because of the risk of piping, a process that has a major impact on the stability of a dike. The current measures, the widening of dikes or the installation of sheet piling, are expensive and they take up a lot of space. Geotextile could be a good alternative: it is cheaper, easier to install and it doesn’t take up any extra space.
[mappress]
Press Release, October 12, 2012