Research into alternative method to confine the risk of piping
In September, Deltares will carry out a test with geotextile, at the IJkdijk location in Groningen. This special textile will be placed vertically into the test dike to see if the process of piping can be confined. If the test is successful, geotextile could well be a good alternative to the current piping measures: broadening dikes or placing sheet pilings.
Deltares was commissioned to carry out this study by the Water Board Rivierenland, who need to strengthen several kilometres of dikes to confine the risk of piping. The test will be supported by the Room for the River Programme.
Piping has an enormous impact on the stability of a dike and it is therefore absolutely essential to confine this process. Previous studies have shown that it is one of the most important dike failure mechanisms. Piping is a common occurrence in The Netherlands. It occurs at the sand-clay interface, when water levels are high. The resulting pressure can force water to seep through the base of a dike. This water may take grains of sand with it, creating tubular openings (pipes) under the dike, which get bigger and bigger, endangering the stability of the structure. If piping is not confined, it can weaken the dike with the result that it can sag and, in the worst case, cause it to collapse.
According to Ulrich Förster, a dike technology specialist at Deltares, this geotextile test can lead to an important alternative for dealing with piping. “Current measures are expensive and take up a lot of space. Therefore, it would be excellent if the use of geotextile turns out to be a good alternative as it is cheaper, easy to install and needs no extra space.”
Geotextile is already in use in hydraulic engineering, but using it to prevent piping is new. Förster: “The first lab tests have shown promising results and expectations are high. Now we are going to test the textile in the IJkdijk, where we can optimally imitate the natural circumstances. If this test is also successful, the textile will be tested at a Rivierenland dike section early next year.
Published:24 July 2012