There is a great number of research reports and publications on filtration of geotextiles and their application in · revetment structures. But still, there is a misunderstanding about the function of geotextiles in the total design of these structures, especially in comparison with the granular filters. The general principles of designing of revetments incorporating geotextiles are reviewed. It is shown that simply replacing a granular filter by a geotextile leads to geotechnical instability, especially because the layer thickness and weight of the two. are very different.
Further it appears that a thicker granular filter gives a larger geotechnical stability, but a lower cover layer stability (uplift of blocks). The conclusion is therefore that the wave loads must be distributed (balanced) adequately over the sand (shear stress) and the cover layer (uplift pressure). Too zyruch emphasis on one failure mechanism can lead to another mechanism.
KEYWORDS: (block-)reve(ments, geotextiles, design, bank protection.