Permeability of Filter Layers on Stability of Rip-Rap Revetments Under Wave Attack

The stability of revetments under wave attack varies greatly with the type of underlying filter layers. Model tests on rip-rap revetments were performed by the BA W on different types of filter systems. The results of these tests have shown a clear influence of the filter layer permeability. The damage levels found in these model tests with different rip-rap thi9knesses and variation in stone si7.es are compared with damage calculations using the Hudson-criteria. The paper discusses the experiments and presents the results of a simulation with the computer program Steenzet/1 (Delft Geotechnics) as to whether the uplift pressures below the geotextile could have caused the decrease in revetment stability. The paper presents these results; useful conclusions for the design practice are given.