Starting in the 1930’s, many research projects have been performed with the intent to establish rules, which can be used to design granular, geometrically closed filter structures for hydraulic structures. However, for the vast majority of these research projects, the filter structure was loaded by uniform flow, either in the parallel or perpendicular direction. This means that, while for filters under flow loading multiple design options and diagrams are available, the knowledge on design rules for sloped, closed filters under wave loading remained limited. These knowledge gaps mean that, in design practice, often the design criteria for closed filters under flow loading, for instance the original criterion by Terzaghi, are used for the design of closed filters under wave loading, while these have not yet been experimentally verified for this use case.

This thesis combines model test results from two historically performed experiment programs on sloped, closed granular filters under wave loading with new experiments, which were conducted especially for this thesis. By analyzing the results from these three research projects, it was found that commonly used interface stability criteria for closed granular filters under flow loading are not valid for use in the case of a sloped, closed granular filter under wave loading. Based on the test results from the three test programs that were analyzed, a new interface stability criterion for sloped, closed granular filters under wave loading is proposed.