A parametric database study of no-erosion filter tests

Modern filter design procedures for embankment dams respect criteria stemming from no-erosion filter (NEF) tests. The widespread application of NEF testing has provided experimental evidence of some deviations from the established filter criteria. This paper provides a complementary update to similar database studies of NEF test results. A large database of NEF tests, consisting of 258 group I and group II core soils (i.e. having more than 35% fines content) was analysed and the effects of various core soil characteristics (gradation, fines content, clay content, plasticity index and dispersivity) on experimentally defined no-erosion boundary filters were assessed. The database is unique, as it compiles the largest set of NEF test results. Through rigorous statistical and parametrical analysis, this paper critically compares current filter design criteria with experimental results and provides new insights that may assist and improve current procedures of critical filter design.