The effect of fine soil content on the filtration characteristics of geotextile under cyclic flows

摘要

The use of geotextiles as filters for revetments or embankments has become popular.nThe geotextile filter must be permeable enough to drain water effectively, but it also has to retainnthe soil particles to prevent them from being washed out. In the research on the filtration functionnof geotextiles, retention and permeability criteria have been proposed. Most of the research hasnconsidered conditions that are simpler than real in situ conditions, such as cyclic flows due to thenfluctuation of water table caused by sea waves, boats, or periodic drawdown of water for irrigationnpurposes. Moreover, soils with different fines contents will cause dissimilar soil erosion behaviournin a revetment that uses geotextiles. For this reason, a cyclic flow apparatus is adopted in thisnresearch to take account of the effect of overburden pressure and cyclic flows on soils. The soilnsamples are composed mainly of sand, with 0–10% fines content of silts and clays. The appliedncyclic flow periods range from long to short, in order to simulate a range of waves. The resultsnshow that the fines content has a significant effect on the filtration behaviour of a soil–geotextilensystem. In addition, the normal pressure and cyclic flow period have an influence on thenperformance of the geotextile filter.