Abstract: Geotextiles have been successfully used as filter materials in geotechnical practice of different fields. Due to the complexity of the application environment of geotextiles and the unique characteristics of the protected soil, studying the filtration mechanism of geotextiles as a filter is of important engineering application value. In the present paper, the formation mechanism of soil's “self-filtering layer” in “soil-geotextile” system and the filtration characteristic of geotextiles are summarized. The major factors affecting the filtration performance of geotextiles are analyzed, and the differences in the criteria of soil retention, water permeability, and anti-clogging of geotextiles are also discussed. Moreover, limits in existing studies and applications of geotextiles as filter materials are expounded. Such limits include the filtration characteristics of geotextile filtering fine-grained soil, and the application of filtration criteria in practical engineering. To ensure the normal function of geotextile filtration, targeted criteria for geotextile filtration should be established in line with application environment.

Key words: geosynthetics, geotextile, filtration, filter criterion, influence factors