A semi-analytical methodology for development of woven geotextile filter selection criteria

Geotextiles have been commonly used in geotechnical and environmental engineering projects to prevent erosion of soils in contact with the filter without impeding the flow of seeping water through the soil. Several empirical criteria incorporating varying factors of safety have been proposed for selection of geotextile filters. A probabilistic numerical filter model, named RETAIN, using image-based geotextile pore structure was developed for woven geotextile filters and is presented in this paper. The paper also summarizes a new methodology to propose filter selection criteria using the results of RETAIN. The proposed criteria based on this methodology and the existing empirical criteria from the literature were evaluated against the actual performance observed in the laboratory filtration tests on a silty sand specimen and a wide range of woven geotextiles. The results indicated that RETAIN can model the filtration behavior of silty sands and woven geotextiles, and the model output can be used to develop new geotextile selection criteria. The method is currently applicable to one type of soil; however, the method is rational, and the applicability of the methodology to other soils with a range of particle size distributions can be checked after conducting laboratory filtration tests on these soils.