Predicting the mechanical colmatation of nonwoven geotextiles

Colmatation, in which the conductive channels are clogged with solid microparticles, leads to the loss of performance of filtering devices used in everyday life and technology. This creates a need to develop criteria to assess the likely need to replace the working parts of filters. However, existing engineering methods are not enough to calculate the change in the degree of filter clogging during its operation under certain conditions. Based on this, a new theoretical and experimental approach to solving this problem is proposed. The pore structure of thin fibrous-porous filters that differ in their structural characteristics, production methods, and materials was studied. Nineteen samples belonging to three types were selected for experiments. The first type is a filter material of polyethylene fibers obtained by pneumoextrusion. The second type is a nonwoven geotextile material made of thermally bonded polypropylene fibers. The third type is a nonwoven geotextile material made of thermally bonded polypropylene fibers. Using the photo method, the scattering of calibrated soil particles, and approximation by a power function, integral curves of the pore diameter distribution were obtained for these materials. As a result, an experimental dependence was established, which makes it possible to predict the degree of filter clogging. This allows us to calculate the area of unclogged pores that will provide the filtration capabilities of the filter throughout its service life. A method for determining the area of unclogged filtration channels per unit of filter area is proposed. Specific examples illustrate the relationship between the percentage of residual free cross-section of channels in a nonwoven geotextile material and the ability to perform its filtering function effectively.