Improved design criteria for nonwoven geotextile filters with internally stable and unstable soils

• Published in: Geotextiles and geomembranes Vol. 50; no. 6; pp. 1120 - 1134
• Main Authors: Kalore, Shubham A., Sivakumar Babu, G.L.
• Format: Journal Article
• Language: English
• Published: Essex Elsevier Ltd 01.12.2022; Elsevier BV
• Subjects: Clogging; Constrictions; Design criteria; Design improvements; Filters; Filtration; Fines; Fluid filters; Geotechnical fabrics; Grain size; Grain size distribution; Hydraulic conductivity; Hydraulics; Limit states; Nonwoven geotextile; Random variables; Retention; Soils; Clogging; Hydraulic conductivity; Filtration; Retention; Nonwoven geotextile
• ISSN: 0266-1144; 1879-3584
• DOI: 10.1016/j.geotexmem.2022.07.004

In geotextile filtration, the soil fines are either accumulated near the interface, clogged, or washed out, which primarily depends on the grain size distribution (GSD) of soil and the constriction size distribution (CSD) of geotextile. Also, the movement of fines significantly affects the flow capacity of geotextile. Currently, the retention requirement is satisfied based on representative grain and opening sizes, whereas the hydraulic conductivity and clogging requirements are satisfied considering the properties of virgin geotextile. This paper presents a probabilistic retention criterion considering the grain and constriction sizes as random variables. The influence of geotextile thickness is incorporated into the criterion by considering the number of geotextile constrictions in a filtration path. A theoretical approach to predict CSD is presented if the measured data is unavailable. For hydraulic conductivity and clogging requirements, a criterion is presented considering the expected partial clogging of geotextile, which is predicted based on the semi-analytical approach. The limit states for the developed criteria are evaluated based on the wide range of experimental data from the current study and published literature. The developed design criteria are applicable to internally stable and unstable soils, which offers an improvement in design compared to the existing criteria in practice. •Gradient ratio tests were performed on a wide range of soils and commercially available geotextiles.•A probabilistic retention criterion is developed by considering the grain and constriction sizes as random variables.•A hydraulic conductivity criterion is developed by considering the expected partial clogging of geotextile.•A procedure for geotextile design is proposed based on the developed criteria and limit states of failures.