The influence of seating time on water flow of nonwoven geotextiles in permeability tests

Determining the main hydraulic parameters of geotextiles is undoubtedly necessary for correctly selecting geotextiles in civil engineering constructions. Proper laboratory testing and subsequent determination of these parameters is important to ensure the effectiveness of the drainage system, or at least in avoiding the phenomenon of clogging. This paper presents the results of a study of the effect of seating time on the water flow of needle-punched nonwoven geotextiles. Seating time is a period during which the product is maintained under constant compressive stress before a measurement is made. The study results show that the water flow of geotextiles decreases with increasing seating time. It was confirmed that when a nonwoven geotextile sample is subjected to a given normal compressive stress, the water flow of the nonwoven geotextile does not immediately decrease to a final value. Moreover, the relationship between geotextiles’ physical and hydraulic parameters and the seating time was shown.