The paper presents the test results of the hydraulic characteristics of artificially clogged three types of nonwoven geotextiles. The specimens were artificially clogged in the laboratory according to the procedure created by authors by using a device used for determination of water permeability characteristics normal to the plane under load. In the central part of this device there was a soil layer (siSa) and beneath a nonwoven geotextile layer to allow the water vertical flow through the composite. Because of the water was flowing at constant time and certain water head, the specimen could be clogged. The artificial clogging procedure was created to reproduce natural in situ conditions. To observe mechanism of the artificial clogging 3D tomography was also used. The obtained results showed that the artificial clogging has an influence on the hydraulic characteristics of geotextiles. A significant reduction of the nonwoven geotextiles permeability due to physical artificial clogging was observed. The flow velocity and the velocity index for a head loss of 50 mm was constant after three hours of artificial clogging and around three times lower than at the beginning. It means that the specimen was clogged after three hours according to the procedure. It strongly depends on physical parameters of the geotextile, especially on characteristic opening sizes. If characteristic opening size was higher, the decrease of permeability was lower.
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