Abstract: The clogging of geotextiles as a filtration is a common problem in engineering practice. In this paper the shortcomings and limits of conventional gradient ratio test device and method in current specifications for geotextile clogging are discussed. Moreover, improvements on test device and test method are presented, and the rationality of such improvements is analyzed. A group of tests show that the value of gradient ratio based on the existing text devices cannot directly reflect the clogging of geotextiles themselves, while the improved device can provide convenient independent measurements of soil’s permeability coefficient and geotextile’s permeability coefficient. By this way the actual clogging state of geotextile can be monitored clearly.

Key words: geotextiles, clogging, permeability coefficient, gradient ratio, test device