Experimental study on filtration performance of geotextile filter used in emergency rescue of dike piping

Abstract

Geotextiles, as a type of common filtration material, have broad prospects in emergency rescue of dike backward erosion piping (BEP). To investigate the filtration performance of geotextile in BEP emergency rescue, several experiments were conducted using nonwoven and woven geotextiles to simulate the process of rescuing BEP with geotextiles. The influence of geotextile specifications and types on hydraulic compatibility of the filter system was analyzed, and the clogging mechanism of geotextile during dealing with BEP was revealed at a microscopic level. The results showed that the nonwoven geotextile filter with an equivalent pore size of 0.103 mm had a gradient ratio value of less than 3, and it had a highest flow rate of 260 mL/min. Increasing the thickness and pore size of nonwoven geotextiles within a certain range helped enhance their anti-clogging ability. The main mechanism of clogging in nonwoven geotextiles was the deposition of fine sand particles on their surface, forming a layer of low permeability soil. Plain woven geotextiles experienced severe clogging with a 42% reduction in flow rate, and it was not suitable for rescuing BEP. The clogging mechanism of woven geotextile involved the blocking of horizontal water passages by fine sand particles.