Filtration properties of geotextiles

Abstract

In the past years,many models, and laboratory techniques and apparatus have been developed to examine the filtration properties of the geotextiles. To select the proper geotextile which will be used in drainage and filtration, the indicative pore size of the geotextile and granulometric curve of the soil must be determined at the begining. The objective of this thesis is to construct the (Saturated Silty Soil + Geotextile + Wet Gravel Filter) system and, to determine the coefficient of permeability of this system. These tests are performed to determine when the clogging happens. For this reason, two types of silty soil, and four types of nonwoven geotextiles have been used.California Bearing Ratio (CBR) test molds have been used as test apparatus. Into the lower part of the mold, gravel filter has been placed, and geotextile has been placed between the upper and lower part of the mold, and saturated silty soil has been filled into the upper part of the mold.The coefficient of permeability of this system has been determined, and Number of Test versus system permeability curves have been drawn. The test results have shown that, the coefficient of permeability of the system remains approximately constant after a definite time.