Characterisation of geotextiles water retention using a modified capillary pressure cell

This paper presents water retention data, on the drying path, of a non-woven polyester geotextile obtained from a modified capillary pressure cell. The results were evaluated and compared to a hanging column test results. A good correlation was found between the two test methods. The modified capillary cell allowed the testing to be conducted in a very short time compared with the conventional hanging column test. The unsaturated hydraulic characteristics of the geotextile were determined using the modified van Genuchten equations (Hydrus-1D). The measured retention data were also fitted to the Fredlund and Xing mathematical equations. Both the modified van Genuchten equations and Fredlund and Xing equations were found to be in close agreement with experimental retention data. The numerical analysis shows that the K-suction curves starting from zero suction levels are better estimated by the modified van Genuchten equations due to the continuity and smoothness of the conductivity function.