Validation of the use of filter paper suction measurements for the determination of GCLs retention curves

Laboratory tests were carried out to study the suitability of the filter paper method to measure the suction of geosynthetic clay liners (GCLs). This issue was addressed under three axes: (i) comparison to previous works (ii) influence of the position of the GCL; and (iii) comparison to suctions obtained for geotextiles. Four different GCLs were used. Results obtained with filter paper showed a good agreement with previously published results. They also indicate that the position of the GCL does not affect the suction when the water content of the GCL ranges from about 10% to 115%. Finally, suctions obtained for GCLs differ from the suction obtained for geotextiles. These results suggest that the suctions measured concern the whole GCL and not only the geotextile in contact with the filter paper. This study concludes that the filter paper method can be used to measure a large range of suctions of the GCLs.