Field measurements of overlap reductions for two reinforced fabric-encased GCLs

Two GCLs reported to have experienced significant shrinkage at other locations are examined on both a 3H:1V south facing slope and a relatively flat base on a silty-sand. The GCLs were overlapped by 300 mm with 400 g/m of supplemental bentonite and covered by a black 1.5 mm HDPE geomembrane to form a composite liner which was left exposed in a full-scale field test embankment for a period of almost five years. It is shown that despite the relatively uniform exposure conditions, shrinkage is highly variable with a maximum shrinkage of GCL A being 165 mm on the slope and 415 mm on the base while GCL B shrunk by up to 75 mm on the side slope and only up to 25 mm on the base. The dominant role played by variable overlap stick and heterogeneity to the locations where the overlaps are re-wetted are discussed. Based on this study of shrinkage and a related study of down-slope erosion at the same site, it is concluded that neither GCLs A and B should not be left in exposed composite liners when they can be subjected to thermal cycles that can lead to hydration and dehydration of the GCL.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author