Hydraulic Performance of Overlapped Geosynthetic Clay Liner Seams Requiring Field-Applied Supplemental Bentonite

Brachman, R. W. I.; Joshi, Prabeen; Rowe, R. Kerry

doi:10.1061/(asce)gt.1943-5606.0001566

Cited by 9 publications

(1 citation statement)

References 21 publications

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“…This level of shrinkage could substantially reduce the effectiveness of the seal even if no gap formed, especially when the overlap coincided with a wrinkle (Joshi et al 2017). For example, Brachman et al (2016) showed that a 50 mm overlap with no engaged supplemental bentonite had a leakage a million-fold higher than that for a 150 mm overlap with engaged supplemental bentonite. Based on the magnitude of reported shrinkage (Table 1), it was decided that at QUELTS a more conservative approach would be adopted wherein all overlaps between adjacent panels were 300 mm (i.e., twice that usually used with these GCLs) and no reliance was placed on the melted groove but rather an additional 400 g/m of supplemental bentonite was placed at each overlap ( Figure 2).…”

Section: Gcls Examined Herein and Monitoring Detailsmentioning

confidence: 99%

Field measurements of overlap reductions for two reinforced fabric-encased geosynthetic clay liners (GCLs)

2018

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Abstract: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.

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Section: Gcls Examined Herein and Monitoring Detailsmentioning

confidence: 99%

Field measurements of overlap reductions for two reinforced fabric-encased geosynthetic clay liners (GCLs)

2018

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Effect of overburden confining stress on hydraulic performance of geosynthetic clay liners (GCLs)

Weerasinghe

Gallage

Dawes

2021

Heliyon

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Geosynthetic clay liners are a rapidly evolving geosynthetic product used in most hydraulic barrier applications in the geo-environmental industry. Continuous research has led to new insights to overcome the shortcomings faced in deploying GCLs in the field. These include shrinkage due to shear failure on side slopes, the effect of temperature variation, and inadequacy of minimum timely confinement to achieve optimum hydraulic performance. This paper presents previous experimental data and an additional dataset from this research gathered to observe the effect of overburden confining stress on GCL hydraulic conductivity and how the findings can be used to predict the performance of a geosynthetic clay liner for a given field application. An inverse power relationship is identified between these two parameters along with the reduction in the order of the degree of hydraulic conductivity depending on the permeant material passing through. A relationship is determined to estimate the GCL hydraulic conductivity as a function of the overburden confining stress, given that it is pre or post hydrated and the permeant liquid passing through the product. It is proposed that the relationship can be used to predict the GCL hydraulic performance in the field and provide guidance in improving the serviceability of hydraulic barrier designs.

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Factors affecting the hydraulic performance of a geosynthetic clay liner overlap

Weerasinghe

Gallage

Dawes

et al. 2020

Journal of Environmental Management

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Hydraulic Performance of Overlapped Geosynthetic Clay Liner Seams Requiring Field-Applied Supplemental Bentonite

Cited by 9 publications

References 21 publications

Field measurements of overlap reductions for two reinforced fabric-encased geosynthetic clay liners (GCLs)

Field measurements of overlap reductions for two reinforced fabric-encased geosynthetic clay liners (GCLs)

Effect of overburden confining stress on hydraulic performance of geosynthetic clay liners (GCLs)

Factors affecting the hydraulic performance of a geosynthetic clay liner overlap

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