Self healing capacity of geosynthetic clay liners and influencing factors

Sari, Kartika; Chai, Jinchun

doi:10.1016/j.geotexmem.2013.08.006

Cited by 45 publications

(24 citation statements)

References 22 publications

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“…The results of overburden pressure () and apparent permittivity () of the damage holes with different size have been reported by Sari and Chai 14) already. In this study, the effect of the types of liquid is investigated mainly under the condition of diameter …”

Section: (3) Conditions Investigatedsupporting

confidence: 56%

“…of CaCl 2 case is almost 2 orders higher than that of the ethanol case. To further quantify the self-healing capacity, a parameter of area healing ratio ( h ) is defined as 14) :…”

Section: Resultsmentioning

confidence: 99%

“…5(a) and (b) indicates that the general tendency of the effect of the types of liquid is not changed by the overburden stress. Sari and Chai 14) discussed that value has two effects. One is squeezing hydrated bentonite into a damage hole, which can increase the self-healing capacity of a GCL.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Type of Leachate on Self-Healing Capacity of Geosynthetic Clay Liner

Chai

Sari

Hino

2013

Geosynthetics Engineering Journal

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The effect of type of leachate (liquid) on self-healing capacity of the geosynthetic clay liners (GCLs) has been investigated by laboratory leakage rate tests. Four types of liquids, namely, tap water, 10 g/l NaCl solution, 100 ml/l ethanol solution and 11.1 g/l CaCl 2 solution were used. The test results indicate that the types of liquid have a significant effect on self-healing capacity of GCLs through the influence on the amount of hydration induced expansion of the bentonite inside GCLs. Free swelling index of the bentonite with the corresponding liquid can be used to evaluate the relative effect of the liquid. Also, for the conditions investigated, it seems that overburden stress () on the GCL samples does not change the general tendency of the effect of the types of liquid.

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Section: (3) Conditions Investigatedsupporting

confidence: 56%

“…of CaCl 2 case is almost 2 orders higher than that of the ethanol case. To further quantify the self-healing capacity, a parameter of area healing ratio ( h ) is defined as 14) :…”

Section: Resultsmentioning

confidence: 99%

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Effect of Type of Leachate on Self-Healing Capacity of Geosynthetic Clay Liner

Chai

Sari

Hino

2013

Geosynthetics Engineering Journal

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“…For example, Sari and Chai (2013) showed that bentonite-free holes, 40 and 50 mm in diameter, did not self-heal (after permeation with tap water at a normal stress of 200 kPa) in a geotextile encased, needle-punched, thermally treated GCL (with a slit-film woven lower geotextile and nonwoven upper geotextile and granular bentonite). As a result, the most significant implication of the observed erosion features would be the loss of the low permeable component of the composite GMB/GCL liner which would negatively impact the potential leakage rates through the composite liner if a hole were to occur at or near the erosion feature.…”

Section: Practical Implicationsmentioning

confidence: 99%

Observations of bentonite erosion from solar-driven moisture migration in GCLs covered only by a black geomembrane

Take

Brachman

Rowe

2015

Geosynthetics International

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Manufacturers of geosynthetic liner materials recommend that composite geomembrane/geosynthetic clay liners (GCLs) be covered in a timely fashion to avoid potential issues that may arise under the action of long-term solar exposure. In this paper, field evidence of a new, never before reported solar-exposure driven damage mechanism for GCLs covered only by a black geomembrane and left exposed for more than 3 years is presented. Solar exposure can give rise to a large daily variation in geomembrane temperature, which causes a moisture cycle within the interface between the geomembrane and GCL resulting in the formation and flow of condensed moisture beneath the geomembrane. All four of the GCL products investigated at the Queen's University Environmental Liner Test Site were shown to have experienced significant bentonite erosion after 4.7 years of exposure. Erosion was identified in the field through a tactile survey of GCL panels in which the stiffness response of the GCL to touch was used to identify eroded zones. A change in the colour of the GCL, although useful to identify possibly eroded zones in some GCL products, proved ineffective in others. Erosion features were observed with widths up to and exceeding 200 mm across, making them unlikely to undergo self-healing upon hydration and application of normal stress. As a result, the observed erosion features would have severe adverse consequences for leakage rates through the GCL component of a composite liner barrier system. These observations provide yet another strong motivation for timely covering of composite landfill liner systems.

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“…Numerous laboratory investigations have examined the effect of several factors on the hydraulic performance of GCLs such as cation exchange, interaction with different permeants, wet-dry cycles, and freeze-thaw cycles (e.g., Shan and Daniel 1991;Boardman and Daniel 1996;Petrov and Rowe 1997;Lin and Benson 2000;Shackelford et al 2000Shackelford et al , 2010Jo et al 2005;Lee et al 2005;Rowe et al 2006;Bouazza et al 2007;Brown and Shackelford 2007;Benson and Meer 2009;Lange et al 2010;Rosin-Paumier et al 2011;Rosin-Paumier and Touze-Foltz 2012;Rowe and Abdelatty 2012;Bradshaw et al 2013Bradshaw et al , 2016Mazzieri et al 2013;Rowe and Hosney 2013;Sari and Chai 2013). There have been far fewer studies examining the hydraulic performance of GCLs after a period of field exposure in applications such as covers or caps under low applied stress and these studies have given rise to some apparently inconsistent findings as discussed below (James et al 1997;Benson et al 2007Benson et al , 2010Meer and Benson 2007;Benson 2010a, 2011;Buckley et al 2012;Hosney and Rowe 2013).…”

Section: Introductionmentioning

confidence: 99%

Insight into hydraulic conductivity testing of geosynthetic clay liners (GCLs) exhumed after 5 and 7 years in a cover

et al. 2017

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Four geosynthetic clay liners (GCLs) serving as single liners were exhumed from below 0.7 m of silty sand on a 3:1 (horizontal:vertical) north-facing slope at the QUELTS site in Godfrey, Ontario, after 5 and 7 years. The 300 mm GCL overlaps with 0.4 kg/m supplemental bentonite were all physically intact. The exchangeable bound sodium was completely replaced with divalent cations. The GCL with the smallest needle-punched bundle size (average of 0.7 mm) and percentage area covered by bundles (4%) maintained low hydraulic conductivity (k) when tested under 0.07-1.2 m head with 10 mmol/L CaCl 2 solution as the permeant. For GCLs with larger bundles (1.1-1.6 mm) and higher percentage area covered by bundles (9%-14%), k was low when the head was low (0.07 m). Once the applied head increased, k increased by 1-4 orders of magnitude depending on the (i) hydraulic gradient, (ii) size and number of the needle-punched bundles, and (iii) structure and mass of the bentonite per unit area. The results suggest that the GCLs can perform effectively as a single hydraulic barrier in covers providing that the head above the GCL is kept low (e.g., by a suitable drainage layer above the GCL).Key words: geosynthetic clay liner, cover, overlaps, cation exchange, hydraulic conductivity, field study. Résumé :Quatre couches d'argile géosynthétiques (CAG) agissant comme des parois uniques ont été exhumés d'une profondeur en dessous de 0,7 m sur un sable limoneux de 3 : 1 (horizontale : verticale) au versant nord au site QUELTS dans Godfrey, en Ontario, après 5 et 7 ans. Les 300 mm de CAG se superposent au 0,4 kg/m de bentonite supplémentaire qui est physiquement intact. Le sodium lié échangeable a été complètement remplacé par des cations divalents. Le CAG avec la plus petite taille de paquet aiguilleté (moyenne de 0,7 mm) et le pourcentage de la superficie couverte par des faisceaux (4 %) a maintenu une faible conductivité hydraulique (k) lors de l'essai sous une tête de 0,07 à 1,2 m avec une solution 10 mM de CaCl 2 comme perméant. Pour les CAG avec de plus grands faisceaux (1,1 à 1,6 mm) et un pourcentage plus élevé de la zone couverte par des faisceaux (9-14 %), k est faible quand la tête était faible (0,07 m). Une fois que la tête appliquée a augmenté, k a augmenté de 1 à 4 ordres de grandeur en fonction (i) du gradient hydraulique, (ii) du nombre et de la taille des faisceaux aiguilletés et (iii) de la structure et la masse de la bentonite par unité de surface. Les résultats suggèrent que le CAG peut fonctionner efficacement comme une seule barrière hydraulique dans des couvercles à condition que la tête au-dessus du CAG soit maintenue à un niveau bas (p. ex., par une couche de drainage approprié au-dessus du GCL). [Traduit par la Rédaction] Mots-clés : couche d'argile géosynthétique, couvercle, chevauchements, échange de cations, conductivité hydraulique, étude sur le terrain.

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Self healing capacity of geosynthetic clay liners and influencing factors

Cited by 45 publications

References 22 publications

Effect of Type of Leachate on Self-Healing Capacity of Geosynthetic Clay Liner

Effect of Type of Leachate on Self-Healing Capacity of Geosynthetic Clay Liner

Observations of bentonite erosion from solar-driven moisture migration in GCLs covered only by a black geomembrane

Insight into hydraulic conductivity testing of geosynthetic clay liners (GCLs) exhumed after 5 and 7 years in a cover

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