Evaluating the hydraulic conductivity of GCLs permeated with non-standard liquids

Shackelford, Charles D.; Benson, Craig H.; Tanaka, Katsumi; Edil, Tuncer B.; Lin, Lianzhen

doi:10.1016/s0266-1144(99)00024-2

Cited by 419 publications

(176 citation statements)

References 18 publications

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“…As shown by Petrov et al (1997b) and discussed by Shackelford et al (2000), these additional increases in effective stress have a relatively minor effect compared to other factors involved in hydraulic conductivity testing. These increases in effective stress result in effective stresses that most likely are at, or near, the "pre-consolidation" pressure produced by the thermally treated fibres in the GCL during hydration.…”

Section: Influentmentioning

confidence: 94%

“…As predicted by the Stern-Guoy model (van Olphen, 1977;Mitchell, 1993;Shang et al, 1994) this could potentially cause the double layer thickness to decrease. Shackelford et al (2000) demonstrated the potential inhibition of double layer expansion of a sodium bentonite by showing significantly higher free swell values for distilled water (36 mL) compared to a 0.025 M AlCl 3 solution (11mL). Depending on the initial hydration fluid and applied effective stress, this decreased double layer thickness could result in increases to a GCL's hydraulic conductivity or diffusion coefficient if present in a monofill application.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Aluminium migration through a geosynthetic clay liner

Lake

Cardenas²,

Goreham

et al. 2007

Geosynthetics International

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Water treatment plants (WTPs) can produce significant amounts of residual solids (i.e. sludge) as a result of coagulation, flocculation, clarification, and filtration processes to treat raw source water. In North America, alum is a common coagulant used in this process, resulting in the requirement for disposal of significant amounts of alum residual solids. Anticipated improved water quality treatment guidelines for trace metals such as arsenic in North America will result in more alum waste being generated in the future and hence increased pressure on water utilities to examine monofilling of alum-based residual solids to reduce waste management costs. GCLs are a potential cost-effective liner system for this type of application. However, there is currently a paucity of literature related to aluminium migration through GCLs.This paper presents results of GCL hydraulic conductivity, diffusion, and batch testing performed with a simulated WTP monofill leachate. Results of both short term and long term hydraulic conductivity tests show only modest increases in hydraulic conductivity, k, are observed for the tests conditions employed (k< 5x10 /s and a linear distribution coefficient, K d , of 30 mL/g. Batch testing is used to provide additional insight into the sorption behavior of aluminium with the bentonite from the GCL. Based on the limited results presented herein, it appears as if GCLs are suitable at maintaining low hydraulic conductivity values for at least 12 pore volumes of permeation with the high concentration alum residual monofill leachate simulated in this study. The information presented herein also provides WTP monofill designers with estimates of contaminant migration parameters necessary for establishing "alternative" GCL based liner designs.

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Section: Influentmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 97%

Aluminium migration through a geosynthetic clay liner

Lake

Cardenas²,

Goreham

et al. 2007

Geosynthetics International

View full text Add to dashboard Cite

show abstract

“…Ion exchange has been shown to occur for GCLs in the laboratory and field, and is generally more problematic for conditions involving low confining stress, lack of prehydration with clean water, wet/dry cycling, and ambient solutions with high ionic strength, multivalent cations, or extremes in pH (Shackelford et al 2000;Kolstad et al 2004;Meer and Benson 2007;Benson and Meer 2009;Scalia and Benson 2011). Several forms of commercial GCLs are available with different amounts and types of polymer additives, including both unreinforced and reinforced products.…”

Section: Gcl Productsmentioning

confidence: 99%

State-of-the-art report: GCL shear strength and its measurement – ten-year update

Fox

Stark

2015

Geosynthetics International

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This paper presents an invited update to our 2004 state-of-the-art report and provides a comprehensive source of information on the shear strength and shear strength testing of geosynthetic clay liners (GCLs). Essential concepts of shear stress-displacement behavior and shear strength are presented, followed by detailed discussions on the laboratory measurement of the shear strength of GCLs and GCL interfaces. The paper also provides recommendations for the selection of design strength envelopes for stability analyses and checklists to assist users in the specification of GCL shear testing programs. North American practice is emphasized and discussions are focused primarily within the context of landfill bottom liner and cover systems. Conclusions and recommendations are provided with regard to GCL shear strength behavior and current GCL strength testing practice, improvements for GCL strength testing are suggested, and future research needs are identified.

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“…Effective stress is a signifi cant variable that controls the behavior of bentonite (Shackelford et al 2000), decreasing both hydraulic conductivity and the susceptibility of bentonite to chemical alterations; because increasing the effective stress on a GCL decreases the void ratio within the bentonite layer. The hydraulic conductivity of the sodium bentonite used in most GCLs is on the order of 10 -9 cm/s when permeated with deionized water at stresses typical of cover applications (Rowe 2005).…”

Section: Introductionmentioning

confidence: 99%

Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw

Zhang

Wang

Zhou

et al. 2015

Archives of Environmental Protection

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Abstract:The objective of this paper is to evaluate the self-healing properties of a commercially-available geosy nthetic clay liner (GCL) using fl exible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penet rating fl aw and also on specimens permeated with distilled water and CaCl 2 solutions. The test results were presented and discussed. Exper imental results showed that the GCL with penetrating fl aw did not exhibit complete self-healing in the case of fl aw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl 2 solutions had a signifi cant infl uence on the hydraulic conductivity. The research fi ndings might be of interest to researchers and engineers who design liners for landfi lls and other liquid containment facilities.

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Evaluating the hydraulic conductivity of GCLs permeated with non-standard liquids

Cited by 419 publications

References 18 publications

Aluminium migration through a geosynthetic clay liner

Aluminium migration through a geosynthetic clay liner

State-of-the-art report: GCL shear strength and its measurement – ten-year update

Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw

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