A method to assess risk reduction when utilizing geosynthetic clay liners (GCLs) with compacted soil liners

2011 ◽  
Vol 48 (1) ◽  
pp. 146-161 ◽  
Author(s):  
W. T. Menzies ◽  
G. A. Fenton ◽  
C. B. Lake ◽  
D. V. Griffiths
Keyword(s):  
Hydraulic Conductivity ◽  
Analytical Solution ◽  
Compacted Clay ◽  
Geosynthetic Clay Liners ◽  
Probability Of Exceedance ◽  
Compacted Soil ◽  
Liner System ◽  
Soil Liners ◽  
Soil Liner ◽  
Random Field Simulation

This paper presents an analytical solution developed to estimate probabilities of “failure” or advective flux “exceedance” for the case of a spatially variable geosynthetic clay liner (GCL) situated over a spatially variable compacted soil liner (CSL). The risk of utilizing such a liner system is assessed relative to a regulatory compacted clay-based soil liner. The analytical solution developed is validated over a range of parameters against random field simulation using the Local Average Subdivision method, and the analytical solution is shown to be in good agreement with simulation. The analytical solution is then used to examine the “probability of exceedance” for a spatially variable GCL and CSL combined liner system. It is shown that the use of a GCL can potentially result in a low probability of exceedance when used with a spatially varying, high hydraulic conductivity CSL. The risk of exceedance generally decreases as the hydraulic conductivity of the CSL decreases. An example problem is presented to demonstrate the capabilities of the analytical solution.

The Influence of Compaction Effort in Laterite Soil with the Appearance of Sodium Bentonite as a Soil Liner

2017 ◽  
Vol 873 ◽  
pp. 198-202
Author(s):  
Nor Azizah Che Azmi ◽  
Mazidah Mukri ◽  
Nur Aisyah Kasim ◽  
Asmawati Che Hasan ◽  
Nazri Nasir
Keyword(s):  
Hydraulic Conductivity ◽  
High Strength ◽  
Environment And Public Health ◽  
Health Issues ◽  
Laterite Soil ◽  
Sodium Bentonite ◽  
Liner System ◽  
Soil Liners ◽  
Soil Liner ◽  
Positive Results

Soil liner which is placed at the foundation of a landfill is very important in order to isolate waste materials and leachate from the environment. However, if not properly managed, the leachate can beriskytothe safety and serviceability of which are directly related to the environment and public health issues. Soil liners were proposed to minimize leachate egress and prevent ground pollution. In soil liner design, it is important to compact the layer properly in order to achieve low hydraulic conductivity and high strength of soil. In this study, different percentages of sodium bentonite were added to laterite soil to act as soil liner to stabilize the liner system. Sodium bentonite can easily absorb water more than a hundred percent of its weight. Thus, the sodium bentonites were chosen to be mixed with laterite soil. The differentpercentagesof sodium bentonite used are 5%, 10%, 15% and 20%. This research was carried out asan attempt to see the compaction effort for laterite soil mixedwith sodium bentonite. The outcomesof this study give positive results due to the potential of sodium bentonite to fulfill spaces in between soil particles. It is also found that sodium bentonite influences the resistance properties, hydraulic conductivity and the strength of soil.

Study on the Hydraulic Conductivity of Sand-Bentonite mixtures used as Liner System of Waste Landfill

2011 ◽  
Vol 194-196 ◽  
pp. 909-912 ◽  
Author(s):  
Si Fa Xu ◽  
Zhe Wang ◽  
Yong Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Layer ◽  
Low Permeability ◽  
Test Results ◽  
Natural Clay ◽  
Compacted Soil ◽  
Waste Landfill ◽  
Liner System ◽  
Flexible Wall ◽  
Soil Liner

A liner system such as liner sheet underlying impermeable soil layer having hydraulic conductivity less than 1*10-7 cm/s and a thickness larger than 100 cm is often used in china. As there is very little natural clay having such low permeability, bentonite is usually mixed into sand to decrease the permeability. In this paper, the compaction tests and permeability testing using flexible-wall permeameter are conducted. The test results show that the value of critical benonite ratio depends on bentonite ratio, and the hydraulic conductivity of the sand mixed with critical bentonite ratio for distilled water shows of the order of 1*10-8 cm/s that satisfies the china standard requested as compacted soil liner of waste landfill. Finally, the permeability testing used leachate including calcium component was conducted.

scholarly journals Computer Modeling Approach of Leachate Flow in Compacted Laterite Soil Liner

2018 ◽  
Vol 250 ◽  
pp. 01001
Author(s):  
Yamusa Bello Yamusa ◽  
Noraliani Alias ◽  
Kamarudin Ahmad ◽  
Radzuan Sa’ari ◽  
Loke Kok Foong
Keyword(s):  
Computer Software ◽  
Laterite Soil ◽  
Waste Containment ◽  
Compacted Soil ◽  
Saturation Intensity ◽  
Sanitary Landfills ◽  
Soil Liners ◽  
Image Technique ◽  
Soil Liner ◽  
Non Destructive

The use of hydraulic barriers in sanitary landfills has become an impeccable means of protecting the groundwater system from leachate. A question to be asked is, can these barriers continue to impede the migration of leachate over a long period? This paper investigates the phenomenon of leachate migration in compacted laterite soil used as liner in sanitary landfills. An experiment was carried out using laterite soil compacted at optimum moisture content using Standard Proctor energy. Leachate was poured on the compacted soil in an acrylic column and its migration was monitored using Digital Image Technique (DIT). The DIT capture photographic images at successive intervals of time which were fed through an image processing code to convert them to hue-saturation-intensity (HSI) format with the help of Surfer and Matlab computer softwares. Subsequently, PetraSim computer software was applied to predict the velocity behavior. The predicted velocity value shows that the laterite soil is compatible with the leachate and can be used as soil liner. The outcome of this study would enable designers to use non-destructive method to monitor and predict leachate migration in compacted soil liners to simulates leachate migration in waste containment applications.

Behavior of Geosynthetic Clay Liners due to the Migration of Heavy Metal

2014 ◽  
Vol 989-994 ◽  
pp. 433-436 ◽  
Author(s):  
Jing Jing Fan
Keyword(s):  
Heavy Metal ◽  
Low Cost ◽  
Compacted Clay ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Composite Liner ◽  
Landfill Liner ◽  
Low Leakage ◽  
Liner System ◽  
Underlying Soil

To protect the underlying soil and groundwater from landfills, the landfills are commonly lined with layered liner systems. Geosynthetic clay liners (GCL) have been increasingly used in the landfill liner systems to substitude the traditional compacted clay liners (CCL) because of their low cost, easily construction behavior and low leakage rate. To study the behavior of the GM+GCL liner system used in China due to the migration of Pb2+, we introduce in detail GM+GCL liner systems proposed by the Chinese specification. Then one dimensional finite layer model is used to investigate the anti-pollution behavior of the CM+GCL composite liner systems, with the focuses on the heavy metal Pb2+. It could be concluded that the main migration way through the GM+GCL composite liner system is that the transport of Pb2+through a GM+GCL composite liner system of a landfill cover takes place primarily through the holes in the GM. The findings provide useful reference for preventing, controlling and treating groundwater pollution in the GM+GCL liner system technically and scientifically.

Effect of freeze–thaw on the hydraulic conductivity and morphology of compacted clay

1993 ◽  
Vol 30 (2) ◽  
pp. 236-246 ◽  
Author(s):  
Majdi A. Othman ◽  
Craig H. Benson
Keyword(s):  
Hydraulic Conductivity ◽  
Three Dimensional ◽  
Compacted Clay ◽  
Clay Liners ◽  
Overburden Pressure ◽  
Thin Sections ◽  
Freeze Thaw ◽  
State Of Stress ◽  
Soil Liners ◽  
Compacted Clays

Several studies have shown that freeze–thaw causes changes in the hydraulic conductivity of compacted clays. Cracks formed by ice lensing and shrinkage cause the hydraulic conductivity to increase. In this paper, changes in hydraulic conductivity are related to changes in morphology. Photographs of thin sections of frozen specimens show that ice lenses form in compacted clay during freezing in a closed system. Photographs also show that similar ice structures are obtained for one- and three-dimensional freezing, which explains why similar hydraulic conductivities are obtained for both conditions. The photographs also show that a significant network of cracks forms in a single cycle of freeze–thaw. With additional cycles, new ice lenses are created and thus the hydraulic conductivity continues to increase. However, after about three cycles the number of new ice lenses becomes negligible and hence further changes in hydraulic conductivity cease. The temperature gradient and state of stress affect morphology and hydraulic conductivity of compacted clays subjected to freeze–thaw. At larger temperature gradients, more ice lenses form and hence the hydraulic conductivity increases. In contrast, application of overburden pressure inhibits the formation of ice lenses and reduces the size of the cracks remaining when lenses thaw. As a result, the hydraulic conductivity is reduced. Key words : compacted clay, hydraulic conductivity, clay liners, soil liners, freeze-thaw, ice lenses, structure.

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