Geosynthetic Clay Liner
GCLs have gained recent popularity as substitutes for or augmentations to compacted clay liners in landfill cover systems. They are also used as composite bottom liners or in single liner applications in canals, dams and ponds.
They are factory manufactured and typically needle punched and/or stitch bonded with chemical or mechanical adhesives. Once hydrated, they form an effective hydraulic barrier against liquids.
Durability
The durability of Geosynthetic clay liner is a vital factor in the success of any landfill liner system. These materials are designed with UV stabilizers to protect them from degradation caused by prolonged exposure to sunlight. The liners are also constructed with puncture resistance to minimize the likelihood of leaks and failure. Additionally, these liners are prefabricated to save time and money during installation. They are easy to deploy by unrolling and overlapping, reducing labor costs and logistics.
These liners are manufactured by needle punching or stitch bonding a high-quality sodium bentonite clay powder between layers of geotextiles. They are then subjected to controlled heat treatment to thermally lock the layers and Geosynthetic clay liner fibers in place. This creates a highly durable liner with excellent shear strength. These prefabricated liners are often used to replace compacted clay in landfills, surface impoundments, and secondary containment applications.
GCLs offer many advantages over traditional compacted clay liners, including lower hydraulic conductivity, water-swelling properties, and self-healing capabilities. They are resistant to varying weather conditions and are less likely to be affected by freeze-thaw or desiccation-rewetting cycles, which can cause cracking in compacted clay liners.
The durability of GCLs can be augmented by overlaying them with a geomembrane, creating a composite liner. This combination of materials is useful for landfills, because it allows them to reduce leachate and gas migration rates.
Strength
GCLs are a popular choice for landfill, waste containment, and water protection applications. They are especially effective as a hydraulic barrier in landfill caps and base liner applications, canals, and dams. They also are less costly than a traditional clay liner and take up less space. Additionally, they can withstand installation and settlement stresses without significantly impacting their hydraulic performance.
A geosynthetic clay liner is a flexible, porous liner made of a thick layer of sodium bentonite clay bonded to a non-woven or woven geotextile, which makes it very strong and durable. It is also very easy to install. The GCL can be installed in a single pass over a slope, which means that it is a cost-effective and environmentally friendly alternative to soil barriers.
Landfills require a containment solution to avert solid and liquid garbage waste from polluting the surrounding groundwater and environment. A typical containment solution involves a liner-sand final cover system that complies with standard federal design standards. The Gabion GCL is one of the most economical and efficient ways to achieve this compliance.
GCLs are manufactured by needle punching or stitch bonding bentonite clay powder between layers of a woven or non-woven geotextile. The stitched or needle punched GCL is then heat-treated to improve shear and confinement strength. Some GCLs are coated with a polyethylene, which improves their longevity and resistance to chemical attack.
Stability
Over the past decade, geosynthetic clay liners (GCL) have gained widespread popularity as a substitute for or an augmentation to compacted clay liners in landfill cover systems and composite bottom liners. This popularity has led to intensive research into the GCL’s hydraulic and diffusion properties, chemical compatibility, mechanical behavior and durability. This paper presents a review of the most important aspects of this research and discusses design implications for systems that utilize GCLs.
Geosynthetic clay liners are high-performance environmental liners consisting of two needle punched geotextile layers encapsulating a layer of sodium bentonite for sealing. The bentonite swells when it comes into contact with water, creating a low-permeability barrier that is effective in preventing seepage. They also offer resistance to physical and chemical break down in harsh environments, such as landfills.
GCLs have been used successfully in many applications, including waste containment and landfill capping closures. However, they should not be seen as a panacea for all landfill contamination problems. In fact, a few case histories reported in the present paper highlight that geosynthetic clay liner technology should be evaluated on a site-specific basis and not as a replacement for conventional bottom-liner-sand final covers. Therefore, it is crucial to carefully evaluate the barriers to water, leachate and gas migration in a given landfill application before choosing a liner material.
Cost
A geosynthetic clay liner (GCL) is a manufactured lining that is essentially two needle punched geotextile layers encapsulating a layer of sodium bentonite for sealing applications. The liner is then stitched or bonded together to create a durable composite with high shear strength and low permeability. This liner is used in landfills and other containment systems to provide a hydraulic barrier to water, leachate, or other liquids and gases. It is often used as a replacement for compacted clay liners or geomembranes.
The GCL is also resistant to varying weather conditions and can be installed in cold, inclement environments. In addition, it is not affected by freeze-thaw or desiccation-rewetting cycles that can cause deterioration of a compacted clay liner. This is particularly important for a landfill application because the liner is designed to hold waste in place and protect groundwater and the environment.
GCLs also have a self-healing attribute that can seal around objects or punctures. This is because they are made from a combination of needle-punched, woven and non-woven geotextiles that are sandwiched together with the bentonite. This self-healing property helps reduce leakage and eliminates the need for costly repairs.
Another benefit of the GCL is that it can be easily cut to the size required for installation, which saves on labour and material costs. It is also easier to install than a conventional compacted clay liner. It is also more economical and uses fewer natural resources, as one truckload of GCL can replace 150 truckloads of compacted clay.