Geosynthetics are widely used in construction of landfills, serving the significant functions of environment protection and provision of the structure durability. A proper selection of geosynthetics is critically important to secure a landfill effective operation and mitigation of ecological risks. This article considers the main criteria of geosynthetics selection, their properties and applications.
Contents
Geosynthetics main types and functions
Geosynthetics selection criteria
Geosynthetics main types and functions
Geosynthetics are materials used to secure an engineering facility durability. They may be made of polymers, fiber glass or composite materials and are used in various construction areas including landfill construction.
Geomembranes are water impermeable barriers used to prevent the leachate migration from landfills to environment. The most commonly used are membranes of high-density polyethylene (HDPE) characterized by high chemical resistance and mechanical strength.
Geotextiles perform the functions of filtration, separation and protection. In landfills, they prevent inter-mixing of soil layers and protect the drainage elements from clogging and mechanical damage.
Geocomposites are a combination of several geosynthetics such as geomembranes and geotextiles that enables combining of their properties and performing of several functions at once i.e. waterproofing, drainage and protection.
Geosynthetics selection criteria
Selection of proper geosynthetics is particularly important to secure a landfill durability and stability.
Performance. While selecting geosynthetics, it is necessary to take into account their ability to maintain their properties over the whole service life of a landfill. Tensile strength, resistance to punctures and UV rays and chemical resistance to the leachate aggressive components are key parameters.
Operation conditions. Every landfill is unique, so geosynthetics selection should account for the local operational conditions. These include:
- Hydraulic conditions: ground water level, soil type, underground water-bearing level.
- Climate conditions: temperature oscillations, precipitation, wind impact.
- Mechanical loads: waste mass pressure, traffic and other dynamic loads.
Chemical resistance. A landfill leachate may contain various aggressive substances including organic and non-organic acids, alkali, heavy metals and organic contaminants. Geosynthetics, particularly geomembranes, must be resistant to such impacts losing none of their properties over decades of operation.
Durability. Geosynthetics durability is a key factor defining their selection. Resistance to UV rays, oxidation and biological factors are also essential factors. Modern geomembranes and geotextiles normally have a service life of over 50 years, which meets the landfill requirements.
Compatibility with other materials. Geosynthetics are often used in combination with each other, therefore it is important to consider their compatibility. For example, a geotextile must provide reliable protection of a geomembrane from mechanical damage without compromising its waterproofing properties.
Applications and examples
Waterproofing barriers. Geomembranes are used to provide the sealing layers in a landfill lower and upper parts. Minimal permeability and high chemical resistance are essential for the lower barrier, while the upper layer should allow no rainwater. There are Geospan M, Geospan GHT PP WA Type 2 and Geospan GT PP WA Type 3 in Geospan range to be used in drainage systems.
Drainage systems. Geocomposites and draining geosynthetics are used for the leachate removal and the ground water level control. It is important that they should have high permeability and durability. In this direction, Geospan 3DM has proven well.
Slope reinforcement. Geogrids and geotextile are used for slope reinforcement and erosion prevention. In such applications, special attention is paid to tensile strength and resistance to mechanical damage that Geospan GT PP and Geospan GC cope with at ease.
Conclusions
Geosynthetics selection for landfill use should be based on integral assessment of performance, operation conditions and durability. A thorough design with all these factors taken into account allows development of reliable and durable landfills with environmental impact minimized.
Geospan materials are effectively used in development of reliable and durable facilities including landfills. We specialize in cost effective solutions for transport, civil, agrarian and other construction with geosynthetics of our own production used. All the materials are made of primary polypropylene, and every batch is tested by a 3rd party laboratory.
Many years of our material use has shown Geospan as a reliable producer of geotextiles capable of providing a stable protection and durability of infrastructural projects.
