Geosynthetics

Geosynthetics are synthetic products used to stabilize terrain, they are typically polymeric products that are used to solve civil engineering problems, it consists of eight main product categories, i.e. geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geofoam, geocells, and geocomposites.

It manufactured from the polymeric material used with soil, rock, earth, or other geotechnical engineering-related material as an integral part of a man-made project, structure, or system.

The polymer nature of the products makes them suitable for use in the ground where a high degree of durability is required.

Types of geosynthetics:

These geosynthetics are further described in brief as follows:

1.Geotextiles:

A continuous sheets of woven, non-woven, knitted or stitch-bonded fibres or yarns are generally termed as a geotextile.

These sheets are versatile and permeable have an appearance of the material.

The applying of geotextile is for separation, filtration, drainage, reinforcement and erosion control.

2.Geogrids:

Geosynthetic materials have an open grid-like appearance.

These can be rigid or flexible polymer grid-like sheets with large apertures.

The main application is to strengthen volatile soil and waste mass.

3.Geonets/Geospacers:

They are formed by successive extrusion of parallel sets of polymeric ribs at acute angles from each other.

It consist of three-dimensional networks of rigid polymer or rigid polymer fibers, rigid polymer fibers in different configurations.

The design function is entirely within the drainage where they were given which are used to convey all types of fluids.

Advantages of geosynthetics:

• Geosynthetic sheets consume less space and can fit anywhere in a landfill.
• Geosynthetic materials are homogeneous because they are manufactured in a workshop with quality control.
• It improves the soil properties as compared to conventional materials.
• These geosynthetic materials are less expensive to purchase, transport, and install as compared to aggregates and soils.
• Geosynthetic materials are exceptional for achieving high-performance rates and superiority in work.

Disadvantages of geosynthetics:

1. Handling, storage, and installation must be taken with quality control and quality assurance.
2. Clogging of geotextile, garnets, geo pipes and geo-composites is a challenging design for some soil abnormal conditions.
3. For any geosynthetic material, long-term performance should be assured using appropriate additives including antioxidants, UV screeners, and filters.

Functions of geosynthetics:

Following are different functions of geosynthetics and further can be explained as follows:

1.Separation:

Geosynthetic serves to separate two layers of soil that have different particle size distributions.

In this section, three specific areas can be monitored as follows:

• Separators in railway applications.
• Separators in highway applications.
• Safety material for geomembranes.

2.Filtration:

A geotextile provides filtration function that serves in the same aspect as the formation of gradations of aggregates.

The main purpose of filtration is to retain filtered soil particles and allow water to pass through the geotextile.

To fulfil this function the geotextile material must possess properties such as permeability and retention.

Geotextiles like woven and non-woven are appropriate to carry out such filtration.

3.Barrier:

Some geosynthetics can be used as a relatively impermeable barrier, this prevents liquid and gases from being mixed between the two layers of soil.

Geomembrane act as good inhibitors because their permeability is very low.

The most common application of this function is in pavement overlays.

4.Drainage:

Some geosynthetics can also act as a drain that can establish the flow of any fluid through a low permeable soil.

Geotextiles like non-woven can act as good drainage & geocomposite can be used for high flows.

Good drainage is an important factor to avoid track faults.

5.Protection:

Geosynthetics can protect for friction and perforation.

During construction, the geotextile can act as a cushion above the geomembrane, it prevents or minimizes any kind of damage to the ground floor layer.

Uses of geosynthetics:

In pavements:

Geotextiles are used as a filter to limit the motion of soil particles as water flows into the drain structure.

Geotextile is used because of its high permeability and high survival so that an initial shape can be maintained under the loading criteria.

Nonwoven geotextile is preferred to perform a filtration function.

Due to dynamic loading, the water leaking into the road avoids contamination of the drainage base by geotextile which reduces the mechanical properties of the base.

In foundation:

Geosynthetics solutions for foundations of reinforcement include the use of biaxial-geogrids such as tentex and strata grids combined with geotextiles to allow for the reduction of stone required to reinforce foundations.

This reduces material movements.

Geosynthetics provide complementary technical recommendations detailing the type of geogrid and textiles needed to build a stable and secure foundation.

In Railroad applications:

A separate layer is provided for imposition of ballast fines and migration of ballast to the subgrade.

To achieve strength and lower elongation woven geotextiles are used compared to non-woven geotextiles.

Also read: Admixture, Composite materials & Superplasticizer

Conclusion:

Geosynthetics have at least one component constructed from a synthetic or natural polymer in the form of a sheet, a strip, or a three-dimensional structure.

These products are currently used in many geotechnical, transportation, hydraulic, and personal development applications including roads, airspace, embankments, etc.

They are a polymer product hence used to solve civil engineering issues.