Geotextiles in Civil Engineering: Characteristics & Functions

Geotextile walls are a newly emerging field in civil engineering.

The rapid growth has been linked to its global adoption and wide range of uses.

In this article, we focus on geotextile walls, their characteristics, and their functions.

What is Geotextile?

Modern geotextiles are ideal materials that play a significant role in modern pavement design and maintenance techniques.

Geotextiles are expected to be resistant to organic and inorganic substances, which cater to a range of functions such as support, separation, and drainage.

From roads to harbours, dams to railways, buildings to bridges, embankments to coastal engineering projects, geotextile installation is widely used in civil engineering projects.

It is forecasted that geotextiles will have the highest growth rate among other areas of technical textiles.

Characteristics and Properties of Geotextiles

1. Physical properties:

thickness
specific gravity
weight
density
stiffness

2. Mechanical properties:

tenacity
tensile strength
flexibility
bursting strength
drapability
frictional resistance
compatibility
tearing strength

3. Hydraulic properties:

permeability
porosity
permittivity
turbidity /soil retention
transitivity
filtration length etc.

4. Degradation properties:

photodegradation
chemical degradation
biodegradation
hydrolytic degradation
mechanical degradation
other degradation occurring due to attack of termites, rodents, etc.

5. Endurance properties:

abrasion resistance
elongation
clogging length and flow, etc.

Types/Classification of Geotextile

Geotextiles are classified into two types. They are:

a) Based on Manufacture
b) Based on the Time of Use

a) Classification of Geotextiles Based on Manufacture

Based on manufacture, geotextile installation can be classified as follows:

Woven Geotextiles
Woven geotextiles are manufactured with the interlacement of two sets of yarns at 90 degrees in the weaving process. These geotextiles have high strengths and low elongations at rupture.

Nonwoven Geotextiles
Nonwoven geotextiles are made from staple fibres or continuous filaments. They are thicker than woven and are produced using the following bonding techniques:

Needle punching
Thermal bonding
Chemical bonding

Knitted Geotextiles
As the name implies, knitted geotextiles are manufactured with the interloping of one or more yarns in the knitting process. These geotextiles have low strength but are highly extensible.

Stitch-bonded Geotextiles:
These geotextiles are manufactured by interlocking yarns or fibres or both, bonded by sewing or stitching. Stitch-bonded geotextiles are strong, heavyweight, and can be produced rapidly.

Geocomposites
Geocomposites are made from a combination of two or more geosynthetic materials such as geogrids, geocells, geofoam, etc.

Geonets
Geonets are open grid-like materials formed by intersecting two sets of coarse, parallel, extruded polymeric strands at a constant acute angle. They are used to carry relatively large fluid or gas flows.

Geogrids
Geogrids are materials that have an open grid-like appearance and are popularly used in the reinforcement of soil.

Geomembranes
Geomembranes are continuous flexible sheets produced from one or more synthetic materials. They are used as vapour barriers and liners for fluid or gas containment thanks to their impermeable features.

Geocells
Geocells are relatively thick 3-dimension networks constructed from strips of polymeric sheet. The strips are bonded together to form interconnected cells that are filled with soil and concrete.

Geofoam
Geofoam slabs or blocks are a low-density network of closed, gas-filled cells created by the expansion of polystyrene.

GCLs
GCLs are geo-composite bottom geotextile layers bonded to a geomembrane that is prefabricated with a bentonite clay layer.

Geopipes
These are perforated or solid-wall polymeric pipes used for draining gases or liquids.

b) According to Time of Use

1^st Generation
These comprise geotextiles that are manufactured for other purposes, such as industrial sacking or carpet, but later used for geotechnical purposes.

2^nd Generation
These are geotextiles that were manufactured for certain geotechnical purposes. Unfortunately, the second generation of geotextiles did not adopt modern technology.

3^rd Generation
This era of geotextile was manufactured, designed, and produced to meet certain end-use. This is the geotextile we are talking about.

Functions of Geotextiles

Geotextile walls are used for numerous functions depending on the application. Here are thirteen functions of geosynthetics.

Separation
Sealing
Reinforcement
Filtration
Ponds
Protection
Drainage
Road Works
Railway Works
Sports field construction
Pipelines
Embankments
Agriculture

Conclusion

Geotextile walls play a huge role in civil engineering and other infrastructural work.

They are effective tools that have multifunctional characteristics that can help civil engineers solve a myriad of geotechnical problems.

Are you a civil engineer?

Get in touch with our consultants to learn more about geotextile installation and what it can help achieve in your civil engineering projects.