Typically manufactured with polypropylene or polyester, geotextiles are used to protect, drain, filter, separate or reinforce soil. These permeable fabrics are available in three forms, which include:
- Heat bonded – These look like ironed felt.
- Woven – These look like mail bag sacking.
- Needle punched – These look like felt.
Geotextiles have become popular in geotechnical designs and environmental engineering due to their various benefits such as preventing soil erosion. Various applications of geotextiles include geomats, geogrids, geotextile tubes, geonets and geosynthetic clay liners. Some product examples can be found at Macaaferri (https://www.maccaferri.com/my/products/geotextile-mactex/) who supply a range of MacTex® geotextiles for different applications, which will help you to understand the product. If you want to know more about how they’re used and why they’re essential, read on.
The following are 6 uses of geotextiles which makes them essential for geotechnical designs and environmental engineering applications.
Seepage forces can cause drainage or displacement of soil particles. Therefore, an industrially graded filter is used to prevent soil erosion and soil particle displacement. The pores of the filter should be small enough to prevent movement of even the smallest soil particles during drainage. If small particles move into the filter, it can become blocked which could affect drainage.
Geotextiles are used as an alternative material for:
- Separating stone aggregates from the natural soil sub-grade
- Proof water for prevention of cracks in concrete pavements
2. Soil Reinforcement
Effective soil tension and compression is required for preventing erosion and increasing soil capacity for re-cultivation. If the soil’s tension and compression is poor, it may not carry even regular loads. Soil is reinforced using geotextile – it is commonly placed between natural sub-grade and stone aggregates.
Geotextiles help increase soil separation from stone aggregates and reinforce it to bear maximum traffic load.
Geotextiles can be used to reinforce embankments and retaining walls by stabilizing them. After installation, the front face of the wall needs to be protected with gunite or shot crete. For higher pressure, gunite or shot crete can be mixed with additives and adhesives for reinforcing earth walls.
3. Filtration and Drainage
Geotextiles are widely used to enhance the soil’s natural filtration and drainage capacity to prevent erosion which may occur due to flowing water such as rivers, rainfall and floods. By separating soil particles from soil subgrade and maintaining proper soil moisture, geotextiles ensure minimal erosion. They are also useful for retaining the soil’s nutrient capacity for re-cultivation.
In transmission, geotextiles allow gases and liquids to flow along the plane of the fabric as opposed to through the fabric. Hence, water enters and travels within the fabric to reach a specific location.
5. Erosion Control
Erosion control is the widest application of geotextiles. For geotextiles allow gases and liquids to flow along the plane of the fabric, geotextiles are not only used for traditional cultivation such as riverside and irrigation, but these are also used in sports complexes, industrial land, corporate areas, home gardens, etc.
For erosion control, geotextiles are used for the following applications.
- Diversion ditches
- Slope protection
- Culvert outlets
- Scour protection
- Stream and canal banks
In this context, geotextiles are used as geocomposites. These are prefabricated vertical drains installed to enhance the soft compressible layers of soil. Conventional sand drains have become obsolete with the use of geo composites as these are easier to handle and install. Above all, geo composites are less expensive than conventional sand drainage enhancement systems, which is why they are commonly used in land cultivation.
6. Soil Stabilisation
The texture and mineral density of soil changes overtime, especially when it is exposed to heavy pressure, such as the pressure caused by traffic. When concrete constructions are made atop the soil, the sub base soil becomes weak, leading to easy flow of minerals into the aggregate soil base. This not only leads to poor quality of soil, but also makes the construction on soil vulnerable to cracks and damage.
Geotextiles are thus useful for stabilizing soil and increasing the load bearing capacity of weak soil. They are also used to reduce the quantity of material required to enhance the sub-base. Geotextiles effectively separates aggregate soil base from the sub-base, which is necessary for increasing the stability of any construction on the soil. Geotextiles can also prevent sub-grade particles from traveling into the aggregate base.
Geotextiles are the future of soil protection and erosion prevention. These are already used for agricultural applications to meet the increasing global demand for food crops.