Woven vs. Nonwoven Geotextiles: Choosing the Right Fabric for Your Project

By Luke McIntosh, P.E., Partner, Civil Engineer

Geotextiles are permeable fabrics used in civil engineering and construction projects to enhance soil stability, provide filtration, separation, and drainage. These versatile materials can be broadly categorized into two main types: woven and nonwoven. Understanding the differences between them is crucial for selecting the optimal fabric for your specific application.

Woven Geotextiles

Woven geotextiles are created by interlacing two or more sets of yarns or filaments, similar to how traditional textiles are made. This manufacturing process results in a strong, dimensionally stable fabric with defined pore sizes.

Woven Geotextiles

• Key Characteristics:

• High tensile strength: Woven geotextiles generally offer higher tensile strength compared to nonwoven options, making them suitable for applications requiring significant reinforcement.

• High load capacity: Their interlocked structure allows them to effectively distribute loads.

• Lower permeability: The defined pore sizes can result in lower permeability compared to nonwoven geotextiles.

• Good filtration in specific particle sizes: The consistent pore structure allows for predictable filtration of certain soil particle sizes.

• Common Applications:

• Soil reinforcement in retaining walls and slopes

• Erosion control in high-energy environments

• Base reinforcement under roads and railways

• Construction of embankments over soft soils

Nonwoven Geotextiles

Nonwoven geotextiles are manufactured by bonding or interlocking fibers through mechanical, thermal, or chemical processes. This creates a fabric with a random fiber orientation and a more complex pore structure.

Non-Woven Geotextiles

• Key Characteristics:

• High permeability: The interconnected pore structure allows for excellent water flow.

• Superior filtration: The tortuous path created by the random fibers effectively traps a wider range of soil particles.

• Good separation: They prevent the intermixing of different soil layers.

• Cushioning and protection: The thicker, more flexible structure can provide cushioning and protection to underlying layers.

• Lower tensile strength (generally): While advancements have led to stronger nonwoven options, they typically have lower tensile strength than woven geotextiles.

• Common Applications:

• Filtration behind retaining walls and under drains

• Separation layers between different soil types or between soil and aggregate

• Drainage layers in landfills and sports fields

• Erosion control in lower-energy environments

• Protection layers for geomembranes

Choosing the Right Fabric

The selection between woven and nonwoven geotextiles depends heavily on the specific requirements of your project. Consider the following factors:

• Strength requirements: If high tensile strength and load-bearing capacity are critical, woven geotextiles are often the preferred choice.

• Filtration needs: For applications requiring efficient filtration of a wide range of soil particles, nonwoven geotextiles are generally more suitable.

• Permeability requirements: If rapid water flow is necessary, nonwoven geotextiles offer higher permeability.

• Separation needs: Both types can provide separation, but nonwoven geotextiles excel at preventing the intermixing of fine and coarse materials.

• Cost considerations: The cost of each type can vary depending on the specific properties and quantity required.

Conclusion

Both woven and nonwoven geotextiles are valuable tools in modern construction and geotechnical engineering. By understanding their distinct characteristics and application areas, engineers and contractors can make informed decisions to ensure the long-term performance and stability of their projects. At Davidson A+E, we rely on collaboration with our geotechnical engineering counterparts to identify the best product given the specific application on the project site, combined with material properties of the soils to be encountered, the project budget, etc. to provide long term value on the client’s significant investment.