1. Definition and raw materials
Filament geotextile is a fabric made of polymer slices through spinning, laying nets, needle punching reinforcement and other processes. It can also be called polyester filament needle punched non-woven geotextile. It is an environmentally friendly building material that does not contain chemical additives and is not heat-treated.

2. Main characteristics
High strength: Under the same gram weight specifications, the tensile strength of filament geotextile in all directions is higher than that of other needle punched non-woven fabrics.
High temperature resistance: filament geotextile can withstand temperatures up to 230°C, and still maintains structural integrity and original physical properties even at high temperatures.
Good permeability: Due to its thickness and needle punching forming characteristics, filament geotextile has good plane drainage and vertical permeability, which can be maintained even after many years.
Creep resistance: Compared with other geotextiles, filament geotextile has better creep resistance, which makes it have better long-term effectiveness.
Corrosion resistance: Filament geotextile can resist the erosion of common chemicals in the soil and the corrosion of gasoline, diesel, etc.
Ductility: Under a certain stress, filament geotextile has good elongation, which enables it to adapt to the unevenness of irregular base surfaces.

3. Application fields
Filament geotextile has good mechanical properties, water permeability, corrosion resistance and anti-aging ability, and is widely used in civil engineering and environmental protection engineering, mainly including:

Water conservancy projects: Filament geotextile can be used for anti-seepage, embankment reinforcement, river management, reservoir construction, etc. in water conservancy projects.
Road engineering: Filament geotextile can be used for reinforcement, waterproofing, anti-corrosion, isolation layer, etc. in road engineering.
Railway engineering: Filament geotextile can be used for reinforcement, isolation, anti-seepage, anti-corrosion, etc. in railway engineering.
Environmental engineering: Filament geotextile can be used for soil stabilization, landfill coverage, yard coverage, etc. in environmental engineering.
Mining Engineering: Filament geotextile can be used for mine waste treatment, slope reinforcement, anti-seepage, etc. in mining engineering.
Governance Engineering: Filament geotextile can be used for river regulation, soil erosion control, wind and sand fixation, etc. in governance engineering.

4. Functions and Roles
It plays a permanent isolation role, has frost resistance and the bearing requirements required for construction.
Water can penetrate in all directions without accumulating pressure, while preventing soil loss, which is beneficial to stability and anti-corrosion performance.
Due to the fluffiness of its structure, it can effectively control the drainage of the surface of geotechnical engineering.
Due to its good puncture resistance, elongation and fluffiness, it can effectively protect the waterproof layer from potential mechanical damage.
Fluffiness and high strength improve the overall stability of the project and increase its strength.

5. Standards and Parameters
The production and application of filament geotextiles need to follow certain standards, such as the national standard GB/T 17639-1998 (now updated to GB/T 17639-2023). Its technical parameters include unit area mass deviation, thickness, width deviation, breaking strength, breaking elongation, CBR bursting strength, equivalent pore size, vertical permeability coefficient, tearing strength, etc.