How to Select Suitable Geotextiles

How to Select Suitable Geotextiles

1. Step 1: Clarify the function of the geotextile (function first)

①Filtration (most common)Retain soil while allowing water to pass through, preventing soil loss and ensuring drainage. 

Recommended: PET staple fiber needle-punched geotextile. For water conservancy projects, river slope protection, drainage boards.

Not recommended: PP slit-film woven geotextile, small pores, easy clogging, poor filtration performance.

②SeparationSeparate different fill materials (soft soil and crushed stone, subgrade soil and bedding layer) to avoid material mixing. 

Recommended: Filament nonwoven geotextile. For expressways, high-speed railways, storage yards.

③Reinforcement / Load-bearingHigh tensile strength to disperse loads.

Recommended: Woven geotextile. For land reclamation, tailings ponds,  temporary heavy-duty roads; when high tensile strength is required, choose geotextile-geogrid composite products.

④ProtectionProtect HDPE geomembrane from puncture by crushed stone. 

Recommended: Staple fiber nonwoven geotextile. For landfills, water tanks, commonly 200–400 g/㎡.

⑤DrainageUsed with drainage blind ditches and drainage boards. 

Recommended: Staple fiber nonwoven geotextile with high porosity and good water conductivity.

2. Step 2: Select raw material PET / PP according to engineering environment

PET (Polyester)

✅Advantages: Good anti-aging performance, low creep, stable long-term      strength, suitable for permanent projects (high-speed railways, expressways, dams, landfills). 

❌ Disadvantages: Easy to hydrolyze when immersed in strong      alkaline environments for a long time.

PP (Polypropylene)

✅Advantages: Acid and alkali resistant, hydrolysis resistant, lower cost. 

❌Disadvantages: Poor UV resistance, aging quickly under long-term sunlight      exposure; higher creep than PET.

3. Step 3: Select indicators according to working conditions (unit weight, tensile strength, O95, permeability coefficient)

①Unit weight: 100 g/㎡ ~ 800 g/㎡

Protection layer, general filtration: 100–200 g/㎡

Subgrade separation, conventional slope protection: 200–300 g/㎡

Landfill membrane protection, heavy-duty soft foundation:       300–500 g/㎡

High-tensile woven geotextile: Tensile strength is the key       index instead of weight.

②Apparent opening size O95: Prevent fine soil particles from losing out. Small aperture for fine-grained soil; larger aperture for coarse-grained soil.

③Permeability coefficient: Must be higher than that of the foundation soil to guarantee smooth drainage.

④Breaking strength, tearing strength: Choose high-strength filament geotextile for projects with backfill compaction, heavy construction machinery and heavy loads.

4. Step 4: Avoid risks under special working conditions

①Long-term exposed outdoors: Prefer PET with UV stabilizer; PP is not suitable for long-term sun exposure.

②Seawater, saline-alkali and chemical sewage sites: Prefer PP geotextile with good hydrolysis and salt resistance.

③High-speed railway subgrade and important permanent projects: Prefer filament spunbond needle-punched geotextile (GB/T17639) for low creep and excellent durability.

④Matched with HDPE geomembrane: Nonwoven geotextile as protection layer; hard woven fabric is forbidden to avoid puncturing the membrane.

⑤Working conditions with sharp crushed stones: Increase unit weight to prevent puncture damage.

⑥Short-term temporary works: Cost-effective staple fiber geotextile or PP woven fabric is acceptable.

5. Quick Selection Table