Application of geotextiles
Filtration
The filtration layer of the dykes, river canal, seacoast, concrete slope, retaining walls. At the same time of preventing the clay granule from passing, it allows the water and the gas pass through freely.
Separation
The isolation of the railway dregs and the roadbed, roadbed and the soft bas , surface of the airdrome and parking lot and the groundsill, different dam materials. It isolate the soil and the gravel of two kinds different granule pathway from the groundsill or other buildings. 
Adding muscle
The highway, railway, soil-stone dam, breakwater, airport, backfill soil of retaining wall, slope protection, etc in which distributes the earth stress, prevents the side-displacement of the earth body and improves the earth body stability.
Protection 
It prevents the bank from being washed out, protects the bank and the bottom, prevents the water and soil from being washed away.