Functions of geotextiles 1.Separation The isolation of the railway dregs and the roadbed, roadbed and the soft base, surface of the airdrome and parking lot and the groundsill, different dam materials. It isolates the soil and the gravel of two kinds different Granule pathway from the groundsill or other buildings. 2.Reinforcement 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 earthbody stability. 3.Protection It prevents the bank from being washed out, protects the bank and the Bottom, prevents the water and soil from being washed away