Composite geotextile is a kind of geotextile composed of woven fabric and non-woven geotextile. It has the functions of filtration, isolation, reinforcement and protection.

A. Filter function: it can be used as the filter layer of dike, river channel, coast, concrete slope, sunken river bottom, retaining wall, etc. it can prevent soil particles from passing through, and allow water or gas to pass through freely.

B. Isolation function: it can be used to isolate railway ballast from subgrade, subgrade and soft foundation, surface layer and foundation of airport and parking lot, and different dam building materials, so as to separate two kinds of soil sand and stone with different particle sizes from foundation or other buildings.

C. Reinforcement: used in highway, railway, earth rock dam, breakwater, airport, retaining wall backfill, slope and other projects to distribute soil stress, prevent soil lateral displacement and improve soil stability.

D. Protective function: it can prevent the erosion of wind, wave, tide and rain, and protect the bank and bottom to prevent soil erosion