Generally speaking, separated geotextile does not have the effect of anti-seepage, the main indicators for performance appraisal is permeability coefficient. Coefficient of ordionary geotextile is higher than ordinary plain soil, around 0.01-0.001.But geotextile ,when combined with rubber, asphalt, and plastic will form a waterproof complex and effect of anti-seepage will increase 10 times, and a combination with asphalt, and rubber will form waterproof roll like SBS; a combination with plastics, generally polyethylene, polyvinyl chloride, EVA (official name is geomembrane) will form anti-seepage geomembrane or composite geomembrane, because white composite geotextile outside is for the protection, so the project is also called anti-seepage geotextile. Therefore, there is not much difference between the two, just different statement.
The geomembraneis is impermeable material made of plastic film as anti-seepage material, and composites with non woven fabric. Its anti-seepage property mainly depends on the anti-seepage property of plastic film. At present, the domestic and foreign anti-seepage plastic films mainly include polyvinyl chloride (PVC) and polyethylene (PE) and EVA (ethylene / vinyl acetate copolymer), design of the tunnel also used ECB (blending geomembrane of ethylene-acetic acid-ethylene modified asphalt), which is a kind of macromolecular chemistry of flexible material, and it features a smaller proportion, good extensibility, high adaptation to the deformation, corrosion resistance, low temperature resistance, and good frost resistance. The geotextileis a permeable composite material made of synthetic fibers, which are made by needling or knitting; its physical structure is multi-layer cloth membrane. Finished products are cloth-shaped, the general width is 4-6 meters, length is 50-100 meters. The geotextile is divided into woven geotextile and non-woven geotextile. The geotextile has the characteristics of excellent filtration, drainage, isolation, reinforcement and protection, with light weight, high tensile strength, good permeability, high temperature resistance, freezing resistance, aging resistance and corrosion resistance.
