The anti-seepage lining of channel can reduce the seepage loss of water, improve the ability of channel water transportation and shorten the water delivery time, etc. It can also play the role of anti-erosion, anti-siltation, anti-collapse and stable canal bed to ensure the safety of water conveyance and enhance the modernization of irrigation area And so on. According to the type of material used, the lining can be divided into three types: rigid, flexible and rigid-flexible. Rigid lining materials are cast-in-place or precast concrete slab and masonry, flexible materials are plastic film, composite geomembrane and asphalt linoleum.
Channel composite lining is laying a layer of flexible membrane under the rigid concrete slab. At present, the flexible film material is generally a plastic film or a geomembrane, which is waterproof and water-proof under normal temperature conditions. The laying of flexible membrane under the concrete slab in the short term to reduce the leakage of channels to improve the effective utilization coefficient of canal water is effective, but to frost heave only played some indirect and minor role.