Mitigating frost damage in cold region canals: performance evaluation of a two-layer geomembrane lining structure

To address frost damage to canal lining structures in arid and cold regions, this study proposes the use of a two-layer composite geomembranes (TLCGs) as a frost-heaving composite lining structure. To assess the performance of the two-layer geomembrane lining structure (TLCGLS), field tests were conducted. Considering the interaction between TLCGs and lining structure and canal foundation soil, a calculation model of canal frost heave is established based on the water-heat-force coupling theory of foundation soil. The stress of canal lining with single-layer composite geomembrane (SLCG), frictionless two-layer composite geomembranes (FTLCGS), and TLCGs under frost-heaving conditions is analyzed. The results indicate that TLCGLS can enhance the temperature of canal foundation soil by 7 % and decrease the water content by 12 %, thereby effectively mitigating canal deformation by 38 %. The TLCGs cushion under the canal lining can effectively release the tangential freezing constraint, so that the lining structure has certain flexibility, so as to prevent frost damage. Therefore, the reasonable use of TLCGs with appropriate friction and the setting of flexible structural joints can prevent frost damage.