Concrete Lining Canals Are Available At Different Water Depths And Freeze-thaw Performance Deterioration And Destruction Characteristics Under Conditions

As one of the indispensable resources for the survival of human society,water is also the basic need for the sustainable development of human society.Especially in the lack of water resources in northwest China,agricultural production and irrigation water rely heavily on the water transfer supply of the transmission and distribution canal network,and the method of concrete lining on the surface of the canal solves the problem of low canal water transmission coefficient caused by the leakage of soil canal beds.Due to its own strength and durability,concrete has also become the main material for seepage prevention of lining canals,and is widely used in northern irrigation areas.However,the elastic and brittle material characteristics of concrete lining make it deteriorating material properties and cracking of the lining structure under the influence of factors such as the increase of water transmission years and the freezethaw cycle caused by the climatic environment.In this paper,the mechanical properties of the U-shaped concrete lining canal gradually deteriorate with the increase of water transport age,and the cracking eventually leads to the failure of the impermeable layer.Combined with the changes of water pressure of lining canals caused by different water depths and the influence of different freeze-thaw times on the properties of concrete materials,the deterioration test of mechanical properties of lining materials was carried out.The combination of test and numerical simulation was used to further explore the influence of water depth and freeze-thaw times on concrete lining canals,summarize the deterioration law of lining materials and the failure characteristics of lining structures,and conclude the following:(1)According to the analysis of the mechanical properties test of concrete materials,the water depth factor and freeze-thaw number factors have adverse effects on the microstructure and mechanical properties of concrete,and the results of variance analysis show that the water depth factor and the freezethaw number factor have a significant impact on the deterioration of concrete materials 0.95 or more;(2)The numerical model of D 80 U-shaped concrete lining canal is calculated and compared with the actual lining failure characteristics to simulate the failure characteristics and The failure characteristics of the actual lining are basically consistent,and the results of extrusion deformation displacement by frost heave force are basically consistent with the existing measured and other research results The distribution law of the principal stress and the location of crack cracking are in good agreement with the existing research results,and the feasibility of numerical simulation is verified.(3)Through numerical simulation analysis,cracking simulation analysis was carried out by establishing lining canal models with different canal depths,and the results showed that different types of U With the gradual deterioration of the concrete lining canal,the failure characteristics of the concrete lining canal also change significantly.With the increase of freeze-thaw times,the tension crack began to extend to the bottom of the canal from the combination of the straight slope section and the arc section of the shady slope,and a dense penetration crack was formed at the bottom of the canal,and the tension crack began to expand to the bottom of the canal from a small number of cracks at the junction of the straight slope section and the arc section of the Yang slope,and formed a crack with a density lower than that of the bottom of the shady slope canal.(4)Under the action of frost heave force of different types of U-shaped concrete lining canals,the concrete lining canals generally showed the extrusion inclination deformation on the inside of the canal,and gradually increased the deformation displacement along the height direction,reaching a maximum value at the top of the canal,and the deformation displacement of the shady slope was greater than the deformation displacement of the Yang slope,and the bottom of the canal was the smallest With the continuous increase of freeze-thaw times and water depth,the displacement of the same position of the same U-shaped concrete lining canal is also gradually increasing,and with the increase of canal depth,the displacement of the corresponding position of the U-shaped concrete lining canal is also increasing,but the overall deformation displacement law remains unchanged.(5)The stress distribution of different types of U-shaped concrete lining canals is generally manifested as the stress concentrated at the junction of the straight slope section and the arc section of the shady slope and thus moving to the bottom of the canal,and the same is true for the sunny slope.With the continuous increase of freeze-thaw times and water depth,the stress at the corresponding position of the same U-shaped lining canal is increasing,and the stress of different U-lining canals increases with the increase of arc radius,and the position of stress distribution is basically the same as the position of crack distribution.(6)The frost heave force of different types of U-shaped concrete lining canals when initial cracks and cracks penetrate gradually decreases with the increase of freeze-thaw times and water depth,and the freeze-thaw number has a greater influence on the frost heave resistance performance of concrete lining canals than the influence of water depth factors.There was a good correlation between water depth,freeze-thaw times and frost-heave force,and the fitting degree was above 0.92.