| Along with the development of economy, agricultural water use accounts for the proportion is gradually reduced. The contradiction between water supply and demand has become increasingly prominent. The development of water-saving agriculture is imperative. To enhance the utilization of irrigation water, China has constructed a lot of canal concrete lining. But in the seasonal frozen soil area of our country, because of low temperature in winter, canal soil frost heave deformation and concrete lining strength is not that high, is resulted in a lot of lining cracks, even destroyed. Therefore, study on the mechanism of frost heave and the failure process of canal lining is of great significance to prolong the life of canal lining.This paper studied the influence factors of frost heaving damage of concrete lining canal. There are four main factors, canal base soil, temperature, moisture condition and stress condition. The technical measures of anti-frost heaving of the canal is researched. Through the finite element modeling, numerical simulation is carried out using the ABAQUS software. The canal soil temperature field was analyzed. Using the temperature field as a predefined field, the example canal is analyzed considering the Goodman contact, the main conclusions are as follows:(1) The natural weather conditions of solar radiation, ambient temperature, wind speed, and many factors are simplified as a combination of the second and third temperature boundary conditions. The finite element model of canal soil temperature field is establishe using ABAQUS software. The numerical calculation of boundary temperature of canal soil is carried out. Through comparing with the analytical solutions, the results showed that the established numerical model is correct and feasible. The canal soil temperature field was simulated, and the simulation are divided into consideration of water phase change and without considering the water phase change. By comparing the two analysis, we come to a conclusion that the canal soil temperature field considering the water phase change has a certain lag and is more in line with the actual situation.(2) The Goodman contact elements of zero thickness are set between the canal soil and concrete in creating the finite element model, which are used to simulate canal soil frost heaving deformation of concrete plate sliding and mutual extrusion. The normal frost heave force, tangential freezing stress are compared with the frost heave model without contact, we find that the maximum normal frost heaving force decreased by 30%, the maximum tangential freezing force decreased by 40% in the model with Goodman contact. Because the contact model can release energy in the deformation due to slip, the stress caused by the deformation is reduced.(3)The freezing force is zero at the distance of about 1/3 from the slope toe in the slope plate, and then it would increase to both sides, forming the weakest points, with the normal frost heave force participation. The result can well explain the mechamism why in the point of 1/3 from the slope toe always appears cracks.(4)The frost heave displacement in the center of canal bottom is bigger than that in other points in the canal bottom, while the freezing force here is zero, which result in suspending the concrete plate of canal bottom, making this point be the most vulnerable part of the canal bottom. The result can well explain the reason why the center of the canal bottom often appears cracks. |
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