Numerical Simulation Of Channel Frozen Based On Solar Radiation Research

China is a nation of water resources shortage, agricultural water used accounts for more than half of the country's total water consumption. Concrete lining of irrigation channels is a effective measure to improve the efficiency and water conservation , frost damage of concrete lining the channel is seriously ,becoming a bottleneck restricting water-saving projects in the seasonal frozen soil area in China.For damage of concrete lining channel, different models of solar radiation were used, the channel boundary conditions are obtained to simulate the freezing process; using orthogonal experimental design theory, latitude, elevation, wind speed, the absorption rate of solar radiation, channel slope gradient channel were analysed, the surface absorption sensitivity of solar radiation was obtained; the effectiveness of anti-frost of FRP canal was analyzed in the northern seasonally frozen ground region ; it was analysed that the mechanism against frost heave of polystyrene insulation plate and reasonable thickness of insulation board in different parts, the law of against frost heave of insulation board has been are given in different areas ,the method of determining the thickness of polystyrene foam insulation board was given. the main conclusions of full text as follows:(1)calculate the channel surface solar radiation with solar radiation model ASHRAE, overcome the shortcomings that intensity of solar radiation is difficult to obtain in most region, the theoretical model of solar radiation intensity can be extended to other areas, that is regional universal. Direct analysis can be done in theory, do not need to monitor in the channel builded, the frost heaving in the channel design can be analyzed. For the cloudy slope monitoring points 2 and sunny slope monitoring points 8, the temperature considered thermal radiation in agreement with the measured temperature ,but larger than the measured sinusoidal temperature numerically, the maximum difference was 3.5℃and 2.7℃; The variation of frost heave are accordance, the heave capacity with heat radiation is less than the heave capacity measured sinusoidal load, the maximum difference are 0.8mm and 0.82mm; the two frost heave law are accordance, the normal frost heave force considered thermal radiation is less than the frost heave force measured sinusoidal load , the biggest difference are 0.066Mp and 0.047Mp. The bias of two results is due to that the negative temperature of solar radiation is less than measured temperature, so the temperature field is greater than the measured sinusoidal temperature.(2)Considering a variety of factors that concrete lining channels absorb solar radiation, calculate solar radiation using Hottel solar radiation, orthogonal analysis theory was used to research sensitivity analysis of influencing factors. Through analysis of range, trend analysis and variance analysis, obtained the sensitivity that concrete lining channels absorb solar radiation: wind speed, concrete absorption of solar radiation, channel slope gradient, altitude, latitude. The results from the trend analysis shows that: as the latitude increases, the concrete lining canals absorption of solar radiation is decrease; as the elevation increases, the concrete lining canals absorption of solar radiation is increase; when the wind speed increases, the concrete lining canals absorption of solar radiation is decrease; as solar radiation absorption rate increase, the concrete lining canals absorption of solar radiation is increase; sunny slope coefficient is1:1 ,absorbed solar radiation is maximum, followed by the slope coefficient are 1:2,1:0.5. Through analysis, the solar radiation absorption rate of concrete have a greater impact for the concrete lining channels absorbing solar radiation, brushing the surface of concrete lining channels and try to smooth the surface of the concrete structure, can be reduced concrete solar radiation absorption rate, thereby reducing the absorption of solar radiation.(3)Numerical analysis of displacement field shows: FRP materials was used, due to the elastic modulus smaller than ordinary concrete, the lining thickness is less than concrete lining panels, so displacement is larger, but it does not affect the channel safe operation, and through release of deformation, can improve the lining plate stress state. Numerical results of the stress field shows: normal frost heave force is the law of upper large and lower small, tends to uniform on the channel bottom; shear force is the law of upper small and lower large, almost become zero on the channel bottom, by FRP protective structure materials , the normal frost heave force can be reduced to 51% ~ 74%, the shear frost heave force can be reduced to 34% ~ 46%.(4)The anti-frost effect of polystyrene insulation board is remarkable in frozen region, it can reaches right temperature to soil temperature, the freezing does not occur.ADINA finite element software can calculate the thickness of polystyrene insulation board of the concrete lining channels in different region, the base soil temperature increases with increasing insulation thickness, but the temperature increased rate is decrease with insulation thickness increases. Therefore, the thickness of insulation board should be obtained by calculating. According to the meteorological data in different areas, channels base soil and groundwater conditions, the finite element software ADINA can be used to obtain the base soil temperature distribution and reasonable thickness of polystyrene insulation board, give correction for the results of formula or specification, provide reference for resistant frost design of concrete lining channels in different areas.