Research On Frost Heave Of Canal With Solar Radiation In Arid Cold Area

China is facing a severe shortage of water resources. Per capita water is less than aquarter of the world’s average level. Agricultural water use accounts for70%of national totalwater consumption. Irrigation water utilization rate is only30%~40%. Loss of water isextremely alarming. The contradiction between supply and demand of agricultural water ismore and more serious. In north area the seasonal frozen lining canals are seriously damagedby frost heave. Frost heaving damage is the most important reason for the irrigation waterresources waste. Frost heaving damage shortened the project life, reduced seepage effect,resulted in an increase in irrigation maintenance and management costs. Those direct impacton the hydraulic efficiency of the play, which restricts the healthy development ofanti-seepage project.As we all know, the key factors cause frost heaving destruction are soil, moisture,temperature and external loads, etc. This paper started from the temperature factor as aresearch starting point. First studied the freeze-thaw period canal temperature changes andestablished trapezoidal canal surface solar radiation calculation method. Solar radiationdifferences different canals slope were analyzed. With the results of solar radiation, theinversion method and numerical simulation methods were used to obtain canal temperaturedistribution and changes. Finally, under the influence of solar radiation analysis consideringasymmetric section lining channel frost resistance effect and a reasonable angle. Mainconclusions gained can be expressed as follow:(1) Hottel solar radiation model, which has a simple form, the advantages of fewerparameters to be determined, considered the type of climate, altitude and other factors posters,was more suitable in our channel temperature field calculation using. Calculations of shady,sunny and channel bottom solar radiation on the selected trapezoidal canal showed that solarradiation received of parts is significant different. In most of the freezing period, shady slopecannot receive the direct radiation, the radiation intensity is low, less energy is received.Despite the shady shelter effect, sunny slope is always able to receive direct radiation,maximum angle between light and slope angle is about80°, the radiation intensity of larger. The average exposure time is about650h on sunny slope,110h only on shady slope. Sunnyslope received total radiation is about three times the shady slope.(2) In the freezing period in Jing Hui Gansu Province, shady and sunny surfacetemperature differences are significant on east-west irrigation canals, shady temperature isalways lower than the sunny one. Freezing period is longer than the sunny slope, soil freezingearly in the sunny slope of about10d, melts lag approximately10d. Overall temperaturedistribution appears as uneven and asymmetry. Shady frozen depth is larger than the sunnyslope. Maximum frost depth is about40%of the shady slope.(3) With the results of solar radiation, the inversion method and numerical simulationmethods were used to obtain canal temperature distribution. Numerical simulation method ismore complex, but more comprehensive considerations, closer to the real situation, the resultsare more accurate. Lining surface and air temperature trend is basically the same, but itsslower heating, cooling faster, lining maximum surface temperature below the ambienttemperature. The maximum temperature diff on shady and sunny slope in14:00or so, about5℃. In the daytime, when the lining surface began to accept after about1hour of solarradiation, the temperature began to rise significantly, sunny surface solar radiation intensitygreater warming faster, steeper temperature.(4) Based on the analysis of results of asymmetrical cross-section canals numericalsimulation,50°is the most reasonable slope angle. Asymmetrical trapezoidal cross-sectionchannels sunny heaving increased only about1%, shady frost heaving reduced by about2%,frost heave deformation standard deviation of0.31, less than0.37symmetrical cross-sectionchannels, thus asymmetric cross channels more uniform distribution of frost heave andanti-frost better. Frost heaving force of asymmetrical section canal smaller increase, morereasonable, more uniform distribution of the amount of frost heave and anti-frost effect, butalso to reduce construction costs, reduce channel on land resources occupied.