The Analysis Of Canal Frost Heaving Damage Chain Model And Chain-Cutting In Cold Area

The frost heaving damage is one of the main disasters in frozen regions.Most of the regions in China are in the higher latitudes,and 75% of the land area is permafrost and seasonally frozen soil.With the change of seasons,day and night alternate,under the temperature difference in the positive and negative effect the rock and soil produce frost heave and thaw settlement.And under these two effects,the internal structure of the rock and soil changes,which affects the physical and mechanical properties.Rock and soil produce frost heaving and thaw settlement caused by the frequent occurrence of canal engineering damage in the northern region of China.Therefore,frost heaving damage is in urgent need to resolve the problem of canal construction project.According to the process of canal frost heaving disaster formation conditions and damage are deeply discussed.Based on the analysis of water conditions,soil conditions and temperature conditions of the canal frost heaving disaster,according to the universality principle of disaster chain theory and chain disaster theory,this paper makes a detailed analysis and discussion on the mechanism of the canal frost heaving,which shows that the formation and development of the canal lining structure frost heaving damage have the chain regularity.In this paper,the theoretical analysis,the frost heaving test and numerical simulation of the prototype canal are taken as the main research methods,and the factors causing the frost heave of the canal are comprehensively analyzed,to provide the theory and basis for the design and construction of canal engineering in cold area.The main research contents and main conclusions in this paper are as follows:(1)According to the universal principle of catastrophic chain theory,based on chain disaster theory,the water condition,soil condition and temperature condition of canal frost heaving disaster are analyzed,and the chain failure model of canal frost heaving is established.(2)Through field test of frost heaving damage analysis of canal,observation of air temperature and soil temperature,soil moisture,soil,deep freeze,frost heave stress,deformation and other factors,analysis of the canal frost heaving damage of the chain rule.The result shows that as the air temperature decreases,the soil temperature continues to decrease,the moisture content of canal foundation soil changes at different parts of the canal,and the moisture content of canal foundation soil increases at 60 cm depth range from the ground surface,and presents a frozen frontal surface.The freezing period,the minimum temperature of shady slope is-25 ℃,corresponding to the maximum freezing depth is 146.2 cm and frost heave stress is 178 kPa;the minimum temperature of sunny slope is-21 ℃,corresponding to the maximum freezing depth is 123.5 cm,frost heave stress is 154 kPa;the minimum temperature of canal bottom is-23 ℃,corresponding to the maximum freezing depth is 147.2 cm and the frost heave stress is 163 kPa.(3)Through numerical simulation,analysis of the destruction process of frost heaving,and the changes of stress and strain field distribution of soil temperature field based canal.With the increase of the soil depth of the canal foundation,the temperature gradient decreases gradually,and the nearer the temperature contour to the bottom,the closer to the horizontal straight line.Simulation of the maximum frozen depth in different parts of the canal are respectively 139.8 cm,141.3 canal bottom slope cm,slope 122.4 cm,the maximum heave deformation is 11.89 cm,occurred in the bottom of canal.The canal lining surface stress concentrated region,located in the middle part of the canal bottom plate and canal slope lining board surface and slope plate close to the toe position.(4)Study on the chain relationship of canal frost heaving,based on the observation data of field prototype test and the results of the past canal frost heaving test,the model of frost heaving of chain cutting disaster mitigation is established,and reasonable measures for preventing and reducing frost heaving of canal are put forward.