Two-dimensional Frost Heave Test Of Trapezoidal Channel Matrix Soil

In winter,the channels in north of China suffers the damage of the concrete lining slab due to frost heaving of the soil,which leads to seepage and seriously decreases water transportation efficiency.Moreover,it affects stability of channel slop.The service life of the channel lining is also shorten due to the frost heaving and damage of the base soil,which makes the management and maintenance work difficult.Reconstruction and maintenance cost a lot of manpower and financial resources.How to prevent frost heaving damage of channel linings and continuously increase the utilization rate of farmland water resources has become an urgent problem in agricultural production in the north irrigation area.Practice shows that to solve the problem of frost heaving damage in channels,the factors that affect the soil frost heaving of the channel base need to be studied first,and the relationship between the influence factors and the frost heaving stress need to be investigated.Based on the results of one-way frost heaving test of the existing channel base soil,test on the two-dimensional frost heaving of channel base soil is particularly important.On the basis of summarizing previous research results,the two-dimensional frost heaving of the trapezoidal channel base soil was analyzed based on the basic theories of permafrost physics,frozen soil mechanics,thermodynamic field coupling theory and other related disciplines.The main work is as follows:The test model was designed according to similarity criterion,and a two-dimensional frost heaving test self-reaction device for the trapezoidal channel base soil was made according to the model size.The silt clay was selected as the sample for the two-dimensional frost heaving test of the trapezoidal channel base soil.The soil sample was remolded conform to the standard test method.The single factor test was conducted with the factors of the initial water content,average frost-heaving temperature and prestress,which affect the two-dimensional frost heaving of the trapezoidal channel base soil.The test results show that the frost heaving stress has a positive correlation with the water content,and it has a quadratic relationship with the temperature and the prestress.The orthogonal test with three factors and three levels was designed and carried out with the factors of the initial water content,average frost-heaving temperature and prestress.The most unfavorable influence factor combination of frost heaving stress and the top and the lope in the two-dimensional base soil is obtained.And the results of the significant analysis of the influence of the influencing factors on the frost heave stress at the slope and the top were given.Based on the isotropic constitutive model of frozen soil,ANSYS software was used tosimulate the two-dimensional frost heaving of trapezoidal channel base soil by thermal mechanical coupling,and the finite element simulation was verified by the test results.The work of this paper provides basic material for further research on the trapezoidal channel base soil.