Analysis Of Soil Physical And Mechanical Parameters During Freezing

Soil in nature is a kind of composite material with complex physical and mechanical properties.The phase transformation of water in soil during freezing leads to great difference between the physical and mechanical properties of soil and the mechanical properties before phase transition.The frozen soil contains different soil particles,liquid water,ice,a variety of organic compounds,a little of gas and so on.Different material content,the existence of the state,the number of species involved will make the physical and mechanical properties of soil have great difference under different conditions.After the freezing process,the different materials in the soil will change or move,especially the transfer of liquid water and the formation of ice.In order to fully understand the changes of soil physical and mechanical properties in the freezing process,this paper will base on the theoretical calculation and analysis and laboratory tests of soil for further studies,and provide reliable reference for the study of physical and mechanical parameters of frozen soil.The conclusions are as follows:(1)Based on water migration during freezing,the elastic-plastic theory of the ideal material and the calculation theory of thick wall cylinder under the action of spatial symmetry,this paper concludes the formula of shear strength based on the law of Mohr-Coulomb of frozen soil under the low confining pressure.(2)During the freezing process,the variation of moisture in silty clay and mudstone samples increases with the decrease of temperature,the increase of dry density and moisture content.The change degree of the sample material changed significantly with the decrease of temperature and the increase of dry density and water content.(3)The change of the material properties of the sample determines the difference of the mechanical parameters of the soil.The cohesive of silty clay and mudstone is positively correlated with the decrease of temperature and the increase of dry density.When the temperature is high,the cohesion cuts down with the raise of water content,and the cohesion increases with the increase of water content during the reduce of temperature.But the internal friction angle generally has no regularity with temperature,dry density and water content.(4)During the freezing process,the change of moisture in the samples restricts the material properties and finally shows the diversity of the mechanical parameters.The relationship between soil shear strength envelope and mechanical indexes is discussed.