Research On The Horizontal Frost Heaving Force Distribution Mode And Factors Of Cantilever Pile In Overwintering Foundation Pit

In winter cold area of foundation pit engineering need to consider the effect of frost heave of soil.When the frost heave has a large level of frost heave force,the horizontal deformation of the supporting structure will be increased,cracks or partial shear cut,which will cause serious pit to collapse,direct threat to the safety of pit.In this paper,the cantilever pile support structure is selected as the research object,and the distribution pattern of horizontal frost heave force and its influencing factors are studied based on FLAC3 D numerical simulation software.The distribution model of horizontal frost heaving force: horizontal frost heave force along the pile length appears up and down small,middle large parabolic distribution.In the depth range of 1/3 ~ 2/3 pit,the maximum force value is reached,and the maximum value is about ten times of the initial earth pressure.The influencing factors:(1)The lower the negative temperature is,the larger the frost heave force is,parabola distribution pattern.The maximum displacement of the pile top,the maximum displacement of the pile top and the maximum horizontal frost heave force are linear at different temperatures.(2)Impact of soil: coarse sand,clay,silty clay and silt soil maximum freezing heave force has great difference,and its strength values followed by coarse sand <clay <silty clay <silt,excavation range,the horizontal frost heave force produced by the coarse sand is increased first,and then the stable trend is maintained.The silty,silty clay and clay are first small,after then larger and smaller,parabolic distribution.(3)Effect of soil density: with the increase of density,the frost heaving force increased,the maximum frost heaving force and corresponding soil density was a quadratic function.(4)Impact of water content: after more than a certain value,the soil produces frost heaving force,and thefrost heaving force increases with the increase of water content,the maximum frost heaving force and water content appears power function.(5)Effect of support pile stiffness: with the increase of pile stiffness,the restraining effect of the soil is obviously enhanced,the horizontal displacement of pile top is decreasing,but the horizontal frost heave force is increasing.(6)Effect of excavation depth: the horizontal frost heaving force is quite different in different excavation depth of the foundation pit,the deeper of depth,the greater the value,the two shows the role of second function.