INFLUENCES OF TEMPERATURE AMPLITUDES AND TIME INTERVALS ON FROST HEAVE

In this paper,frost heave tests using frost susceptible silty clay were carried out by 1-D frost heaving test system with different temperature amplitudes and time intervals in continuous-intermittent freezing mode.Freezing front,frost heave and temperature gradient were analyzed when frost depth reached in stable stage.The influences of temperature amplitudes and time intervals on frost heave were acquaired.The results show that,in different temperature amplitudes,the curves of freezing front and frost heave fluctuate periodically and the period is 240 min which is equal to time intervals.Frost heave is 3.38 mm and 2.55 mm in different temperature amplitudes.With the increase of temperature amplitudes,frost heave reduce 23.2% and 42.0% respectively than that in continuous freezing mode.In different time intervals,frost heave increase in the parabolic,step and broken line type.Frost heave is 2.82 mm,2.55 mm and 1.81 mm when time intervals are 2 h,4 h and 8 h respectively.It is clear that frost heave reduces with the increase of time intervals.However,if time intervals are longer than 8 h,segregation ice and frost heave decrease.In that case,the strength of frozen wall will decrease in artificial freezing project.