Intermittent freezing mode to reduce frost heave in freezing soils — experiments and mechanism analysis

Two types of freezing tests have been conducted on Xuzhou silty clay. The intermittent freezing test results show that the frost heave increases step by step after the initial freezing stage, and its total amount is only 48.8% that resulting from the continuous freezing test. A model describing the growth process of the active ice lens in saturated, rigid soils has been established, and the importance of the frozen fringe is investigated in the model. The growth processes of the final ice lenses in the two freezing tests have been used for laboratory validation of the model, and the calculated results are in general agreement with the experimental data. The mechanism of using an intermittent freezing mode to reduce frost heave has been revealed by analyzing the growth process of the final ice lens. We indicate that, during the noncooling stage, the backward movement of the freezing front, which causes the disappearance of the frozen fringe, stops the growth of the final ice lens. This effect results in a step-type frost heave curve in the intermittent freezing test and reduces the heave amount effectively. Finally, problems concerning the practical application of the intermittent freezing mode are discussed in a preliminary manner.