FROST HEAVING AND THE CLASSIFICATION OF SOILS IN ACCORDANCE WITH THEIR FROST SUSCEPTIBILITY

Problems of soil freezing were studied with particular reference to the heaving of frost susceptible soils, and the results obtained were used to establish a soil classification system based on frost susceptibility. The physical mechanism of freezing of fine soils is considered, and mathematical studies are outlined of the segregation of ice in the form of lenses, and the periodicity of these lenses. The interpretation of the results of experiments on soil freezing have been directed towards a verification of the theoretical results. Experimentation is described in which artifical soils consisting of mixtures of pure powered silica and mineral tale were used, and the notion of critical rate of propagation is discussed. The slope of the graph of frost heaving in relation to the square root of the freezing index expresses the relative frost susceptibility of the soil. Details are given of the experimental method of soil classification, which is based on the systematic measurement of the frost heaving of soil samples of the same dimensions and fed with water under the same conditions and subjected to the same process of one-dimensional freezing. The studies indicate that the heaving of a soil that is free to deform is a linear to the surface. It was also found that heaving occurs only when the rate of advance of the frost front falls below a certain value called the critical rate.