The Experimental Technique For Studying The Soil Deformation In The Freezing-thawing Cycles And The Freezing Induced Deformation Feature Of Clay

Seasonal frozen soils are widely distributed in China and have caused many kinds of disease in the construction of subgrade and foundation. Frost heave and thaw settlement is one of the most common diseases. There are still lack of mature experimental technique and widely-accepted deformation model for the frost heave and thaw settlement problem. This research focuses on the experimental technique and deformation mechanisms of frozen soil. One-dimensional freezing-thawing test and three-dimensional freezing-thawing test were carried to study the variation of soil’s volume and its influencing factor.In this research, new experiment methods, including one-dimensional freezing technique and three-dimensional freezing technique were first built up, as well as their devices. Then the freezing and thawing process of four kinds of soil were studied using these techniques. The influences of water content, soil density and salt content are considered in these tests.The experimental results show that both volumetric shrinkage and expansion may present in the freezing process. A possible reason is owing to the combined action of the expansion of ice crystal and the construction induced by the crystallization force and capillary force. Further, a theoretical model was proposed and used to predict soil volume change induced by freezing.