Laboratory Studies on the Influence of Freezing Methodology on the Shear Strength Behavior of Artificially Frozen Clays

Abstract

It is essential and important for artificial ground freezing (AGF) engineering design and maintenance to systematically investigate the mechanical properties of artificially frozen soil. Based on a series of low-temperature triaxial shear tests, the mechanical properties of artificially frozen clays under different freezing methodologies (including freezing mode, freezing temperature, and confining pressure) were investigated and compared in this study. Importantly, the commonly used mechanical parameters of artificially frozen soil do not consider the effect of pressure during freezing, and the results presented that the stress–strain and shear strength behaviors of the artificially frozen clay freezing under pressure were better than those bearing freezing without pressure. In addition, both the lower freezing temperature and the higher confining pressure could lead to a notable improvement in the shear strength behavior of the artificially frozen clay. Furthermore, the significance of freezing factors was analyzed and revealed in this study, and the results demonstrated that the mechanical properties of the artificially frozen clay were more sensitive to the changes in freezing temperature, while the higher confining pressure would weaken the influence of the freezing temperature on mechanical properties. This could motivate, considering the effect of freezing conditions, especially the pressure during freezing, the development of a more practical design in AGF engineering.