Investigation on the frost heave-induced pressure and hydro-thermal processes in freezing soil under rigid constraint and hydraulic pressure

Abstract

Frost damage in engineering is closely related to hydraulic pressure in artificial freezing ground areas and cold regions; however, limited studies have focused on this relationship. To clarify the evolution of frost heave-induced pressure (FHIP) and its effect on engineering stability, unidirectional freezing tests are performed under rigid constraint and various hydraulic pressures. The results indicate that the development of the FHIP is induced by ice growth. Meanwhile, the FHIP increases with hydraulic pressure, which consequently increases the pore water pressure (PWP) at the base of the warmest ice lens. When the PWP on both sides of the frozen fringe reaches equilibrium, the water stops migrating, ice stops growing, and FHIP stops increasing. The frozen fringe is captured via X-ray computed tomography, and a model for calculating the maximum FHIP is developed based on the frozen fringe theory. The model is validated and compared with the experimental results. The increased FHIP prevents water migration in freezing soil by increasing the soil density and decreasing the segregation temperature of the frozen fringe. Additionally, the factors contributing to the increase in FHIP are discussed, and an application of this study to engineering design and maintenance in cold regions is proposed.