Nonzero angle between the directions of matric suction and gravity during horizontal freezing

The main reason why horizontal freezing is different from vertical freezing is that the nonzero angle between the directions of matric suction and gravity changes dynamically. Current theories are mainly applicable to vertical freezing, but the interactions between driving force components during horizontal freezing are ignored. Based on soil water potential theory, the driving force of water migration in unsaturated silt during horizontal freezing is further investigated. First, the influence of different components of soil water potential on water migration is analysed, and the nonnegligibility of gravity in unsaturated silt is confirmed. Then, an experimental test is conducted to explore the particularity of horizontal freezing, and equations for calculating the nonzero angle are derived. Finally, the evolution of the nonzero angle during horizontal freezing and the influence of different factors are summarized based on theoretical analysis and numerical calculation.