Effect of water distribution patterns on the activation energy of unsaturated soils during phase transformation

Abstract

Abstract Unsaturated soils in vadose zones often experience periodic phase changes during seasonal temperature fluctuations. The liquid in partially saturated soils significantly affects the physical and chemical processes associated with the phase transformations. This study examined the role of water distribution patterns on the activation energy of unsaturated soils. The results revealed that the homogeneously mixed and evaporation‐driven specimens exhibited higher activation energy than the horizontally layered specimen, which exhibited the lowest activation energy. In addition, the activation energy results indicated that the induction time, increased with an increase in the water saturation, requires a longer induction time and results in a more significant difference in the final products, such as elastic wave velocities, during the freezing process. In addition, the activation energy and soil stiffness results revealed that the homogeneous system required a higher activation energy than the heterogeneous system. The higher heterogeneity degree of the vertically and horizontally layered water specimens delayed the primary water‐to‐ice phase change. This study recognizes the significance of heterogeneity in activation energy for phase transformation in unsaturated particulate media.