Study on the Mechanism of Freeze–Thaw Cycling Effects on Soil Aggregate Stability and Pore Structure Evolution

Against the backdrop of global warming, changes in the frequency and intensity of freeze–thaw cycles in cold regions profoundly impact soil physical structure. This review examines the mechanisms by which freeze–thaw cycles influence soil aggregate stability and pore structure evolution, focusing on revealing their synergistic evolution patterns. Results indicate that ice crystal growth during freeze–thaw processes directly disrupts soil cementation systems through expansion pressure and wedging effects, leading to aggregate disintegration and pore restructuring. This process is not unidirectional but forms a coupled feedback cycle of “ice crystal action–aggregate disintegration–pore restructuring.” Aggregate stability governs the initial pore restructuring, while the pore structure, in turn, influences aggregate stability by regulating water migration and colloidal dynamics. Responses of soil aggregates and pore structures to freeze–thaw cycles are comprehensively regulated by multiple factors, including soil physicochemical properties, freeze–thaw parameters, and anthropogenic disturbances. This synergistic evolution mechanism profoundly impacts soil water and heat transport, nutrient cycling, and erosion resistance. The paper also identifies current research gaps in regional coverage, cross-scale coupling, and in situ monitoring techniques. It envisions future efforts integrating multi-scale observations with intelligent technologies to deepen understanding of freeze–thaw-driven soil structure evolution mechanisms, thereby providing theoretical support for sustainable agriculture and ecological conservation in cold regions.