Controlling mechanism and quantitative characterization of thermal-hydraulic coupling properties of moraine soil containing frozen inclusions

The thermal-hydraulic coupling processes in moraine soils containing frozen inclusions are prevalent in cold alpine regions (for example, the Tibetan Plateau) and closely linked to various mountainous geological hazards. Despite extensive research, characterizing this coupling process remains challenging. This study investigates the evolution of the thermal-hydraulic properties of moraine soils containing frozen inclusions under warm water flow, considering key parameters and phase change. Parameter values were calibrated using field and laboratory data. The simulation results show the monotonic trend of outlet temperature, ice content and permeability. Thermal conductivity, soil porosity, fluid temperature, frozen inclusion content, and initial matrix permeability play predominant roles in the evolution process. Based on these findings, comprehensive models to quantitatively characterize the seepage evolution process were developed and discriminant models for two equilibrium states were established, incorporating critical factors. Furthermore, an in-depth discussion on the simulation of the phase-change process and the selection of the relative permeability range was provided. The findings enhance our understanding of thermal-hydraulic coupling processes in moraine soils and offer a valuable reference framework for future studies in this field.