Exploring the Inter-Relationship between Climatic Conditions and Heat-Water Transfer in Deformable Cracked Surface Strata

Climate-induced soil desiccation and cracking present escalating challenges to infrastructure stability, necessitating comprehensive investigations of soil-climate interactions. Hence, this study presents a thermo-hydro-mechanical (THM) modeling framework to investigate the response of desiccation-cracked soil to climatic variations. The model was constructed using field observations and statistical analysis and incorporated three years of meteorological data from a susceptible area in Iran. The analysis explored heat conduction, water advection, mechanical deformation, and crack evolution under prolonged environmental conditions. Results revealed that heat flux was highly dependent on temperature gradients and crack geometry. Heat migrates upward from the subsurface when air temperature is lower than soil temperature or during rainfall, conditions typically associated with wet or cold seasons, whereas during warmer periods heat is transferred into the soil. Water flux exhibited strong seasonal variability, with rainfall-driven infiltration through the surface and enhanced evaporation near cracks during dry periods. During rainfall, water flow velocity in soil pores was at least 50 times higher than during warm weather. Moreover, a direct relationship between volumetric strain, temperature, and relative humidity was identified. Crack deformation intensified, and long-term climatic exposure resulted in cumulative shrinkage, increasing on average from 12.5% in the first year to 17.5% in the third year.