•A thermodynamic constitutive model is developed for geomaterials based on the tenet of particle reconstruction.•The concepts of particle entropy, particle temperature, migration coefficient and potential energy density function are introduced.•The proposed model is verified by saturated/unsaturated soils undergoing thermal loading. A thermo-hydro-mechanical constitutive model is developed for geomaterials based on the tenet of particle rearrangement in porous granular materials undergoing thermodynamic processes. In this model, the concepts of particle entropy, particle temperature, migration coefficient and potential energy density function are introduced. The effects of temperature and saturation variation on energy dissipation and the soil–water characteristic curve of the geomaterials are also considered. This model can accurately describe the irreversible consolidation of normally consolidated saturated soils induced by thermal loading and the aging effect induced by cyclic thermal loading, which is attributed to the irreversible rearrangement of solid particles in the soils. However, as the overconsolidation ratio increases, volumetric expansion will likely become reversible. In this case, temperature-induced elastic deformation of the solid particles is more dominant than particle rearrangement. The constitutive model can accurately describe the effects of static stress, suction and temperature on the consolidation of unsaturated soils. An increase in temperature can cause thermal contraction at low suction but thermal expansion at high suction and the physical mechanism is the same as that of the thermal consolidation of saturated soils.