An energy based constitutive model of water-saturated frozen rock

To study the effects of cold region climatic characteristics and excavation disturbance on the mechanical properties of rocks, a constitutive model was established. Dynamic compression test were conducted on red sandstone using a split Hopkinson pressure bar (SHPB) to investigate the combined effects of freezing temperature and impact pressure. The results show that the stress-strain curve of the specimen did not exhibit a compaction stage, and the elastic deformation stage was very small, accounting for approximately 2.1% of the total stress-strain curve. The dynamic compressive strength increased as the freezing temperature decreased, and there was a strain-rate enhancement effect. The energy absorbency rate (η) increased with the decrease in freezing temperature, and it remained constant at around 40%, unaffected by changes in impact pressure. At high freezing temperatures and low impact pressures, the degree of fragmentation decreased, and the fractal dimension reduced. From a micromechanical perspective, the action mechanisms of freezing temperature and impact pressure on the rock were explained. A dynamic constitutive model for saturated frozen red sandstone was established based on energy theory, and compared with experimental results. This research provides theoretical guidance for the study of rock properties and engineering construction in cold regions.