Creep Characteristics and Damage Constitutive Model of White Sandstone Under Short-Term Freeze-Thaw Cycles

Rock masses in short-term freeze-thaw zones tend to fail under long-term loading. Therefore, investigating the creep damage characteristics of rocks under short-term freeze-thaw cycles is of great significance for the stability evaluation of rock engineering. In this study, white sandstone was used as the research material. Multi-gradient short-term freeze-thaw cycle tests and graded loading creep acoustic emission (AE) tests were performed to investigate the creep behavior and AE response characteristics of sandstone after short-term freeze-thaw action, and a creep damage constitutive model was established. The results show the following: (1) The mass loss rate, P-wave velocity reduction rate, and porosity growth rate of sandstone increase with increasing freeze-thaw cycles and duration. (2) The instantaneous axial strain of specimens increases with the stress level under different freeze-thaw durations and cycle numbers. (3) The cumulative AE event rate decreases significantly with increasing freeze-thaw cycles and duration. (4) Based on the seven-element viscoelastic model, a creep damage constitutive model was developed by introducing the freeze-thaw damage factor (D), with an average goodness-of-fit of 0.964. The findings can provide a theoretical reference for the long-term stability assessment and disaster early warning of geotechnical engineering in short-term freeze-thaw regions.