A study on the physical index change and triaxial compression test of intact hard rock subjected to freeze-thaw cycles

For a long time, experimental studies on frost weathering of rock has been concentrated on soft rock to medium-hardness rock, and research on intact hard rock is relatively less common. Combined with specific engineering projects, taking fine sandstone (UCS = 114.8 Mpa) and coarse sandstone (UCS = 104.1 Mpa) as representatives for intact hard rock, the physical parameters and the triaxial compression mechanical characteristics subjected to different freeze-thaw cycles are studied in this paper. The results show that under freeze-thaw cycling, the intact hard rock still has obvious attenuation. The porosity of the two sandstones increases, and there is a good linear fit with the freeze-thaw cycles. Under the same confining pressure, the triaxial compressive strength of the two sandstones decreases with an increase in freeze-thaw cycles, and an exponential decay relation is expressed. The friction angle φremains constant, and there is a good exponential decay relationship between the cohesive force C and the freeze-thaw cycles. The related conclusions can provide some references for hard rock engineering.