Deterioration Law of Mechanical Properties of Sandstone in Cold-Regions Under Freeze-Thaw and Simulation Analysis
To investigate the deterioration law of rock mechanical properties under freeze-thaw,triaxial compression tests and numerical simulation experiments were conducted on sandstone specimens in cold-regions subjected to different times of freeze-thaw cycle.The results show that the increase of freeze-thaw cycles and confining pressure leads to the transformation of rock failure from brittleness to ductility.When the times of freeze-thaw cycle increased from 0 to 40,the peak cohesion of the rock decreased by 21.9%,the internal friction angle decreased by 14.7%,and the elastic modulus decreased by more than 50%.During 0 time of freeze-thaw cycle,the peak total energy at 12 MPa confining pressure increased by 670.8%compared with that at 0 MPa confining pressure,the elastic energy increased by 420.5%,and the dissipation energy increased by 2 356.6%.During 40 times of freeze-thaw cycle,the peak total energy at 12 MPa confining pressure increased by 1 030.9%compared to that at 0 MPa confining pressure,the elastic energy increased by 603.9%,and the dissipation energy increased by 4 153.9%.The total number of cracks,tensile cracks,and shear cracks under different confining pressures all exhibited an S-shaped growth pattern with the increase of axial strain,with shear cracks dominating in the early loading stage and tensile cracks appearing during the plastic stage.The research findings can provide valuable guidance for understanding the deterioration mechanism of rock mechanical properties in cold-regions and analyzing deformation and failure.