Mechanical Response and Macro–Micro Damage Mechanisms of Sandstone Under Low‐Frequency Cyclic Disturbance After Freeze–Thaw Cycling

Freeze–thaw cycling and cyclic disturbance jointly affect rock stability in cold‐region mines, yet their influence on sandstone damage evolution remains insufficiently understood. Sandstone from the Dasuji Molybdenum Mine underwent 0, 10, 20, 30, and 40 freeze–thaw cycles, followed by uniaxial compression and cyclic disturbance tests at 5 Hz. Acoustic emission (AE), RA‐AF analysis, X‐ray diffraction, and scanning electron microscopy characterized damage evolution and cracking behavior. Freeze–thaw cycling progressively reduced both peak strength and elastic modulus. Cyclic disturbance promoted propagation and coalescence of existing defects. Recorded peak AE energy and ringing counts generally declined, while the proportion of shear‐classified AE events increased from 31.2% to 53.6%. Major mineral composition remained largely unchanged, whereas pore expansion, intergranular debonding, and fracture development indicated progressive microstructural deterioration. These results provide experimental insights into sandstone damage evolution relevant to slope stability assessment in cold‐region mines.