Investigation of crack propagation and acoustic emission characteristics in jointed rock under freeze–thaw cycles based on DEM

• Freeze–thaw expansion force from water–ice phase transition is the primary driver of freeze–thaw damage in jointed rocks. • Microcrack initiation and propagation, matrix particle detachment, and clay mineral loosening transform rock from dense to porous, degrading mechanical properties. • Increasing freeze–thaw cycles significantly reduce uniaxial compressive strength and deformation modulus, shifting failure from brittle to brittle-plastic or plastic. • DEM-based numerical model effectively captures microcrack evolution and acoustic emission characteristics in jointed rocks under freeze–thaw cycles.