Abstract: In view of the problems that the engineering rock mass in cold regions is often subjected to freeze-thaw erosion,
the freeze-thaw cycle test and Brazilian splitting test were carried out on the granite with natural cemented joints. Combined
with optical microscopy,digital speckle (DIC),three-dimensional surface topography scanning,SEM and other technologies,
the physical characteristics,tensile mechanical characteristics and failure mode evolution after freeze-thaw cycles were explored.
The test results show that after 60 freeze-thaw cycles,the porosity of granite with natural cemented joints increases by
17. 91%,the wave velocity decreases by 8. 28%,and the average growth width of cracks reaches 3~8 μm. With the increase of
the number of freeze-thaw cycles,the micro-cracks of the sample gradually increase and form holes with the increase of the pore
size. After 60 freeze-thaw cycles,the tensile strength of the cemented joint decreases by 32. 23%,and the peak strain increases
by 18. 41% . Through DIC technology,three-dimensional morphology scanning and SEM analysis,it is found that the cemented
joint shows a mode of expanding from the center of the joint to both ends in the Brazilian splitting test. The sharpness of the cemented
joint failure surface decreases significantly with the increase of the number of freeze-thaw cycles,and the overall morphology
tends to be homogeneous and smooth,reflecting the obvious freeze-thaw cycle effect.