Analysis of damage evolution and study on mesoscopic damage constitutive model of granite under freeze–thaw cycling

The failure of rocks in seasonal frozen areas under freeze–thaw cycles (FTCs) is a frequently problem in engineering construction, posing a huge threat to the stability of the engineering. In order to explore the mechanism of rock damage degradation. It is necessary to analyze the damage evolution process of rocks and establish an accurate FTCs rock damage constitutive model. Taking the granite in the seasonal frozen zone of Northeast China as the research object, the macro and meso parameters and microstructure of the FTCs granite were analyzed through indoor tests. A new method is proposed to define damage variables considering mesoscopic parameters to establish a mesoscopic damage constitutive model for rocks, further revealing the damage mechanism and failure law of rocks under freeze–thaw load coupling. The research results indicate that in the early stage of FTCs, 20 cycles contribute significantly to the damage and deterioration of rocks, accounting for about 50