Multi-scale analysis of mudstone freeze-thaw damage mechanism

Freeze-thaw (F-T) cycle-induced mechanical deterioration of mudstone layers in slopes is a critical challenge for the stability of slopes located in cold-regions open pit mines. Indoor F-T cycle experiments were initially conducted on mudstone samples obtained from the North Slope of the Fushun West Open Pit Mine. Furthermore, a constitutive model for F-T damage was developed using Weibull distribution fracture mechanics. After that, a Voronoi tessellation-generating program and a program for inserting cohesive elements between tessellations were developed to establish a multi-scale thermo-mechanical coupling analysis platform in ABAQUS software. Finally, the damage constitutive model was integrated into Voronoi tessellations to simulate the mineral matrix. The research findings revealed that F-T cycles induced substantial damage to mudstone. Moreover, with an increase in the number of F-T cycles, the damage factors associated with each parameter significantly increased. Multi-scale analysis results indicated that for higher numbers of F-T cycles, samples may not necessarily develop cracks along initial flaws, but could instead be cracked in the matrix phase due to F-T damage. The F-T cycle exhibited a destructive effect on the stability of slopes in cold regions. Therefore, it is essential to consider the effect of F-T damage in the stability analysis and protection design of open-pit mine slopes in cold regions.