On the Dynamic Mechanical Behaviors of a Fault Unwelded Bimrock Exposed to Freeze-Thaw-Fatigue Loads: A Lab-Scale Testing

• Published in: Geofluids Vol. 2022; pp. 1 - 15
• Main Authors: Wang, Yu, Wang, Hongjian, Tao, Sun, Yi, Xuefeng
• Format: Journal Article
• Language: English
• Published: Chichester Hindawi 30.03.2022; John Wiley & Sons, Inc; Hindawi Limited; Hindawi-Wiley
• Subjects: Axial strain; Coupling; Cracking (corrosion); Cracking (fracturing); Cycles; Cyclic loads; Damage; Deformation; Evolution; Experiments; Failure modes; Fatigue tests; Fracture mechanics; Freeze thaw cycles; Freeze-thaw durability; Freeze-thawing; Laboratories; Loads (forces); Materials fatigue; Mechanical properties; Mining; Mining engineering; Rocks; Soil; Soil investigations; Soil particles; Soils; Testing
• ISSN: 1468-8115; 1468-8123
• DOI: 10.1155/2022/7851201

This work is aimed at investigating the mechanical behaviors of a fault unwelded bimrock subjected to coupled freeze-thaw (FT) and fatigue loads. The influence of FT cycle on rock strength, deformation, damage evolution, and failure morphology was detailed investigated. The testing results show that the soil-rock interface is sensitive to freeze-thaw condition. Interface damage and cracking contribute a lot to sample strength, volumetric deformation, and damage evolution. In addition, a sudden increase of stress amplitude results in the increase of damage, afterwards, the coupling degree of bimrock improves with the increase of loading cycles. A coupling freeze-thaw and mechanical damage evolution model was proposed using the damage index defined by ultrasonic velocity and axial strain. It is found that the evolution trend of the model is strongly related to the previous freeze-thaw damage. Moreover, failure mode of bimrock changes from shear failure to bulging failure with increasing FT cycles. The failure process of bimrock is the rearrangement of the fine soil particles and rock blocks, the soil matrix and rock block bear axial cyclic loads by their interactions.