ZHANG C, TANG J, LIU Y F，et al．Study on macro-mechanical damage and microstructural effects of tailings under freeze-thaw cycles［J］.Journal of Henan Polytechnic University( Natural Science) ，doi:10.16186/j.cnki.1673-9787. 2025030063

doi: doi:10.16186/j.cnki.1673-9787.2023050063

Received：2025-03-28

Revised：2025-05-19

Online：2025-06-05

Study on macro-mechanical damage and microstructural effects of tailings under freeze-thaw cycles

Zhang Chao^1,3, Tang Jie^1,2,3, Liu Yongfeng^4,5, Ma Changkun³, Chen Qinglin^1,2, Zeng Peng^1,2

（1. School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China；2. Jiangxi Provincial Key Laboratory of Safe and Efficient Mining of Rare Metal Resource, Ganzhou 341000, Jiangxi, Chian；3. State Key Laboratory of Geomechanics and Geotechnical Engineering Safety, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, Hubei China；4. School of Resources and Safety Engineering, Chongqing University, Chongqing 400044, China；5. Shenzhen Zhongjin Lingnan Non-ferrous metal Company Limited, Shenzhen 518024, China）

Abstract: [Objective] Freeze-thaw cycles significantly affect the structural stability of tailings dams in permafrost regions. This study aims to reveal the macro-micro damage mechanisms of tailings materials under freeze-thaw cycling. [Methods] Through triaxial consolidated undrained shear tests, scanning electron microscopy (SEM), and micro-CT scanning, the effects of freeze-thaw cycle frequency on the mechanical properties and microstructural evolution of tailings were investigated. A correlation mechanism between macroscopic mechanical damage and microstructural changes was established. [Results] The results indicate that freeze-thaw cycles significantly degrade the macroscopic mechanical properties of tailings. The peak shear strength decreased by 13.35% after one freeze-thaw cycle. During the 5–10 cycle stage, the peak strength reduction rate was 8.8%, while the reduction rate decreased to 3.9% in the 10~15 cycle stage. After 15 cycles, cohesion and internal friction angle decreased by 50.9% and 59.3%, respectively. Freeze-thaw cycling caused particle edge abrasion and rounding, with the shape factor decreasing from 1.38 to 1.34. The pore fractal dimension increased from 1.55 to 1.64, porosity rose from 8.9% to 16.91%, and the proportion of connected pores surged from 4.68% to 15.51%, The study further reveals a nonlinear negative correlation between porosity and shear strength, while the internal friction angle exhibits an exponential growth trend with increasing particle shape factor. [Conclusion] The research results can provide a reference for the stability analysis and disaster prevention of tailings dams in permafrost regions.

Key words: tailings; freeze-thaw cycles; mechanical damage; microstructure; macro-micro correlation

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