ZHANG C, TANG J, LIU Y F,et al.Macromechanical damage and microstructural effects of tailings under freeze-thaw cycles[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(6):9-17.

doi:10.16186/j.cnki.1673-9787.2025030063

Received: 2025/03/28

Revised: 2025/05/19

Published: 2025/1014

Macromechanical damage and microstructural effects of tailings under freeze-thaw cycles

Zhang Chao1,2, Tang Jie1,2,3, Liu Yongfeng4,5, Ma Changkun2, Chen Qinglin1,3, Zeng Peng1,3

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

Abstract: Objectives 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 Freeze-thaw cycles significantly degraded 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 in the 10~15 cycle stage， the reduction rate decreased to 3.9%. 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 increased markedly from 4.68% to 15.51%. Furthermore， porosity exhibited a nonlinear negative correlation with shear strength， while the internal friction angle showed an exponential increase with particle shape factor. Conclusions These findings provide a scientific basis for stability analysis and disaster prevention of tailings dams in permafrost regions.

Key words: tailings; freeze-thaw cycle; mechanical damage; microstructure