NMR-based damage characterisation of backfill material in host rock under dynamic loading

International Journal of Mining Science and Technology

Guopeng Lin¹  Liuqing Hu²  Binglei Li²  Jiquan Lan²  Guangyao Si³ 

[1] Corresponding author.;College of Zijin Mining, Fuzhou University, Fuzhou 350108, China;School of Minerals and Energy Resources Engineering, University of New South Wales, Sydney 2205, Australia;

关键词: Dynamic loading;    Backfill-country rock system;    True triaxial test;    Coupled static and dynamic loads;    Nuclear magnetic resonance (NMR);    Damage evolution;   

DOI  :  

来源: DOAJ

【 摘 要 】

It is not uncommon that backfill material used in underground mining being exposed to repetitive dynamic stresses induced by blasting operations or rockburst events. Understanding the strength and fracture evolution of backfilled stopes is critical to maintain the long-term stope stability and ensure safe mining activities. This paper aims to study the damage evolution of the backfill material and its host rock behaviour under three-dimensional (3D) dynamic loading. Using a true-triaxial testing machine, multiple samples of backfill material enclosed by country rock were fabricated and tested under various dynamic loadings with different true-triaxial confining stress conditions. In addition, the nuclear magnetic resonance (NMR) measurement was conducted on the samples before and after exerting static and dynamic loading to obtain their porosity distribution changes. The experiment results suggested that with the increase of the dynamic loading, the porosity of the backfill sample goes through a two-stage process, which shows a slightly linear decrease and then followed by an exponential increase. The research findings can help understand the damage mechanism and fracture development of backfilled stopes and its host rock in deep underground mines, which are constantly subject to the combination of 3D static confining stress and dynamic loading.

【 授权许可】

Unknown