Minerals 2019, 9(1), 52; https://doi.org/10.3390/min9010052
In Situ X-Ray CT Investigations of Meso-Damage Evolution of Cemented Waste Rock-Tailings Backfill (CWRTB) during Triaxial Deformation
1
Beijing Key Laboratory of Urban Underground Space Engineering, Department of Civil Engineering, School of Civil & Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
2
Beijing General Research Institute of Mining and Metallurgy Technology Group, Beijing 102628, China
*
Author to whom correspondence should be addressed.
Received: 4 December 2018 / Revised: 3 January 2019 / Accepted: 6 January 2019 / Published: 16 January 2019
(This article belongs to the Special Issue Backfilling Materials for Underground Mining)
Abstract
This work presents an experimental study that focused on the meso-damage evolution of cemented waste rock-tailing backfill (CWRTB) under triaxial compression using the in situ X-ray computed tomography (CT) technique. Although numerous investigations have studied the magnitude of the strength of CWRTB material, the mesoscopic damage evolution mechanisms under triaxial deformation are still poorly understood. Artificial CWRTB samples with a waste rock proportion of 30% were prepared by mixing tailings, waste rock, cement, and water. A specific self-developed loading device was used to match the CT machine to real-time CT scanning for the CWRTB sample. A series of 2D CT images were obtained by performing CT imaging at five key points throughout the test and from three positions in the sample. The CT values, for the purpose of meso-damage evolution in CWRTB, were identified. The results showed that the axial stress–strain curve presented strain hardening characteristics. The CT data revealed the inhomogeneous damage field inside the CWRTB sample and the most severely damaged regions that were usually located at the waste block-tailings paste interfaces. The changes in CT values for the different regions of interest (ROI) revealed the complicated interactions between the waste blocks and the tailings paste matrix. The meso-structural changes, formation of the localized bands, and the associated stress dilatancy phenomenon were strongly influenced by the interactions between the waste blocks and tailing paste. View Full-TextKeywords:
cemented waste rock-tailings backfill (CWRTB); X-ray CT; triaxial test; meso-damage evolution
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Wang, Y.; Wang, H.; Zhou, X.; Yi, X.; Xiao, Y.; Wei, X. In Situ X-Ray CT Investigations of Meso-Damage Evolution of Cemented Waste Rock-Tailings Backfill (CWRTB) during Triaxial Deformation. Minerals 2019, 9, 52.
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