Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests

As mining depth increases, the backfill mining method is more and more widely used in underground mines. The dynamic load generated by the blasting can affect the stability of the cemented tailings backfill (CTB). The CTB samples were prepared to conduct a test of the split Hopkinson pressure bar (S...

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Main Authors: Di Zheng, Weidong Song, Shuai Cao, Jiajian Li, Lijuan Sun
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Minerals
Subjects:
Online Access:https://www.mdpi.com/2075-163X/11/5/542
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spelling doaj-92476b24180e40df9bd1996ade5a303a2021-06-01T00:32:02ZengMDPI AGMinerals2075-163X2021-05-011154254210.3390/min11050542Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB TestsDi Zheng0Weidong Song1Shuai Cao2Jiajian Li3Lijuan Sun4School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaSchool of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaSchool of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaSchool of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaState Key Laboratory for Nonlinear Mechanics (LNM) Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, ChinaAs mining depth increases, the backfill mining method is more and more widely used in underground mines. The dynamic load generated by the blasting can affect the stability of the cemented tailings backfill (CTB). The CTB samples were prepared to conduct a test of the split Hopkinson pressure bar (SHPB) to investigate the dynamic disturbance of CTB. The present paper discusses dynamical mechanics, energy dissipation, and microstructure analysis of CTB. Micro-computer tomography (micro-CT) scanning of CTB samples after the SHPB test was performed to analyze the evolution of internal cracks. The experimental results showed that when the average strain rate (ASR) increased from 30 to 98 s<sup>−1</sup>, the dynamic uniaxial compression strength (DUCS) of the CTB showed a trend of first increasing and decreasing with the increase in ASR. The dynamic stress–strain pre-peak curve of CTB directly enters the linear elastic stage. As ASR increases, the absorbed energy of the CTB shows a trend of first increasing and then decreasing. Moreover, according to the micro-CT scanning results, the crack area of CTB accounts for about 16% of the sample near the incident bar and about 1% near the transmitted bar. The crack area ratio is exponentially related to the specimen height. These findings can provide reasonable dynamical CTB strength data selection for underground pillar mining.https://www.mdpi.com/2075-163X/11/5/542cemented tailings backfill (CTB)split Hopkinson pressure bar (SHPB)dynamical characteristicsenergy dissipationmicro-computer tomography
collection DOAJ
language English
format Article
sources DOAJ
author Di Zheng
Weidong Song
Shuai Cao
Jiajian Li
Lijuan Sun
spellingShingle Di Zheng
Weidong Song
Shuai Cao
Jiajian Li
Lijuan Sun
Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
Minerals
cemented tailings backfill (CTB)
split Hopkinson pressure bar (SHPB)
dynamical characteristics
energy dissipation
micro-computer tomography
author_facet Di Zheng
Weidong Song
Shuai Cao
Jiajian Li
Lijuan Sun
author_sort Di Zheng
title Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
title_short Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
title_full Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
title_fullStr Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
title_full_unstemmed Investigation on Dynamical Mechanics, Energy Dissipation, and Microstructural Characteristics of Cemented Tailings Backfill under SHPB Tests
title_sort investigation on dynamical mechanics, energy dissipation, and microstructural characteristics of cemented tailings backfill under shpb tests
publisher MDPI AG
series Minerals
issn 2075-163X
publishDate 2021-05-01
description As mining depth increases, the backfill mining method is more and more widely used in underground mines. The dynamic load generated by the blasting can affect the stability of the cemented tailings backfill (CTB). The CTB samples were prepared to conduct a test of the split Hopkinson pressure bar (SHPB) to investigate the dynamic disturbance of CTB. The present paper discusses dynamical mechanics, energy dissipation, and microstructure analysis of CTB. Micro-computer tomography (micro-CT) scanning of CTB samples after the SHPB test was performed to analyze the evolution of internal cracks. The experimental results showed that when the average strain rate (ASR) increased from 30 to 98 s<sup>−1</sup>, the dynamic uniaxial compression strength (DUCS) of the CTB showed a trend of first increasing and decreasing with the increase in ASR. The dynamic stress–strain pre-peak curve of CTB directly enters the linear elastic stage. As ASR increases, the absorbed energy of the CTB shows a trend of first increasing and then decreasing. Moreover, according to the micro-CT scanning results, the crack area of CTB accounts for about 16% of the sample near the incident bar and about 1% near the transmitted bar. The crack area ratio is exponentially related to the specimen height. These findings can provide reasonable dynamical CTB strength data selection for underground pillar mining.
topic cemented tailings backfill (CTB)
split Hopkinson pressure bar (SHPB)
dynamical characteristics
energy dissipation
micro-computer tomography
url https://www.mdpi.com/2075-163X/11/5/542
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