Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements
The surrounding rocks of underground engineering are generally subjected to a biaxial compressive stress condition. The failure properties of rocks under such a stress condition are worthy of being studied to ensure the stability of surrounding rock. This study aims to investigate the mechanical cha...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2021-01-01
|
Series: | Applied Sciences |
Subjects: | |
Online Access: | https://www.mdpi.com/2076-3417/11/2/769 |
id |
doaj-58f25456cfd84aa3925ac09361c4711d |
---|---|
record_format |
Article |
spelling |
doaj-58f25456cfd84aa3925ac09361c4711d2021-01-15T00:06:13ZengMDPI AGApplied Sciences2076-34172021-01-011176976910.3390/app11020769Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial ConfinementsKun Du0Minghui Liu1Chengzhi Yang2Ming Tao3Fukang Feng4Shaofeng Wang5School of Resources and Safety Engineering, Central South University, Changsha 410083, Hunan, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, Hunan, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, Hunan, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, Hunan, ChinaChangchun Gold Research Institute Co. Ltd., Changchun 130012, Jilin, ChinaSchool of Resources and Safety Engineering, Central South University, Changsha 410083, Hunan, ChinaThe surrounding rocks of underground engineering are generally subjected to a biaxial compressive stress condition. The failure properties of rocks under such a stress condition are worthy of being studied to ensure the stability of surrounding rock. This study aims to investigate the mechanical characteristics and acoustic emission (AE) properties of granite, marble, and sandstone in biaxial compression tests. Under biaxial confinements, it is evident that the elastic moduli of the three types of rocks decrease, and the plasticity increases monotonously with the increase of the intermediate principal stress <i>σ</i><sub>2</sub>. As <i>σ</i><sub>2</sub> increases, the biaxial compressive strength <i>σ</i><sub>bcs</sub> of rock increases initially and subsequently decreases. The lateral strain ε<sub>2</sub> of rock under biaxial confinement is controlled by both <i>σ</i><sub>1</sub> and <i>σ</i><sub>2</sub>, and the restrain degree in the development of microcracks and the constrain extent in the expansion along the direction of σ<sub>2</sub> are both enhanced gradually with increase in <i>σ</i><sub>2</sub>. The sharp increase points of AE hit and AE count indicate that the failure will occur soon. The AF-RA distribution of AE signals shows that the increase of <i>σ</i><sub>2</sub> causes more tensile cracks in rock. According to the dip failure angle of macro-cracks in rock under biaxial confinement, the failure modes of granite and marble are slabbing, while failure mode of sandstone is shear. In addition, the <i>σ</i><sub>2</sub> has a positive effect on the mass ratio of large size fragments after rock failure. An exponent relationship between the <i>σ</i><sub>bcs</sub> and <i>σ</i><sub>2</sub> was found, and the inner apices–inscribed Drucker–Prager criterion can be used to predict the <i>σ</i><sub>bcs</sub> of rock.https://www.mdpi.com/2076-3417/11/2/769biaxial compression testbiaxial compressive strengthdeformationacoustic emissionintermediate principal stress |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kun Du Minghui Liu Chengzhi Yang Ming Tao Fukang Feng Shaofeng Wang |
spellingShingle |
Kun Du Minghui Liu Chengzhi Yang Ming Tao Fukang Feng Shaofeng Wang Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements Applied Sciences biaxial compression test biaxial compressive strength deformation acoustic emission intermediate principal stress |
author_facet |
Kun Du Minghui Liu Chengzhi Yang Ming Tao Fukang Feng Shaofeng Wang |
author_sort |
Kun Du |
title |
Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements |
title_short |
Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements |
title_full |
Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements |
title_fullStr |
Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements |
title_full_unstemmed |
Mechanical and Acoustic Emission (AE) Characteristics of Rocks under Biaxial Confinements |
title_sort |
mechanical and acoustic emission (ae) characteristics of rocks under biaxial confinements |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2021-01-01 |
description |
The surrounding rocks of underground engineering are generally subjected to a biaxial compressive stress condition. The failure properties of rocks under such a stress condition are worthy of being studied to ensure the stability of surrounding rock. This study aims to investigate the mechanical characteristics and acoustic emission (AE) properties of granite, marble, and sandstone in biaxial compression tests. Under biaxial confinements, it is evident that the elastic moduli of the three types of rocks decrease, and the plasticity increases monotonously with the increase of the intermediate principal stress <i>σ</i><sub>2</sub>. As <i>σ</i><sub>2</sub> increases, the biaxial compressive strength <i>σ</i><sub>bcs</sub> of rock increases initially and subsequently decreases. The lateral strain ε<sub>2</sub> of rock under biaxial confinement is controlled by both <i>σ</i><sub>1</sub> and <i>σ</i><sub>2</sub>, and the restrain degree in the development of microcracks and the constrain extent in the expansion along the direction of σ<sub>2</sub> are both enhanced gradually with increase in <i>σ</i><sub>2</sub>. The sharp increase points of AE hit and AE count indicate that the failure will occur soon. The AF-RA distribution of AE signals shows that the increase of <i>σ</i><sub>2</sub> causes more tensile cracks in rock. According to the dip failure angle of macro-cracks in rock under biaxial confinement, the failure modes of granite and marble are slabbing, while failure mode of sandstone is shear. In addition, the <i>σ</i><sub>2</sub> has a positive effect on the mass ratio of large size fragments after rock failure. An exponent relationship between the <i>σ</i><sub>bcs</sub> and <i>σ</i><sub>2</sub> was found, and the inner apices–inscribed Drucker–Prager criterion can be used to predict the <i>σ</i><sub>bcs</sub> of rock. |
topic |
biaxial compression test biaxial compressive strength deformation acoustic emission intermediate principal stress |
url |
https://www.mdpi.com/2076-3417/11/2/769 |
work_keys_str_mv |
AT kundu mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements AT minghuiliu mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements AT chengzhiyang mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements AT mingtao mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements AT fukangfeng mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements AT shaofengwang mechanicalandacousticemissionaecharacteristicsofrocksunderbiaxialconfinements |
_version_ |
1724337617296687104 |