Energy Storage and Release of Class I and Class II Rocks

As underground excavations become deeper, violent rock failures associated with the sudden release of elastic energy become more prevalent, threatening the safety of workers and construction equipment. It is important to figure out the energy-related failure mechanisms of rocks. However, the energy...

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Main Authors: Yan Xing, Feng Gao, Zhizhen Zhang, Wenqi Zheng
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/16/14/5516
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author Yan Xing
Feng Gao
Zhizhen Zhang
Wenqi Zheng
author_facet Yan Xing
Feng Gao
Zhizhen Zhang
Wenqi Zheng
author_sort Yan Xing
collection DOAJ
description As underground excavations become deeper, violent rock failures associated with the sudden release of elastic energy become more prevalent, threatening the safety of workers and construction equipment. It is important to figure out the energy-related failure mechanisms of rocks. However, the energy evolution across the complete deformation of different types of rocks and the effect of high confinement on energy storage and release are not well understood in the literature. In this study, a series of cyclic triaxial compression tests were conducted for Class I and Class II rocks to investigate the confinement-dependent characteristics of energy evolution. The results showed that three types of energy evolution were identified as the rock behavior changed from brittle to ductile. The energy storage limit was linearly enhanced by confinement. The nonlinear increase in dissipated energy at peak stress with increasing confinement was suggested to indicate the start of the brittle–ductile transition. The post-peak fracturing process was characterized using the ratio of the local withdrawn elastic energy and fracture energy, and a novel energy-based index was proposed to quantify the failure intensity of the rock. This paper presents a complete investigation of the energy conversion characteristics of the rock, which may shed light on the failure mechanisms of violent rock failures in underground projects.
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spelling doaj.art-1e23088618ac41bc9a9c4b9d823a66032023-11-18T19:11:33ZengMDPI AGEnergies1996-10732023-07-011614551610.3390/en16145516Energy Storage and Release of Class I and Class II RocksYan Xing0Feng Gao1Zhizhen Zhang2Wenqi Zheng3State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaState Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, ChinaAs underground excavations become deeper, violent rock failures associated with the sudden release of elastic energy become more prevalent, threatening the safety of workers and construction equipment. It is important to figure out the energy-related failure mechanisms of rocks. However, the energy evolution across the complete deformation of different types of rocks and the effect of high confinement on energy storage and release are not well understood in the literature. In this study, a series of cyclic triaxial compression tests were conducted for Class I and Class II rocks to investigate the confinement-dependent characteristics of energy evolution. The results showed that three types of energy evolution were identified as the rock behavior changed from brittle to ductile. The energy storage limit was linearly enhanced by confinement. The nonlinear increase in dissipated energy at peak stress with increasing confinement was suggested to indicate the start of the brittle–ductile transition. The post-peak fracturing process was characterized using the ratio of the local withdrawn elastic energy and fracture energy, and a novel energy-based index was proposed to quantify the failure intensity of the rock. This paper presents a complete investigation of the energy conversion characteristics of the rock, which may shed light on the failure mechanisms of violent rock failures in underground projects.https://www.mdpi.com/1996-1073/16/14/5516brittle-ductile transitionclass II rockconfinementenergy evolutionfailure intensity
spellingShingle Yan Xing
Feng Gao
Zhizhen Zhang
Wenqi Zheng
Energy Storage and Release of Class I and Class II Rocks
Energies
brittle-ductile transition
class II rock
confinement
energy evolution
failure intensity
title Energy Storage and Release of Class I and Class II Rocks
title_full Energy Storage and Release of Class I and Class II Rocks
title_fullStr Energy Storage and Release of Class I and Class II Rocks
title_full_unstemmed Energy Storage and Release of Class I and Class II Rocks
title_short Energy Storage and Release of Class I and Class II Rocks
title_sort energy storage and release of class i and class ii rocks
topic brittle-ductile transition
class II rock
confinement
energy evolution
failure intensity
url https://www.mdpi.com/1996-1073/16/14/5516
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AT fenggao energystorageandreleaseofclassiandclassiirocks
AT zhizhenzhang energystorageandreleaseofclassiandclassiirocks
AT wenqizheng energystorageandreleaseofclassiandclassiirocks