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Experimental Study on the Mechanical Behavior and Failure Characteristics of Layered Coal at Medium Strain Rates
- Source :
- Energies; Volume 14; Issue 20; Pages: 6616, Energies, Vol 14, Iss 6616, p 6616 (2021)
- Publication Year :
- 2021
- Publisher :
- MDPI AG, 2021.
-
Abstract
- The study of the mechanical properties and failure behaviors for coal with different bedding structures at various medium strain rates is of great importance for revealing the mechanism of rock burst. In our study, we systematically analyze the uniaxial compressive strength (UCS), acoustic emission (AE) characteristics, failure pattern, and risk of rock burst on coal specimens with two bedding orientations under ranged in strain rates from 10ā4 sā1 to 10ā2 sā1. The results reflect that and the bedding direction and the strain rates significantly affect the UCS and failure modes of coal specimens. The UCS of coal specimens with loading directions perpendicular to bedding planes (horizontal bedding) increases logarithmically with increasing strain rate while the UCS increases first and then decreases of coal specimens with loading directions parallel to bedding planes (vertical bedding). The AE cumulative energy of the specimens with horizontal bedding is an order of magnitude higher than that of specimens with vertical bedding. However, it is independent of the strain rates. The energy release rates of these two types of bedded coal specimens increase in a power function as the strain rate increases. The coal specimens with horizontal bedding show violent failure followed by the ejection of fragments, indicating a high risk of rock burst. On the other hand, the coal specimens with vertical bedding exhibit a tensile splitting failure with a low risk of rock burst. Strain localization is a precursor of coal failure, and the concentration area of local principal strain is highly consistent with the initial damage area, and the area where the principal strain gradient is significantly increased corresponds to the fracture initiation area.
- Subjects :
- Technology
strain rates
bedding planes
energy density
failure
deformation field
rock burst
Control and Optimization
Materials science
Bedding
Energy Engineering and Power Technology
Rock burst
Ultimate tensile strength
Coal
Electrical and Electronic Engineering
Composite material
Engineering (miscellaneous)
Strain (chemistry)
Renewable Energy, Sustainability and the Environment
business.industry
Strain rate
Acoustic emission
Fracture (geology)
business
Energy (miscellaneous)
Subjects
Details
- ISSN :
- 19961073
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Energies
- Accession number :
- edsair.doi.dedup.....145f5d00276ec2785eedcc3399cf633f