Study on bump-prone property of coal under multi-stage confining pressure variable stress lower limit cyclic loading and unloading

• Published in: Mei kuang an quan Vol. 54; no. 10; pp. 107 - 116
• Main Authors: Chuanjiu ZHANG, Taotao DU, Jianhui REN, Xuanliang LI
• Format: Journal Article
• Language: Chinese
• Published: Editorial Office of Safety in Coal Mines 01.10.2023
• Subjects: bump-prone property; coal; confining pressure; cyclic loading and unloading; index of residual elastic energy
• ISSN: 1003-496X
• DOI: 10.13347/j.cnki.mkaq.2023.10.015

The study of coal bump-prone property under confining pressure plays a key role in exploring the formation mechanism of coal burst in deep underground mines. In order to explore the influence of different confining pressures on bump-prone property of coal, this paper carried out cyclic loading and unloading of coal with different stress lower limits under multistage confining pressures. The test results show that: under the confining pressure environment of 3 MPa, 6 MPa and 9 MPa, the compressive strength of coal specimens increased by 3.1%, 4.7% and 6.2% respectively after cyclic loading and unloading, and the axial strain increased by 0.61%, 0.42% and 0.28% respectively in the last stage of cyclic loading and unloading. The volumetric strain increases by 0.32%, 0.24% and 0.17%, respectively, indicating that the larger the confining pressure is, the stronger the deformation constraint is. With the increase of confining pressure, the cumulative number of AE events gradually decreases, the cumulative number of