ZHANG J, WEN G H, SUN Z B, et al.Experimental study on deformation and energy evolution characteristics of coal samples under high stress[J].Journal of Henan Polytechnic University(Natural Science) ,2022,41(6):1-7.

doi:10.16186/j.cnki.1673-9787.2021060015

Received:2021/06/07

Revised:2021/09/03

Published:2022/11/25

Experimental study on deformation and energy evolution characteristics of coal samples under high stress

ZHANG Jun1,2, WEN Guohui2, SUN Zhaobing2, ZHU Jianping2, DONG Runze2, LI Xiaohui2, SHI Zhen2, MENG Qingbin3, SUN Wen3, CHEN Yanlong3

1.School of Mines，China University of Mining and Technology，Xuzhou  221116，Jiangsu，China；2.Inner Mongolia Shuangxin Coal Mine Co.，Ltd.，Ordos  017000，Inner Mongolia，China；3.State Key Laboratory for Geomechanics and Deep Underground Engineering，China University of Mining and Technology，Xuzhou  221116，Jiangsu，China

Abstract:Physical and mechanical properties study of coal and rock has great significance for the safe mining in deep underground mines.The uniaxial and triaxial compression tests of deep coal samples were carried out using the MTS 815 rock mechanics test system，and the deformation，strength and energy evolution characteristics of the coal samples under high stress were analyzed.The results indicated that brittle failure occurs easily when the loaded coal got post-peak stage.Shear-tension combined failure occured under uniaxial and low confining pressure while shear failure occured under high confining pressure.The effect of confining pressure was obvious，and the peak stress and elastic modulus of coal samples increased with the elevation of confining pressure.Under low stress，the coal sample had an expansion before the peak.Under high stress，the coal sample continued to shrink in volume after yielding and expansion occured when it penetrated the fracture surface.The coal sample absorbed part of the work done by the testing machine and stored it in the form of elastic deformation energy.When the internal structure and stress state of coal sample were changed，energy was dissipated in the form of damage energy and plastic energy.The high confining pressure improved the energy absorption capacity of the coal sample，and the elastic deformation energy was dominant in the pre-peak stage，while the dissipative deformation energy was dominant in the post-peak stage.

Key words:high stress;triaxial compression;deformation characteristic;strength characteristic;energy evolution

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