Impacts of thermal shocks on meso-damage and mechanical properties of coal

doi:10.16265/j.cnki.issn 1003-3033.2020.12.012

Abstract

Abstract: In order to study correlation between thermal damage and mechanical performance of coal after thermal shocks at different temperature, with deep coal of Pingmei No. 10 Mine as a research object, experiment was conducted by using universal testing machine, constant temperature box, ultrasonic detector and 4 K measuring camera. Meso-damage evolution and mechanical characteristics of coal after thermal shock were studied. The results show that as temperature rises, coal body produces a lot of meso-visible damage, and coal strength weakens. Box dimension D_B of fracture network can be used as an index to quantitatively characterize degree of coal damage. When thermal shock temperature exceeds 200 ℃, destruction of coal samples changes from elastic brittleness to ductile-plastic state, and such destruction after thermal shock cooling is irrecoverable. Therefore, attention still needs to be paid to changes in mechanical properties caused by thermal damage after coal seam spontaneously extinguishes in engineering practice.

Key words: thermal shocks, deep coal, meso-damage, mechanical characteristics, box dimension, ultrasonic

CLC Number:

X936

QI Xiaohan, MA Heng, WANG Xiaoqi, ZHANG Zunguo, LYU Youchang. Impacts of thermal shocks on meso-damage and mechanical properties of coal[J]. China Safety Science Journal, 2020, 30(12): 85-92.

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