doi:10.16186/j.cnki.1673-9787.2020050063

Received:2020/05/21

Revised:2020/07/25

Published:2022/03/15

Study on infrared radiation characteristics of layered gneiss

YAN Shunxi1,2; HUANGFU Run1,2; WANG Xiaolei1,2, JIANG Pengcheng1,2, ZHAN Sibo1,2

1.College of Mining Engineering, North China University of Science and Technology ,Tangshan  063210 ,Hebei, China;2.Hebei Province Key Laboratory of Mining Development and Safety Technique, Tangshan  063210 , Hebei, China

Abstract: In order to explore the rupture instability and infrared radiation temperature field evolution characteristics of different bedding dip gneisses,and to capture the precursor information of rock instability,uniaxial compression tests were carried out on five types of bedding dip gneiss.The results showed that,with the increase of bedding dip angle,the peak strength showed a trend of first decreasing and then increasing.The bedding structure effect of the peak strength of gneiss at 60° was the most obvious.Under the same inclination angles,the temperature field changed from uniform to concentrated distribution with the increase of stress.Under the same stress,the larger the inclination angle was,the sooner the concentrated distribution of high temperature bands could be observed.Fractal dimension,entropy and variance could effectively express the evolution processes of infrared radiation temperature field at the same inclination and different stress.The fractal dimension decreased as the energy released by the rock increases.The entropy decreased with the temperature field's larger fluctuation.The differentiation of temperature field was more significant with the larger variance.The variance was derived to obtain the temperature field differentiation rate.The differentiation rate exceeding the threshold was defined as an early warning signal.As the angle of sample was 30° or 90°,time warnings were earlier than the stress warning,and as the angle of sample was 0°,45° or 60°,stress warnings were slightly earlier than the time warning.

Key words:bedding effect;dip angle;gneiss;infrared radiation;early warning signature

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