Citation

Wang Y, Kong X, Shen W, li D, Liu C. China Saf. Sci. J. 2020; 30(9): 66-72.

Copyright

(Copyright © 2020, China Occupational Safety and Health Association, Publisher Gai Xue bao)

DOI

10.16265/j.cnki.issn.1003-3033.2020.09.010

PMID

unavailable

Abstract

In order to understand physical properties and structural characteristics of coal，ultrasonic propagation characteristics of coal samples at different height⁃to⁃diameter ratio were studied by adopting laboratory ultrasonic test technology and ultrasonic propagation theory. The results show that within a certain height⁃to⁃diameter ratio，velocity of ultrasonic waves shows a linear decreasing trend with high goodness of fit as the ratio increases，and P⁃wave velocity，1.6 times of S⁃wave velocity，is more sensitive for lithologic character. Moreover，theoretical and experimental results of mutually prove that Q value of ultrasonic quality factor also presents a linear decreasing trend with increase of the ratio. Based on analysis from three aspects of wave velocity，quality factor and dominant frequency respectively，it is determined that height⁃to ⁃diameter ratio of coal samples during test of their ultrasonic characteristics in laboratory is ≤2.0∶1. © 2020 China Safety Science Journal. All rights reserved.

Language: zh