China Safety Science Journal ›› 2022, Vol. 32 ›› Issue (11): 65-73.doi: 10.16265/j.cnki.issn1003-3033.2022.11.2690

• Safety engineering technology • Previous Articles     Next Articles

Analysis of coal fracture evolution characteristics under different loading rates

XIAO Peng1,2(), GAO Zhen1,**(), SHUANG Haiqing1,2, WU Mingchuan1, CHENG Yueying1, GUO Chenhua1   

  1. 1 College of Safety Science and Engineering, Xi'an University of Science and Technology, Xi'an Shaanxi 710054, China
    2 Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education,Xi'an University of Science and Technology, Xi'an Shaanxi 710054, China
  • Received:2022-05-28 Revised:2022-09-11 Online:2022-11-28 Published:2023-05-28
  • Contact: GAO Zhen

Abstract:

In order to study the influence of loading rate on the evolution of coal fracture, uniaxial compression tests of coal under different loading rates were carried out. Taking raw coal samples as the research object, the relationship between coal mechanical parameters, deformation field evolution cloud map and acoustic emission signal parameters was analyzed by combining digital speckle technology and acoustic emission technology. The research shows that the compressive strength and elastic modulus of coal increase gradually with the increase of loading rate. The compressive strength increases by 25.49%, and the elastic modulus increases by 51.55%. The evolution nephogram of the coal deformation field and the spatial distribution of acoustic emission events can indicate the whole process of fracture development, expansion and fracture. With the increase of loading rate, the failure type of coal body changes from tensile failure to tensile shear composite failure. The relative displacement rate of the localization zone of the coal surface deformation field decreases gradually, and the peak count, peak energy and the number of acoustic emission events increase, while the cumulative count and cumulative energy decrease. The evolution nephogram of the deformation field and the spatial distribution of acoustic emission events can better reflect the evolution characteristics of fracture development, expansion and fracture during coal loading.

Key words: loading rate, coal, fracture evolution, evolution characteristics, uniaxial compression test, acoustic emission events