Abstract
In order to describe resistivity variation regularities during the process of damage evolution of loading coal mass more comprehensively and accurately, electrical resistivity and acoustic emission (AE) characteristics of coal mass were tested by 3532-50 LCR tester and AMSY-6 AE data acquisition system under the condition of multi-stage loading, and resistivity variation characteristics were analyzed with stress changing. The damage evolution process of coal mass was studied by the measurement of the AE parameters, and the resistivity curve was obtained in the damage conditions based on the relationship between the AE damage variable and the resistivity. The results show that resistivity and stress curves of coal mass have a good correspondence during the multi-stage loading, and the resistivity shows a trend of fluctuating downward with the increasing of stress. The resistivity increases sharply to the maximum value when the load increases to the ultimate compressive strength of specimens. AE information can reveal effectively damage evolution process of microcracks formation, expansion and fracture in coal mass under external force, and during multi-stage loading, the cumulative AE ringing counts curve of coal mass have three different types of growth trends: stable stage, sudden change stage, gradual increasing stage. Meanwhile, the relationship between resistivity and AE damage variable is established based on the formula of damage variable under uniaxial compression and combined with continuous damage mechanics, and its rationality is verified.
Highlights
The coal mass is affected by long-term geological processes, which is a complex mechanical medium
In the process of underground mining, the coal mass is affected by the interaction of original rock stress field and mining stress field, and the distribution state of primary cracks and mining cracks in coal mass will change with the stress state, resulting in internal damage and failure of coal mass [1,2]
The resistivity is an important parameter reflecting the change of microfractures in coal mass, and it will change abnormally in abnormal geological structure areas and stress concentration zones [3]
Summary
The coal mass is affected by long-term geological processes, which is a complex mechanical medium. The resistivity is an important parameter reflecting the change of microfractures in coal mass, and it will change abnormally in abnormal geological structure areas and stress concentration zones [3]. Studying the damage and failure characteristics under different loading stages and further revealing internal relation between resistivity and damage variable can be able to monitor the stability of surrounding rock and the occurrence of coal-rock dynamic disasters in practical engineering [4,5]. The loading deformation process of coal mass is accompanied by the phenomenon of internal microfractures in generating, expanding and fracturing and the evolution of AE energy, which can.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
