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Geomechanics and Engineering
  Volume 15, Number 4, July20 2018, pages 1017-1027
DOI: http://dx.doi.org/10.12989/gae.2018.15.4.1017
 


Mechanical behavior of rock-coal-rock specimens with different coal thicknesses
Wei-Yao Guo, Yun-Liang Tan, Feng-Hai Yu, Tong-Bin Zhao, Shan-Chao Hu, Dong-Mei Huang and Zhe Qin

 
Abstract
    To explore the influence of coal thickness on the mechanical behavior and the failure characteristics of rock-coal-rock (RCR) mass, the experimental investigation of uniaxial compressive tests was conducted first and then a systematic numerical simulation by particle flow code (PFC2D) was performed to deeply analyze the failure mechanical behavior of RCR specimens with different coal thicknesses in conventional compression tests. The overall elastic modulus and peak stress of RCR specimens lie between the rock and the coal. Inter-particle properties were calibrated to match the physical sample strength and the stiffness response. Numerical simulation results show that the deformation and strength behaviors of RCR specimens depend not only on the coal thickness, but also on the confining pressure. Under low confining pressures, the overall failure mechanism of RCR specimen is the serious damage of coal section when the coal thickness is smaller than 30 mm, but it is shear failure of coal section when the coal thickness is larger than 30 mm. Whereas under high confining pressures, obvious shear bands exist in both the coal section and the rock section when the coal thickness is larger than 30 mm, but when the coal thickness is smaller than 30mm, the failure mechanism is serious damage of coal section and shear failure of rock section.
 
Key Words
    rock mechanics; RCR combined body; particle flow; confining pressure; failure; mechanical behavior
 
Address
Wei-Yao Guo, Yun-Liang Tan, Feng-Hai Yu, Tong-Bin Zhao, Shan-Chao Hu, Dong-Mei Huang: 1.) State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China
2.) National Demonstration Center for Experimental Mining Engineering Education, Shandong University of Science and Technology,Qingdao 266590, China

Zhe Qin: National Demonstration Center for Experimental Mining Engineering Education, Shandong University of Science and Technology,Qingdao 266590, China
 

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