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Geomechanics and Engineering
  Volume 11, Number 3, September 2016, pages 345-359
DOI: http://dx.doi.org/10.12989/gae.2016.11.3.345
 


Failure characteristics of combined coal-rock with different interfacial angles
Tong-Bin Zhao, Wei-Yao Guo, Cai-Ping Lu and Guang-Ming Zhao

 
Abstract
    In order to investigate the influence of the interfacial angel on failure characteristics and mechanism of combined coal-rock mass, 35 uniaxial/biaxial compressive simulation tests with 5 different interfacial angels of combined coal-rock samples were conducted by PFC2D software. The following conclusions are drawn: (1) The compressive strength and cohesion decrease with the increase of interfacial angle, which is defined as the angle between structure plane and the exterior normal of maximum principal plane, while the changes of elastic modulus and internal friction angle are not obvious; (2) The impact energy index KE decreases with the increase of interfacial angle, and the slip failure of the interface can be predicted based on whether the number of acoustic emission (AE) hits has multiple peaks or not; (3) There are four typical failure patterns for combined coal-rock samples including I (V-shaped shear failure of coal), II (single-fracture shear failure of coal), III (shear failure of rock and coal), and IV (slip rupture of interface); and (4) A positive correlation between interfacial angle and interface effect is shown obviously, and the interfacial angle can be divided into weak-influencing scope (0-15°), moderate-influencing scope (15-45°), and strong-influencing scope (> 45°), respectively. However, the confining pressure has a certain constraint effect on the interface effect.
 
Key Words
    particle flow; combined coal-rock; interfacial angle; failure pattern; mechanical properties
 
Address
(1) Tong-Bin Zhao, Guang-Ming Zhao:
Key Laboratory of Safety and High-efficiency Coal Mining, Ministry of Education (Anhui University of Science and Technology), Huainan, Anhui, 232001, P.R. China;
(2) Tong-Bin Zhao, Wei-Yao Guo:
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, Shandong 266590, P.R. China;
(3) Cai-Ping Lu:
School of Mining Engineering, Key Laboratory of Deep Coal Resource Mining (Ministry of Education), China University of Mining and Technology, Xuzhou, Jiangsu 221116, P.R. China.
 

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