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Geomechanics and Engineering
  Volume 20, Number 1, January10 2020 , pages 055-66

Energy evolution characteristics of coal specimens with preformed holes under uniaxial compression
Na Wu, Zhengzhao Liang, Jingren Zhou and Lizhou Zhang

    The damage or failure of coal rock is accompanied by energy accumulation, dissipation and release. It is crucial to study the energy evolution characteristics of coal rock for rock mechanics and mining engineering applications. In this paper, coal specimens sourced from the Xinhe mine located in the Jining mining area of China were initially subjected to uniaxial compression, and the micro-parameters of the two-dimensional particle flow code (PFC2D) model were calibrated according to the experimental test results. Then, the PFC2D model was used to subject the specimens to substantial uniaxial compression, and the energy evolution laws of coal specimens with various schemes were presented. Finally, the elastic energy storage ratio m was investigated for coal rock, which described the energy conversion in coal specimens with various arrangements of preformed holes. The arrangement of the preformed holes significantly influenced the characteristics of the crack initiation stress and energy in the prepeak stage, whereas the characteristics of the cumulative crack number, failure pattern and elastic strain energy during the loading process were similar. Additionally, the arrangement of the preformed holes altered the proportion of elastic strain energy U_e in the total energy in the prepeak stage, and the probability of rock bursts can be qualitatively predicted.
Key Words
    coal specimen; preformed hole; particle flow code (PFC); energy accumulation; energy dissipation; eastic energy storage ratio
Na Wu and Zhengzhao Liang:State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, China

Jingren Zhou: State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu 610065, China

Lizhou Zhang: Chongqing Survey Institute, Chongqing, 401121, China

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