State Key Laboratory of Coal Resources and Mining Safety China University of Mining and Technology Beijing 100083 China;
Institute of Rock Mechanics and Fractals China University of Mining and Technology Beijing 100083 China;
Institute of Rock Mechanics and Fractals China University of Mining and Technology Beijing 100083 China;
Sichuan University Chengdu 610065 China;
State Key Laboratory of Coal Resources and Mining Safety China University of Mining and Technology Beijing 100083 China;
Institute of Rock Mechanics and Fractals China University of Mining and Technology Beijing 100083 China;