1. Professor, School of Civil Engineering, State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing Univ., Chongqing 400044, China (corresponding author).
2. Ph.D. Candidate, School of Civil Engineering, State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing Univ., Chongqing 400044, China.
3. Professor, Dept. of Mechanical Engineering, Norwegian Univ. of Science and Technology, Trondheim 7491, Norway.