1. Ph.D. Candidate, School of Resources and Geosciences, China Univ. of Mining and Technology, Xuzhou, CN, 221008, e-mail: gaoyue@cumt.edu.cn
2. Professor, School of Resources and Geosciences, China Univ. of Mining and Technology, Xuzhou, CN, 221008 (Corresponding author), e-mail: suiwanghua@cumt.edu.cn
3. Associate Professor, Dept. of Civil Engineering, Ryerson Univ., Toronto, CA, M5B 2K3, e-mail: jinyuan.liu@ryerson.ca