1. School of Resources & Civil Engineering, Northeastern University, 3-11 Wenhua Rd., Heping District, Shenyang 110819, P.R. China, http://orcid.org/0000-0001-8140-7723
2. State Key Laboratory for GeoMechanics and Deep Underground Engineering, Ding-11 College Rd., Haidian District, Beijing 100083, P.R. China
3. School of Resources & Civil Engineering, Northeastern University, 3-11 Wenhua Rd., Heping District, Shenyang 110819, P.R. China (Corresponding author), e-mail: nan_yangvip@126.com, http://orcid.org/0000-0002-8071-8164