1. State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, No. 1 Daxue Rd., Xuzhou 221116, PR China (Corresponding author), e-mail: yangsqi@hotmail.com, https://orcid.org/0000-0003-1493-6136
2. State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, PR China