1. School of Mechanics & Civil Engineering, China Univ. of Mining & Technology, Xuzhou 221116, Jiangsu, CN
2. State Key Laboratory for Geomechanics & Deep Underground Engineering, China Univ. of Mining & Technology, Xuzhou 221116, Jiangsu, CN (Corresponding author), e-mail: kzhang@cumt.edu.cn
3. Deep Earth Energy Laboratory, Building 60, Monash Univ., VIC 3800, AU