1. State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology Xuzhou 221116 China
2. School of Mechanics and Civil Engineering China University of Mining and Technology Xuzhou 221116 China
3. College of Mathematics China University of Mining and Technology Xuzhou 221116 China
4. College of Mathematics and Systems Science Shandong University of Science and Technology Qingdao 266590 China
5. Institute of Engineering of Polytechnic of Porto Department of Electrical Engineering Porto Portugal