1. School of Civil Engineering, Xuzhou University of Technology, Xuzhou, China
2. State Key Laboratory for Geo-Mechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, China + School of Mathematics, China University of Mining and Technology, Xuzhou, Jiangsu, China
3. School of Mathematics, China University of Mining and Technology, Xuzhou, Jiangsu, China + College of Mining Engineering and Geology, Xinjiang Institute of Engineering, Urumqi, Xinjiang, China