1. School of Civil Engineering, Xuzhou University of Technology, Xuzhou, Jiangsu 221018, China
2. Institute of Mining Engineering, Shandong University of Science and Technology, Tai’an 271019, China
3. Shandong Energy Group, Jinan 250013, China
4. A Key Laboratory of Deep Coal Resource Mining, School of Mines, Ministry of Education of China, China University of Mining and Technology, Xuzhou 221116, China