1. School of Resources and Civil Engineering, Suzhou University, Suzhou, Anhui 234000, China
2. National Engineering Research Center of Coal Mine Water Hazard Controlling, Anhui 234000, China
3. School of Mineral Resources and Geosciences, China University of Mining & Technology, Xuzhou, Jiangsu 221008, China
4. Key Laboratory of Coalbed Methane Resource and Reservoir Formation Process, Ministry of Education, Xuzhou, Jiangsu 221008, China