[1]Department of Resource and Civil Engineering, Shandong University of Science and Technology, Tai＇an 271000, China;
[2]Key Laboratory of Safety and High-efficiency Coal Mining, Ministry of Education, Anhui University of Science and Technology, Huainan 232001, China;
[1]Department of Resource and Civil Engineering, Shandong University of Science and Technology, Tai＇an 271000, China;
[3]Department of Building Engineering, Taishan Polytecnnic, Tai＇an 271019, China;
[4]State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Science, Wuhan 430071, China;
