School of Energy Science and Engineering Collaborative Innovation Center of Coal Work Safety Henan Polytechnic University Jiaozuo 454003 China;
Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University) Ministry of Education Changsha 410083 China;
Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines Hunan Provincial Key Laboratory of Safe Mining Xiangtan 411201 China;
School of Civil Engineering Wuhan University Wuhan 430072 China;
High temperature; Coal; Microstructure; Mechanical behavior; Nuclear magnetic resonance;