Effects of thermal treatment on physical and mechanical characteristics of coal rock

• Published in: Journal of Central South University Vol. 23; no. 9; pp. 2336 - 2345
• Main Authors: Yin, Tu-bing, Wang, Pin, Li, Xi-bing, Shu, Rong-hua, Ye, Zhou-yuan
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.09.2016; Springer Nature B.V
• Subjects: Civil; Coal; Dynamic loads; Dynamic mechanical properties; Elastic deformation; Energy and Traffic Engineering; Engineering; Geological; Heat treatment; High temperature; Impact damage; Impact loads; Longitudinal waves; Mechanical properties; Metallic Materials; Modulus of elasticity; Physical properties; Split Hopkinson pressure bars; Stress-strain curves; Temperature effects; Wave velocity; rock mechanical property; dynamic mechanical property; split Hopkinson pressure bar (SHPB); high temperature; coal rock
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-016-3292-9

To study the physical and mechanical properties of coal rock after treatment at different temperatures under impact loading, dynamic compression experiments were conducted by using a split Hopkinson pressure bar (SHPB). The stress–strain curves of specimens under impact loading were obtained, and then four indexes affected by temperature were analyzed in the experiment: the longitudinal wave velocity, elastic modulus, peak stress and peak strain. Among these indexes, the elastic modulus was utilized to express the specimens’ damage characteristics. The results show that the stress–strain curves under impact loading lack the stage of micro-fissure closure and the slope of the elastic deformation stage is higher than that under static loading. Due to the dynamic loading effect, the peak stress increases while peak strain decreases. The dynamic mechanical properties of coal rock show obvious temperature effects. The longitudinal wave velocity, elastic modulus and peak stress all decrease to different extents with increasing temperature, while the peak strain increases continuously. During the whole heating process, the thermal damage value continues to increase linearly, which indicates that the internal structure of coal rock is gradually damaged by high temperature.