Numerical Study on Coal Burst Proneness Characteristics of Fissured Coal Mass

Coal burst proneness of coal mass is a leading factor of coal burst which is influenced by fissures. In this paper, the elastic strain energy (ESE) and residual energy index (REI) were used as coal burst proneness indicators. The calibrated PFC2D models of coal specimens with various fissure configurations were established, and uniaxial compression tests were conducted. It was found that the uniaxial compressive strength (UCS), ESE, and REI for three types of fissured coal specimen were similar. The aforementioned three parameters decrease as the inclination angle increases from 0° to 30°. On the other hand, these parameters increase as the inclination angle increases from 30° to 90°. Through the coal burst proneness comparison of various fissure configurations, it was found that the coal burst proneness in the condition of two coplanar-parallel fissures was greater than that in the condition of a single fissure, whereas the coal burst proneness in the condition of two non-coplanar-parallel fissures was the lowest. The crack initiation stress, crack initiation stress level, and elastic strain energy distribution could explain the influence mechanism of fissures on the coal burst proneness. These results can be used as a guideline for forecasting and preventing coal burs