Mechanism of energy partition evolution of excavation roadway rockburst in coal seam under tectonic stress field

In the newly built deep mine,the rockburst in in-situ stress area gradually increases,and the site damage has regional and directional characteristics. In order to reveal this mechanism,a spatial partition evolution model of ex- cavation roadway surrounding rock under different heading speeds based on the numerical simulation under the condi- tion of deep tectonic stress field is established. The distribution boundary of energy unsteady release boundary is de- fined. Its distribution pattern and energy characteristics is analyzed. The conclusion is consistent with the situation on site. The results show that the surrounding rock of excavation roadway can be divided into six types of space according to the elasticity of the state and the characteristics of change. The energy accumulation area and the release area are both distributed in the roof and floor,but there is energy release area only in the roadway wall. When the heading speed increases,the direction of the elastic energy release area of the surrounding rock will expand to both ends at the same time,and the unsteady release boundary will be elongated along the way,and the range of rockburst risk will be expanded. In the tectonic stress field,the potential rockburst zone of the roadway is near the heading face,and the nec- essary conditions for its rockburst include the high in-situ stress and the rapid excavation. The potential burst start-up of roadway wall and face are located in shallow rock. The energy accumulation level of the roof and floor far away from the face is higher,and the roof and wall have bolt support,which lead to the rockburst damage strength of roof and floor far away from the face is greater than that close to the face. The conclusion is of significance for the study of the early warning and the method of detecting rockburst in the tectonic stress field.