Analysis of dynamic loading events and the risk of roadway rockburst

Abstract

Aim at the mechanism and risk assessment of rockburst of mine roadways, the energy release laws of roadway surrounding rock in different regional stress fields are analyzed. Combined with the impact of dynamic load events, the mechanical relationship between the initial stress field, the transient stress field generated by dynamic load events, and the failure of roadway surrounding rock is established. A calculation equation for the final boundary of the plastic zone of the roadway surrounding rock under the disturbance of dynamic load events is proposed, and the mechanism of rockburst induced by the joint action of dynamic load events and initial stress fields is explained. The risk of roadway rockburst under different factors is analyzed, and the risk intensity is divided into different locations where dynamic load events occurred based on the angle of occurrence of dynamic load events. The research results indicate that with the increasing differentiation of the regional stress field, the energy release of the roadway system after disturbance equilibrium will also increase, and the main area of the energy release is the direction of the maximum stress of the regional stress field. The roadway rockburst is the result of the joint action of the initial stress field and the transient stress field of the dynamic load event on the surrounding rock of the roadway. The impact of the dynamic load event will cause the final stress field of the roadway system to deflect, and the energy released by the coordination of the surrounding rock is the main cause of the rockburst. When the initial stress field is in the butterfly risk area, the risk of roadway rockburst is greater after being affected by dynamic load events, and the increase of the effective release energy of dynamic load events, the decrease of the event distance, and the increase of the proportion of shear wave energy will increase the risk of roadway rockburst. The angle of occurrence of dynamic load events affects the risk of roadway rock-burst. When dynamic load events occur in some strong risk areas and sub-strong risk areas, small dynamic load events are also highly possible to induce rockburst, and the risk of roadway rockburst is high. When dynamic load events occur in some weak risk areas, larger dynamic load events are also less likely to cause rockburst, and the risk of roadway rockburst is lower.

Keywords

• rockburst risk
• butterfly failure
• dynamic load events
• regional stress field