Numerical modelling of rockburst mechanism in a steeply dipping coal seam

Abstract

Rockbursts that occurred in steeply dipping coal seams (SDCSs) are frequent and hazardous, and the resultant damage characteristics are different from those in horizontal and slightly dipping coal seams. A rockburst case study is carried out in a representative SDCS to reveal the factors causing rockbursts in SDCSs with similar mining conditions. Parametric studies on rockburst triggering factors including mining depth, mechanical properties of backfill materials, lateral stress coefficient, and coal seam dip angle are conducted using numerical modelling techniques. The triggering factors are further validated through the analysis of the spatial distribution of microseismic events and rockburst sources, roadway damage characteristics, and surface fractures. The obtained results indicate the presence of an asymmetric stress field in the coal seams. The deformation of roof and rock pillar induced by caving mining exerts an obvious compressive and prying effect on the coal body. The study shows an inverse relationship between stress concentration and the backfill material stiffness, while the stress concentration and rockburst potential positively correlate with mining depth, lateral pressure coefficient, and coal seam dip angle. The stress concentration due to compressive and prying effect, combined with dynamic load generated by microseismic events, leads to the frequent rockburst hazards in SDCSs.