Size effect analysis of remaining coal pillar on rock burst caused by fault

Mining activity near faults easily induces rock bursts, and reasonable reservation of coal pillars can effectively prevent this disaster. Therefore, this paper establishes an engineering-scale fast Lagrangian analysis of continua in 3 dimensions (FLAC3D) numerical model and rheological physical model of rock burst induction, studies the mining influence on the strata behaviors of fault band and elastic rock systems (abutment stress, fault plane stress, roof settlement, and fault slipping and its speed), and analyzes the effect of different remaining fault coal pillars on rock burst induction. The results show that in a large remaining coal pillar (LRFCP), mining activity has little influence on faults, while strata movement causes high-stress concentrations and a large accumulation of strain energy in the coal pillar, which easily induces a strain burst. Meanwhile, in a small remaining fault coal pillar (SRFCP), mining significantly affects the fault mechanical environment and its movement. The strata behaviors are coordinated variations of deformation and fault plane stress under the coupling of the mining effect and fault effect, which easily cause fault-slip bursts, and the fault effect is more prominent. Finally, the above results are verified by two cases regarding microseisms and shock bumps. The study results can provide theoretical significance and have guiding value for the face layout, fault coal pillar remainder, and evaluation and prevention of rock bursts.