Study on Mechanical Failure and Energy Instability Mechanism of a Soft and Hard Composite Coal Seam in a Geological Anomaly Area

Coal and gas outbursts are increasingly frequent occurrences in coal mining production. Furthermore, geological anomaly areas are the primary sites of outburst incidents. This research proposed a coal seam model containing gas in geological anomaly area to better understand the impact of regional geological anomaly variables on the outburst. It was discovered that the excavation length had a larger effect on the plastic zone and energy instability than gas pressure and dip angle. Coal’s elastic energy was mostly impacted by excavation length, which subsequently had an impact on the chance of an outburst. Adsorbed gas’s expansion energy was mostly influenced by the original gas pressure, while both energies were impacted by the inclination angle. The outburst energy increased more under the influence of excavation spacing or gas pressure. When combined with the outburst case, it was discovered that the geological anomaly area raised the composite coal seam’s outburst probability. Additionally, when a geological anomaly area was present, the increase in gas pressure has a considerably larger effect on the energy than the excavation length. This paper’s research is of great significance for preventing mechanical failure of soft and hard composite coal seam (SHCC) in geological anomaly areas.