Mechanisms and Integrated Control of Mining-Induced Fracture Activation in Shallow Coal Seams in Response to Multi-Load Conditions

Understanding the mechanisms of fracture evolution in shallow coal seam mining is crucial for ensuring operational safety and environmental sustainability. This research integrates physical simulations and field measurements to investigate fracture dynamics in three strategically selected mining zones within the Shenfu Coalfield. These zones are characterized by coal seam thicknesses of 4–6 m, interlayer spacings of 20–40 m, and burial depths of 68–163 m. The study establishes a systematic classification of fractures based on direction and spatial characteristics. Directionally, fractures are categorized as upstream fractures that propagate upward from excavation zones and downstream fractures that extend toward the surface. Spatially, fractures include open-off cut fractures inclined at 60°–65°, dynamically periodic fractures that align with roof pressure cycles, and roadway-boundary fractures. Surface manifestations consist of permanent fissures exceeding 0.2 m in width, which require engineered control, as well as temporary fractures that demonstrate self-healing through strata recompaction. Key findings reveal a significant correlation between surface fracture spacing and periodic roof pressure intervals, with a correlation strength of R²=0.92 and statistical significance of p