Activation Mechanisms and Coupled Control of Mining-Induced Fractures in Shallow Coal Seams Under Multi-Load Conditions

Comprehending fracture evolution mechanisms in shallow coal seam mining is fundamental to ensuring operational safety and environmental sustainability. This research integrates physical simulations and field measurements to investigate fracture dynamics within Shenfu Coalfield's three strategically selected mining zones characterized by coal seam thicknesses of 4–6m, interlayer spacings of 20–40m, and burial depths of 68–163m. The study establishes a systematic fracture classification: directionally as upstream fractures propagating upward from excavation zones and downstream fractures extending surfaceward; spatially as open-off cut fractures at 60°–65° inclinations, dynamically periodic fractures synchronized with roof pressure cycles, and roadway-boundary fractures. Surface manifestations comprise permanent fissures exceeding 0.2m width requiring engineered control and temporary fractures demonstrating self-healing through strata recompaction. Key findings reveal a significant correlation between surface fracture spacing and periodic roof pressure intervals with correlation strength R²=0.92 and statistical significance p<0.01. Optimized 40–60m coal pillar spacing reduces boundary fracture propagation by 62% while confining differential surface settlement below 5%. Practical implementation of staggered pillar configurations achieves 78% fracture closure efficiency, permitting ecologically balanced mining with under 3% vegetation disturbance. These outcomes establish a validated predictive framework for overburden stability management while advancing sustainable extraction protocols through science-driven pillar engineering and fracture mitigation strategies.