Optimization of Blasting‑Induced Roof Cutting Parameters in Key Stratum and Its Application in Gob‑Side Entry Retention Technology

In the field of mining, conventional methods that rely on protective coal pillars result in significant wastage of coal resources. To achieve the dual objectives of resource recovery and roadway stability control, this study utilizes theoretical analysis, numerical simulation, and field experiments to investigate the technology of gob‐side entry protection through blasting‐induced roof cutting for pressure relief under gently inclined coal seam conditions with hard roofs. The research demonstrates that implementing high‐level roof cutting can actively guide roof fracturing outside the coal pillar, thereby significantly reducing the peak lateral abutment pressure and shifting it deeper into the coal mass. A calculation formula for inter‐hole microsecond delay timing, based on the principle of vibration wave interference cancellation, and a method for determining the optimal spacing between blast holes and guide holes, grounded in stress wave superposition theory, were proposed, forming a precise blasting technique for controlled fracture formation. After field application, the deformation of the roadway surrounding rock was controlled within 35 mm, yielding favorable application results. The key stratum‐targeted roof cutting and refined blasting control technology proposed in this study hold theoretical significance and technical reference value for improving coal recovery rates and enhancing roadway stability control.