Mechanism and experimental study of roof pre-splitting blasting for automated roadway formation without coal pillars

To investigate the influence mechanism of roof pre-splitting blasting on overlying strata movement in automated roadway formation without coal pillars, the mechanical response characteristics of the bearing structure of the overlying strata after pre-splitting blasting were analyzed. Comparative similar material simulation tests were conducted under two working conditions: with and without roof pre-splitting blasting. Combined with the proposed deformation analysis method based on settlement observation lines, key parameters of overlying strata movement under the two conditions were systematically compared. The results demonstrate that the influence of roof pre-splitting blasting on overlying strata movement is mainly reflected in three aspects: enhancing the caving and bulking effect of the overlying strata, weakening the fracturing and damage effect of the overlying strata, and reshaping the spatial effect of overlying strata fracturing. Based on in-situ borehole monitoring data obtained from the goaf surface, including flushing fluid loss, drilling speed, and core condition, the theoretical analysis and simulation test results were further validated. This study provides a scientific basis and theoretical support for precise control of strata movement, safe and efficient mining, and ecological environmental protection in mining areas under the condition of automated roadway formation without coal pillars.