Research on the Laws of Destructive Patterns and Control Measures of Overlying Rock in High‐Efficiency Large‐Scale Mining Faces

ABSTRACT With the continuous advancement of coal mining technology, the mining height and length of working faces in China have increased, and ultra‐long fully mechanized mining faces with large‐mining heights have become the prevailing layout trend in modern coal mines. As the working‐face dimensions increase, the range of overburden failure after coal seam extraction expands, resulting in an increased intensity of ground pressure manifestations. Consequently, the conventional method for determining the rated working resistance of hydraulic supports no longer applies. Therefore, investigating the overburden failure mechanism in ultra‐long fully mechanized mining faces with large‐mining heights is of great importance. Considering the 6306 working face of the Sihe Coal Mine as the research background, theoretical analysis, numerical simulation, and field measurements were employed to analyze the overburden failure range and structural characteristics under different face lengths. The results indicate that, during the mining process of the 6306 working face, the overburden is controlled by key strata and hard rock layers, forming a composite structure of “cantilever beam + voussoir beam.” On the basis of a stress‐transfer model of the composite structure, an analysis demonstrated that, when the working‐face length reached 320 m, the overburden failure range exerting a significant influence on hydraulic supports in the large‐mining‐height ultra‐long working face extended to 40.3 m, and the corresponding required working resistance of the hydraulic supports was calculated as 11,972 kN. Field ground pressure monitoring confirmed that hydraulic supports with a capacity of 12,000 kN could meet the roof control requirements, thus ensuring safe and efficient mining of the ultra‐long fully mechanized face with a large‐mining height.